|
||
ARTICLE |
CORRESPONDENCE Peter Parham: peropa{at}stanford.edu OR Makoto Yawata: myawata{at}stanford.edu
|
|
|---|
M. Yawata and N. Yawata contributed equally to this work.
Human killer cell immunoglobulin-like receptors (KIRs) and murine lectin-like Ly49 receptors perform orthologous functions despite their striking difference in protein structure and evolutionary origin (1, 2). As receptors for polymorphic MHC class I, KIR and Ly49 regulate NK cell tolerance and response (3). Independently, the human KIR and murine Ly49 gene families acquired some remarkably similar features, including variegated expression (46), signaling pathways (7), and haplotypes varying in gene content, allelic polymorphism, and signaling potential (8). Two groups of human KIR haplotypes are defined (9, 10). Group A haplotypes have a fixed organization of seven genes, most with inhibitory potential; the group B haplotypes have a variable number of KIR genes, many with activating function. Clinical studies have correlated KIR gene content with infection, cancer, autoimmunity, pregnancy syndromes, and transplant outcome (1116). Most of these associations are with activating KIR genes and group B haplotypes and favor success in reproduction and fighting infection, but also in increased autoimmunity (3).
Although the inhibitory receptors for HLA-A (KIR3DL2), -B (3DL1), -C (2DL1, 2 and 3), and the activating receptor for HLA-G (2DL4) are well studied (1720), the functional effects of their polymorphism remain largely unexplored. Ligands for the inhibitory 2DL5 and the activating 2DS1, 2, 3, 4, 5, and 3DS1 are unknown or uncertain. The NK cell repertoire depends on both KIR and HLA polymorphisms. Thus, KIR and HLA identical siblings have similar NK cell repertoires, whereas siblings differing at KIR or HLA exhibit a range of phenotype difference (21). Uncertain from that analysis was whether HLA serves to make positive or negative selection. Complicating further investigation of KIRHLA interactions has been the extent of their diversity. Population comparisons revealed ethnic differences in the ratio of group A and B KIR haplotypes. In East Asian populations, the simpler group A haplotypes dominate, suggesting their KIR diversity might be more simple and experimentally more tractable than for Caucasians (2224). Here, in-depth analysis of KIR genotype, phenotype, and function in the Japanese shows this hypothesis to be true.
![]()
RESULTS
Top
Abstract
RESULTS
DISCUSSION
MATERIALS AND METHODS
References
KIR gene content was determined for 132 unrelated Japanese donors. 11 KIR genotypes were distinguished (Fig. 1). With a frequency of 80%, the group A haplotypes dominated. These results extend the preliminary study of 41 donors (22), giving confidence that the results obtained here well represent the KIR system of the Japanese population. Full-length cDNA from KIR expressed in peripheral blood was cloned and sequenced from 53 panel members. In selecting donors and the KIR to be sequenced from each donor, we sampled the full range of the panel's genotypes (Fig. 1) and phenotypes (Fig. 2); 1825% of donors positive for each KIR were analyzed by cDNA cloning and sequencing, predicting detection of all alleles with >6% frequency.
|
|
Polymorphism modulates the level and frequency of KIR3D expression
The variation in KIR phenotype of NK cells from 104 donors was assessed by flow cytometry using four anti-KIR antibodies and correlated with genotype (Fig. 2). The five KIR3DL1 allotypes had different levels of DX9 binding. The levels ranged over an order of magnitude, with the hierarchy 3DL1*005<*007<*001<*020<*01502 (Fig. 3 A, left). Comparison of different anti-KIR3DL1 antibodies and of DX9 binding kinetics showed the allotypic differences are the result of the abundance of cell surface 3DL1, not variable affinity for DX9 (Fig. S2, available at http://www.jem.org/cgi/content/full/jem.20051884/DC1, and references 2527). Also correlating with binding level was the frequency of cellular expression so that high-binding allotypes (*001, *020, and *01502) were expressed by a larger proportion of NK cells than low-binding allotypes (*005 and *007) (Fig. 3 A, right). The frequency of NK cell expression also increased with gene dose: individuals having two low or high expressing 3DL1 allotypes had mean frequencies of expression that were 1.7- and 1.9-fold greater, respectively, than individuals having one.
|
For 2DL1/S1, the frequency of NK cells binding EB6 and their binding level both increased with the number of genes encoding KIR that bind the antibody (Fig. 3 C). Although no effects correlating with 2DL1 polymorphism were observed, the panel's high 2DL1*00302 frequency suggests that its high binding could have obscured the effects of low-binding allotypes in heterozygotes. Regarding the anti-2DL2/3+2DS2 antibody (DX27), panel members were either homozygous for 2DL3 or had one copy each of 2DL2, 2DL3, and 2DS2. Donors with the latter genotype had a similar frequency of antibody-binding NK cells, but a substantially increased level of binding (Fig. 3 C).
Cognate HLA class I increases the frequency of NK cells expressing inhibitory KIR
HLA-A, -B, -C types for the panel were determined at high resolution (Fig. S3 A, available at http://www.jem.org/cgi/content/full/jem.20051884/DC1). Both the alleles and their frequencies were consistent with previous studies (28, 29). Hardy-Weinberg equilibrium was observed for KIR and HLA (Fig. S3 B). Distinguishing Japanese from Caucasians are the frequencies of HLA-C ligands for KIR2DL. In Caucasians, 66% of HLA-C allotypes have C1 (the 2DL2/3 ligand) and 34% have C2 (the KIR2DL1 ligand); whereas in Japanese, 92% have C1 and 8% have C2. Thus, almost all Japanese use C1 as a self-ligand for inhibitory KIR, whereas a small minority use C2. The frequency of HLA-A3/11 ligands for 3DL2 is also lower in Japanese (8%) than in Caucasians (22%), whereas they have identical frequency for HLA-Bw4, the 3DL1 ligand (36%).
KIR phenotypes were compared for donors who have or lack a cognate HLA class I ligand for particular KIR. In several combinations, presence of cognate ligand increased the frequency of NK cells expressing the KIR (Fig. 4 A), while decreasing the amount of KIR-specific antibody that is bound (Fig. 4 B). In 2DL1 homozygotes, the presence of cognate C2 almost doubled the frequency of 2DL1+ NK cells while reducing the level of anti-2DL1 binding by 26%. Although the panel's high C1 frequency precluded comparable analysis of 2DL2/3, the two donors who lacked C1 showed decreased frequency of 2DL2/3-expressing cells and reduced levels of antibody binding (Fig. S4, available at http://www.jem.org/cgi/content/full/jem.20051884/DC1). C1 homozygotes had decreased binding of anti-2DL2/3 to NK cells compared with C1/C2 heterozygotes. Presence of Bw4 significantly increased the frequency of cells expressing 3DL1 for donors having two high-binding 3DL1 allotypes and decreased the level of anti-KIR3DL1 bound for donors having one high-binding 3DL1 allotype (Fig. 4, A and B). For donors having one high-binding 3DL1 allotype, paired with a low binding allotype or 3DS1, there was little effect on expression frequency, as also seen for donors having two low-binding allotypes (Fig. 4 C, top).
|
Allelic polymorphism modulates the inhibitory function of KIR3DL1
Approximately one third of the Japanese population has C1-2DL3 as the only functional inhibitory KIRHLA class I interaction, while one half of the population can also use the Bw43DL1 interaction. Although 2DL3 has little polymorphism in the Japanese, 3DL1 variation is substantial (Fig. 1). Consequently, the Bw43DL1 interaction is a potentially important source of functional NK cell diversification in the Japanese population. To address this question, the functions of the five 3DL1 allotypes present in the Japanese panel were compared.
PBMCs from 13 donors, each having a high- and low-binding 3DL1 allotype, were challenged with class Ideficient 721.221 cells and with 221 cells transfected with HLA-B*5801, a 3DL1 ligand. In response to 221 cells, 3DL1+ NK cells produced IFN-
as detected by intracellular staining. A diminished response was made to 221- B*5801, the inhibition varying 4090% between the five 3DL1 allotypes (Fig. 5, top). The hierarchy for increasing inhibition was 3DL1*007<*020<*01502<*005<*001. That 3DL1 polymorphism modulates a major NK cell effector function demonstrates its functional importance. Of note, the two allotypes giving strongest inhibition are those expressed at intermediate (3DL1*001) and lowest levels (3DL1*005).
|
Positive and balancing selection of KIR
70 allele-level KIR genotypes were distinguished in the panel. From these genotypes and the sequences of prototypical group A (GenBank accession no. AC011501) and group B (GenBank accession no. AY320039) haplotypes, the structures of Japanese KIR haplotypes were inferred by two independent methods. The 20 most frequent haplotypes were identically ranked (Fig. 6 A). Each was identified in two or more donors and, collectively, they account for 83.4% of the panel's haplotypes. In both gene content and allelic polymorphism, the telomeric part of Japanese KIR haplotypes is more variable than the centromeric part. Together, the 12 deduced A haplotypes comprise 67.7% of total haplotypes compared with 15.7% for the 8 deduced B haplotypes. One A haplotype is markedly more common (35.7%) than any other haplotype (<9%) and, for each of its component KIR genes, this haplotype has the dominant allele.
|
Linkage disequilibrium (LD) can indicate positive selection (33). Haplotype homozygosity revealed relatively high LD throughout the Japanese group A haplotypes; in particular, from 2DL4 through 3DL1 to 2DS4 (Fig. S5, available at http://www.jem.org/cgi/content/full/jem.20051884/DC1). Within this core region, the five 3DL1 alleles are linked with different combinations of alleles for the other two genes. These various cores are further diversified by combination with different 3DL2 alleles, the number depending on the core (Fig. 6 D). For example, 3DL1*005 pairs with four 3DL2 alleles, whereas the haplotype containing the dominant 3DL1*01502 allele is almost homogeneous, which is strong evidence for its positive selection, a selective sweep. As an independent assessment, the Ewens-Watterson homozygosity statistic was calculated for the centromeric and telomeric parts of the group A haplotypes and tested for departure from neutrality. In both parts of the KIR locus, signatures of positive selection were detected (Fig. 6 C, below the panel).
These analyses show that positive selection drove one group A haplotype to high frequency, such that its component alleles are now the dominant alleles of the polymorphic KIR genes. Positive selection also homogenized the centromeric part of the KIR locus. In contrast, balancing selection on telomeric KIR has maintained a variety of other haplotypes and their component alleles at intermediate frequencies. Because of these contrasting selections, a majority of Japanese (
75%) have the same centromeric KIR genes, including the HLA-Cspecific KIR2DL, but differ in the telomeric genes, including the HLA-A and -Bspecific KIR3D.
In addition to the 20 haplotypes shown in Fig. 6 A, 24 rarer haplotypes were deduced by assuming patterns of LD defined previously in other populations (34). Of the 44 haplotypes, 24 were group A and 20 group B. 30 of the 44 haplotypes share some alleles with the most common haplotype (no. 1) (Fig. S6, available at http://www.jem.org/cgi/content/full/jem.20051884/DC1). As well as a high frequency group A haplotype, the Japanese population has an abundance of low frequency A and B haplotypes with centromeric and telomeric motifs distinct from those present in the common haplotypes. These provide a pool of diverse functional potential for natural selection to operate on in the future.
Non-random associations of KIRHLA in females
Systematic analysis revealed combinations of KIR and HLA genes in the donor panel at non-random frequencies. Stratification by sex showed that the effect was confined to females (Fig. 7). Deleted, nonfunctional forms of 2DL4 (35) preferentially associated with C2, whereas homozygosity for functional, full-length 2DL4 correlated negatively with C2. 3DL1*005 preferentially associated with Bw4, a combination also favoring inhibitory interaction. Although C2 and Bw4 are in strong LD in Caucasians, that is not so for Japanese, for whom only 40% of C2-carrying haplotypes also have HLA-Bw4 (36). Also, only 50% of donors carrying C2 have Bw4 (8 out of 16), a neutral distribution confirming the independence of C2 and Bw4 in the panel. Association with Bw4 is thus an independently associated factor and not a consequence of LD with C2. Weaker trends were HLA-C2 with 3DL1*005 or *001, the most potent inhibitors (Fig. 5), whereas 3DL1*01502, the dominant allotype and less potent inhibitor, correlated negatively with C2.
|
|
| DISCUSSION |
|---|
|
|
|---|
For mice, it has been proposed that sequential or stochastic expression of inhibitory self-reactive receptors occurs until cumulative inhibition reaches some threshold, whereupon further receptor acquisition stops (3840). Our results fit with this type of model. That the cognate ligand has not been observed to elevate receptor expression frequency in mice could reflect a difference in the mechanism between the two species or in the mode of analysis. For example, the presence in mice of multiple Ly49 products with overlapping ligand specificity could have obscured the positive effect, as we observed for humans with multiple KIRHLA pairs.
KIR polymorphism modulates NK cell effector function
For
33% of the Japanese population, C1 is the only self-ligand for inhibitory KIR. Because the Japanese are practically monomorphic for KIR2D and polymorphic for KIR3DL1, they provided a good context in which to investigate the function of 3DL1 polymorphism. The five 3DL1 allotypes present in the Japanese differ in their capacity to inhibit NK cell function; they also differ in repertoire, which is the frequency and level of cell surface expression. Much evidence shows that DX9 binding measures the amount of cell surface KIR3DL1 (Fig. S10 and references 2527), so the allotypic differences observed are not the result of varying affinity for DX9.
The allotypic differences in the frequency and level of KIR3DL1 expression are distinguished from those caused by cognate ligand and represent a ligand-independent influence of 3DL1 polymorphism on the primary NK cell repertoire. The effects of cognate 3DL1Bw4 interactions are also modulated by KIR3DL1 polymorphism. Notably, the increase in frequency induced by the cognate ligand is greater for high than for low-expressing KIR3DL1 allotypes. The overall trend is for inhibitory capacity to increase with the level and frequency of 3DL1 expression, an exception being 3DL1*005, which combines low frequency and level of expression with strong inhibitory function.
KIR diversity is subject to positive and balancing selection
An outstanding question is whether the haplotypic diversity and allelic polymorphism of KIR genes arose from functional selection or neutral change. From functional assay and statistical analysis, we provide evidence that balancing selection maintains a pool of alleles and haplotypes with distinguishable functions upon which positive selection can act. In the Japanese, one group A KIR haplotype has risen to unusually high frequency, a selection that may have been targeted to the centromeric KIR genes, because the 2DL1*00302 and 2DL3*001 alleles of the selected haplotype are at frequencies approaching 90%. In contrast, in the telomeric parts of the locus, the balancing selection retained diversity as exemplified by the even frequency of other group A and group B haplotype motifs and the distribution of the six core group A haplotype structures (Fig. 8). In these regions, the selected haplotype encodes functional KIR2DL4 and KIR2DS4 forms and a KIR3DL1 allotype giving moderate inhibition. Within the set of Japanese A haplotypes, it is one that combines a full set of functional genes and good potential for both inhibition and activation. Because of this haplotype, the frequency of functional 2DL4 and 2DS4 alleles in the Japanese is much higher than in Caucasians (35, 41). One possible cause of the selective sweep is an epidemic of infectious disease where the selected haplotype enhanced the chance of surviving infection. Alternatively, women carrying this less inhibitory, more activating form of A haplotype could have above average reproductive success, as might be suggested from the results of Hiby et al. (15).
Evidence for selection of KIRHLA combinations in female genotypes
An unexpected and thought-provoking discovery is the over- and underrepresentation of certain KIRHLA class I combinations in Japanese females. Because KIR and HLA are on different chromosomes, the overrepresented combinations must confer some selective advantage, whereas the underrepresented combinations are disadvantageous. As only NK cells and T cells express KIR, the selective mechanism likely involves one or both of these cell types. Candidate mechanisms can be distinguished according to when they might act: before conception, during fetal life, or after birth.
Acting before conception and biasing progeny genotype is mate choice. Extensive literature points to MHC polymorphism influencing the choice of sexual partners (4244), and it is plausible that this biology could extend to combinations of KIR and HLA polymorphisms. For example, preferential choice of Bw4+ partners by Bw4+, 3DL1*005+ individuals would lead to enrichment in the next generations of genotypes combining Bw4 homozygosity with 3DL1*005. For mate choice, a cause for the female bias is hard to envisage.
As only a fraction of human embryos survive implantation and fetal life (45), there is potential for improving survival. There are also sex differences in the mechanisms by which embryos fail to survive and the timing of these events (46). For example, for embryos with normal karyotype, the rate of spontaneous abortion during early pregnancy is greater for females than males, so any combination of genetic factors that reduced the effect would be specifically overrepresented in the female population (46). Candidate mechanisms involve KIRHLA interactions within the growing fetus, which could contribute to tissue development or defense against infection. NK cells are detectable in fetuses aborted at 624 wk of gestation, pointing to their possible contribution (47). Also of possible relevance, KIR3DL3 transcripts are more abundant in the NK cells of females than males and, although the protein appears undetectable in adult cells, it may function during fetal development (48).
After birth, the favored KIRHLA combinations could improve survival, relative to other combinations, through NK or T cell responses that eliminate infection or cancer, or prevent autoimmune disease. Female specificity could arise in a general way from the hormonal differences between men and women, and their influences on the immune system (49, 50), or more specifically to immune functions under circumstances experienced only by women, such as menstruation, pregnancy, nursing, cancer of breast, or ovary.
Precedent for KIRHLA combinations influencing human reproduction and survival is the work of Hiby et al. (15). They found that inhibitory combinations of fetal HLA-C2 and maternal homozygosity for A KIR haplotypes predispose Caucasians to preeclampsia. These correlations fit well with the observed interactions of fetal trophoblast with maternal NK cells during placentation. Selection by preeclampsia can also explain the inverse correlation between C2 and A haplotype frequencies in human populations, as exemplified by the low C2 and high group A frequencies in the Japanese. In this context, it is important to note that the correlations reported here do not address the fitness of allogeneic combinations of maternal and fetal factors, but of the KIR and HLA genes brought together in the child's genotype. Consequently, the biology underlying the overrepresented and underrepresented KIRHLA combinations we find may well be distinct from those described by Hiby et al. (15).
A signature of natural selection on KIR diversity
KIR-expressing NK cells participate in defense against infection and in reproduction, two functions that are essential for the survival of individuals, populations, and species. Both the KIR and their cognate HLA class I ligands are highly variable. In comparison with Caucasians, the Japanese population has a skewed distribution of KIR and HLA variants, reflecting a distinct history of directional and balancing selection. Functional and genetic study of a Japanese panel provides evidence here that the combination of KIR and HLA variation acts to diversify NK cell repertoire and effector function within the population and to facilitate human survival.
| MATERIALS AND METHODS |
|---|
|
|
|---|
KIR and HLA typing.
KIR genes were typed as described previously (22). 5'RACE used the Advantage 2 PCR kit (CLONTECH Laboratories, Inc.), with the universal primer (UPM) from the SMART-RACE kit or KIR-specific primers as the forward primer combined with KIR-specific reverse primers (Fig. S7, available at http://www.jem.org/cgi/content/full/jem.20051884/DC1). KIR transcripts were cloned into the pGEM T-easy vector (Promega) and sequenced using BigDye terminator 3.1 chemistry and a PRISM 377 DNA sequencer (Applied Biosystems). Sequence assembly and analysis used AlignIR version 2.0 (LICOR). Three or more clones from two or more independent PCR reactions were sequenced to define novel polymorphisms. KIR allele typing by sequence-specific polymorphism PCR used novel primers and those described previously (25, 34, 41, 51) (Figs. S8S10, available at http://www.jem.org/cgi/content/full/jem.20051884/DC1). PCR used hot-start procedures using AmpliTaq FS on a PE9600 thermalcycler (Applied Biosystems). The juxtaposition of 2DL5, 2DS3, and 2DS5 to either 2DL2 or 3DS1 was determined by long-range PCR (52). Exon 1 was sequenced directly from the PCR products to distinguish 2DL5*002 from *005. In exon 6 of 2DL4, the cluster of 9 or 10 adenines (9A/10A) were typed by sequencing (35). HLA-A, B, C typing was by sequencing locus-specific PCR products (minimally exons 2 and 3, but also exon 4 for some samples) with adaptations from Dunn et al. (53) and PCR-SSOP (Sequence-Specific Oligonucleotide Probing), using LABType SSO Typing Tests (One Lambda).
Flow cytometry and NK cell secretion of IFN-
.
KIR on CD56+CD3NK cell surfaces was measured with monoclonal antibodies and flow cytometry (22). Phycoerythrin conjugates of anti-2DL1/2DS1 (EB6; Beckman Coulter), anti-2DL2/2DL3/2DS2 (DX27), and anti-3DL1(DX9) (BD Biosciences), anti-3DL2 (DX31, a gift from Drs. J. Phillips and L. Lanier, DNAX Research Institute, Palo Alto, CA) were used in combination with anti-CD3PerCP (SK7) and anti-CD56fluorescein (NCAM16.2) (BD Biosciences) to stain PBMCs. Three-color flow cytometry used a FACScan instrument and CELLQuest software (BD Biosciences). Parameters measured were the percent NK cells binding an antibody and the mean fluorescence intensity (mfi) for the positive cells.
PBMCs from donors heterozygous for high- and low-binding 3DL1 allotypes were cocultured with the class Ideficient 721.221 cell line or 221 transfected with HLA-B*5801. After gating on 3DL1+ NK cells, IFN-
production was assessed by intracellular staining (54): PBMCs at 6 x 105 cells/well were cocultured with target cells at an optimized effectortarget ratio of 1:1 for 9 h; fluorescent anti-CD3 and anti-CD85PECy5 (GHI/75) (BD Biosciences) were added so that 3DL1+ T cells and the inhibitory effects of LIR1 could be excluded from analysis. Knowing the proportion of donor NK cells expressing each 3DL1 allotype, the inhibitory effect on total NK cells was calculated for each allotype: (% IFN-
inhibition) x (% allotype-expressing NK cells).
Statistical methods.
Reconstruction of allele-level KIR haplotypes used the expectation maximization algorithm (Arlequin version 2.001; reference 55) and a Bayesian statistical method using hidden Monte Carlo Markov Chain modeling (PHASE version 2.1; reference 56). LD was calculated for pairs of KIR alleles (Arlequin version 2.001), D' values >0.5 with P < 0.002 are shown in Fig. S5. The homozygosity statistic F of Ewens (30) and Watterson (31), calculated from KIR allele frequencies was compared with expected homozygosity statistics; significance levels were tested using Slatkin's exact test (57) (Arlequin version 2.001). Tajima's D (32) was calculated for 7-kb haplotypes constructed by combining the coding sequences of KIR alleles on group A haplotypes in order. 10 potential recombination points between haplotypes were first detected by the four-gamete test (58). D values were then calculated in a 300-bp sliding window along the composite haplotypes without extending over the recombination points, and visualized (DnaSP version 4.0; reference 59). For the 9A KIR2DL4 alleles and the 22-bp deletion 2DS4 alleles, each deleted nucleotide was considered an independent position. Haplotype homozygosity was calculated at each gene in group A haplotypes based on Sabeti et al.'s method (33).
Nonparametric tests of significance were used in the analyses described in Figs. 3, 4, 5 and Fig. S4 (two-tailed Mann-Whitney's U-test). Chi-squared tests were used in 2 x 2 contingency tables for pairwise comparisons of genetic associations in Fig. 7. P < 0.05 was considered statistically significant. Fisher's exact test was applied when expected numbers were small (n < 5). Tests used SPSS version 8 software (SPSS Inc). Significance values are as follows: *, P < 0.05; **, P < 0.01; ***, P < 0.005; ****, P < 0.001; and *****, P < 0.0005.
Online supplemental material.
Fig. S1 depicts comparison of KIR allele frequencies between Japanese and Caucasians. Fig. S2 shows kinetics of DX9 binding and phenotype comparison with Z27. Fig. S3 A contains comparison of HLA class I allele distributions between Japanese and Caucasians. Fig. S3 B shows heterozygosity of HLA class I and KIR. Fig. S4 depicts the influence of cognate HLA class I on KIR expression. Fig. S5 displays LD between KIR alleles. Fig. S6 shows the frequency of centromeric and telomeric parts in 44 haplotypes. Fig. S7 contains primers and PCR conditions for KIR cDNA cloning. Fig. S8 depicts primers for KIR allele typing. Fig. S9 shows PCR conditions for KIR allele typing. Fig. S10 depicts primer combinations for KIR allele typing. Online supplemental figures are available at http://www.jem.org/cgi/content/full/jem.20051884/DC1.
| Acknowledgments |
|---|
This work was supported by National Institutes of Health (NIH) grant nos. AI-017892 and AI-022039 (to P. Parham) and a grant from the Leukemia Research Foundation (to M. Yawata).
The authors have no conflicting financial interests.
Submitted: 19 September 2005
Accepted: 1 February 2006
| References |
|---|
|
|
|---|
1 Sun, P.D. 2003. Structure and function of natural-killer-cell receptors. Immunol. Res. 27:539548.[CrossRef][Medline]
2 Abi-Rached, L., and P. Parham. 2005. Natural selection drives recurrent formation of activating killer cell immunoglobulin-like receptor and Ly49 from inhibitory homologues. J. Exp. Med. 201:13191332.
3 Parham, P. 2005. MHC class I molecules and KIRs in human history, health and survival. Nat. Rev. Immunol. 5:201214.[CrossRef][Medline]
4 Tanamachi, D.M., D.C. Moniot, D. Cado, S.D. Liu, J.K. Hsia, and D.H. Raulet. 2004. Genomic Ly49A transgenes: basis of variegated Ly49A gene expression and identification of a critical regulatory element. J. Immunol. 172:10741082.
5 Held, W., B. Kunz, V. Ioannidis, and B. Lowin-Kropf. 1999. Mono-allelic Ly49 NK cell receptor expression. Semin. Immunol. 11:349355.[CrossRef][Medline]
6 Valiante, N.M., M. Uhrberg, H.G. Shilling, K. Lienert-Weidenbach, K.L. Arnett, A. D'Andrea, J.H. Phillips, L.L. Lanier, and P. Parham. 1997. Functionally and structurally distinct NK cell receptor repertoires in the peripheral blood of two human donors. Immunity. 7:739751.[CrossRef][Medline]
7 McVicar, D.W., and D.N. Burshtyn. 2001. Intracellular signaling by the killer immunoglobulin-like receptors and Ly49. Sci. STKE. 2001:RE 1.
8 Anderson, S.K., K. Dewar, M.L. Goulet, G. Leveque, and A.P. Makrigiannis. 2005. Complete elucidation of a minimal class I MHC natural killer cell receptor haplotype. Genes Immun. 6:481492.[CrossRef][Medline]
9 Uhrberg, M., N.M. Valiante, B.P. Shum, H.G. Shilling, K. Lienert-Weidenbach, B. Corliss, D. Tyan, L.L. Lanier, and P. Parham. 1997. Human diversity in killer cell inhibitory receptor genes. Immunity. 7:753763.[CrossRef][Medline]
10 Yawata, M., N. Yawata, L. Abi-Rached, and P. Parham. 2002. Variation within the human killer cell immunoglobulin-like receptor (KIR) gene family. Crit. Rev. Immunol. 22:463482.[Medline]
11 Martin, M.P., X. Gao, J.H. Lee, G.W. Nelson, R. Detels, J.J. Goedert, S. Buchbinder, K. Hoots, D. Vlahov, J. Trowsdale, et al. 2002. Epistatic interaction between KIR3DS1 and HLA-B delays the progression to AIDS. Nat. Genet. 31:429434.[Medline]
12 Khakoo, S.I., C.L. Thio, M.P. Martin, C.R. Brooks, X. Gao, J. Astemborski, J. Cheng, J.J. Goedert, D. Vlahov, M. Hilgartner, et al. 2004. HLA and NK cell inhibitory receptor genes in resolving hepatitis C virus infection. Science. 305:872874.
13 Carrington, M., S. Wang, M.P. Martin, X. Gao, M. Schiffman, J. Cheng, R. Herrero, A.C. Rodriguez, R. Kurman, R. Mortel, et al. 2005. Hierarchy of resistance to cervical neoplasia mediated by combinations of killer immunoglobulin-like receptor and human leukocyte antigen loci. J. Exp. Med. 201:10691075.
14 Nelson, G.W., M.P. Martin, D. Gladman, J. Wade, J. Trowsdale, and M. Carrington. 2004. Cutting edge: heterozygote advantage in autoimmune disease: hierarchy of protection/susceptibility conferred by HLA and killer Ig-like receptor combinations in psoriatic arthritis. J. Immunol. 173:42734276.
15 Hiby, S.E., J.J. Walker, K.M. O'Shaughnessy, C.W. Redman, M. Carrington, J. Trowsdale, and A. Moffett. 2004. Combinations of maternal KIR and fetal HLA-C genes influence the risk of preeclampsia and reproductive success. J. Exp. Med. 200:957965.
16 Shilling, H.G., K.L. McQueen, N.W. Cheng, J.A. Shizuru, R.S. Negrin, and P. Parham. 2003. Reconstitution of NK cell receptor repertoire following HLA-matched hematopoietic cell transplantation. Blood. 101:37303740.
17 Pende, D., R. Biassoni, C. Cantoni, S. Verdiani, M. Falco, C. di Donato, L. Accame, C. Bottino, A. Moretta, and L. Moretta. 1996. The natural killer cell receptor specific for HLA-A allotypes: a novel member of the p58/p70 family of inhibitory receptors that is characterized by three immunoglobulin-like domains and is expressed as a 140-kD disulphide-linked dimer. J. Exp. Med. 184:505518.
18 Litwin, V., J. Gumperz, P. Parham, J.H. Phillips, and L.L. Lanier. 1994. NKB1: a natural killer cell receptor involved in the recognition of polymorphic HLA-B molecules. J. Exp. Med. 180:537543.
19 Winter, C.C., J.E. Gumperz, P. Parham, E.O. Long, and N. Wagtmann. 1998. Direct binding and functional transfer of NK cell inhibitory receptors reveal novel patterns of HLA-C allotype recognition. J. Immunol. 161:571577.
20 Rajagopalan, S., Y.T. Bryceson, S.P. Kuppusamy, D.E. Geraghty, A. van der Meer, I. Joosten, and E.O. Long. 2005. Activation of NK cells by an endocytosed receptor for soluble HLA-G. PLoS Biol. DOI:10.1371/journal.pbio.0040009.
21 Shilling, H.G., N. Young, L.A. Guethlein, N.W. Cheng, C.M. Gardiner, D. Tyan, and P. Parham. 2002. Genetic control of human NK cell repertoire. J. Immunol. 169:239247.
22 Yawata, M., N. Yawata, K.L. McQueen, N.W. Cheng, L.A. Guethlein, R. Rajalingam, H.G. Shilling, and P. Parham. 2002. Predominance of group A KIR haplotypes in Japanese associated with diverse NK cell repertoires of KIR expression. Immunogenetics. 54:543550.[CrossRef][Medline]
23 Whang, D.H., H. Park, J.A. Yoon, and M.H. Park. 2005. Haplotype analysis of killer cell immunoglobulin-like receptor genes in 77 Korean families. Hum. Immunol. 66:146154.[CrossRef][Medline]
24 Jiang, K., F.M. Zhu, Q.F. Lv, and L.X. Yan. 2005. Distribution of killer cell immunoglobulin-like receptor genes in the Chinese Han population. Tissue Antigens. 65:556563.[CrossRef][Medline]
25 Gardiner, C.M., L.A. Guethlein, H.G. Shilling, M. Pando, W.H. Carr, R. Rajalingam, C. Vilches, and P. Parham. 2001. Different NK cell surface phenotypes defined by the DX9 antibody are due to KIR3DL1 gene polymorphism. J. Immunol. 166:29923001.
26 Gumperz, J.E., N.M. Valiante, P. Parham, L.L. Lanier, and D. Tyan. 1996. Heterogeneous phenotypes of expression of the NKB1 natural killer cell class I receptor among individuals of different human histocompatibility leukocyte antigens types appear genetically regulated, but not linked to major histocompatibililty complex haplotype. J. Exp. Med. 183:18171827.
27 Carr, W.H., M.J. Pando, and P. Parham. 2005. KIR3DL1 polymorphisms that affect NK cell inhibition by HLA-Bw4 ligand. J. Immunol. 175:52225229.
28 Tokunaga, K., Y. Ishikawa, A. Ogawa, H. Wang, S. Mitsunaga, S. Moriyama, L. Lin, M. Bannai, Y. Watanabe, K. Kashiwase, et al. 1997. Sequence-based association analysis of HLA class I and II alleles in Japanese supports conservation of common haplotypes. Immunogenetics. 46:199205.[CrossRef][Medline]
29 Itoh, Y., N. Mizuki, T. Shimada, F. Azuma, M. Itakura, K. Kashiwase, E. Kikkawa, J.K. Kulski, M. Satake, and H. Inoko. 2005. High-throughput DNA typing of HLA-A, -B, -C, and -DRB1 loci by a PCR-SSOP-Luminex method in the Japanese population. Immunogenetics. 57:717729.[CrossRef][Medline]
30 Ewens, W.J. 1972. The sampling theory of selectively neutral alleles. Theor. Popul. Biol. 3:87112.[CrossRef][Medline]
31 Watterson, G. 1978. The homozygosity test of neutrality. Genetics. 88:405417.
32 Tajima, F. 1989. Statistical method for testing the neutral mutation hypothesis by DNA polymorphism. Genetics. 123:585595.
33 Sabeti, P.C., D.E. Reich, J.M. Higgins, H.Z. Levine, D.J. Richter, S.F. Schaffner, S.B. Gabriel, J.V. Platko, N.J. Patterson, G.J. McDonald, et al. 2002. Detecting recent positive selection in the human genome from haplotype structure. Nature. 419:832837.[CrossRef][Medline]
34 Shilling, H.G., L.A. Guethlein, N.W. Cheng, C.M. Gardiner, R. Rodriguez, D. Tyan, and P. Parham. 2002. Allelic polymorphism synergizes with variable gene content to individualize human KIR genotype. J. Immunol. 168:23072315.
35 Witt, C.S., A. Martin, and F.T. Christiansen. 2000. Detection of KIR2DL4 alleles by sequencing and SSCP reveals a common allele with a shortened cytoplasmic tail. Tissue Antigens. 56:248257.[CrossRef][Medline]
36 Nakajima, F., J. Nakamura, and T. Yokota. 2002. Analysis of HLA haplotypes in Japanese, using high resolution allele typing. MHC. 8:132.
37 Fahlen, L., U. Lendahl, and C.L. Sentman. 2001. MHC class I-Ly49 interactions shape the Ly49 repertoire on murine NK cells. J. Immunol. 166:65856592.
38 Hanke, T., H. Takizawa, and D.H. Raulet. 2001. MHC-dependent shaping of the inhibitory Ly49 receptor repertoire on NK cells: evidence for a regulated sequential model. Eur. J. Immunol. 31:33703379.[CrossRef][Medline]
39 Dorfman, J.R., and D.H. Raulet. 1998. Acquisition of Ly49 receptor expression by developing natural killer cells. J. Exp. Med. 187:609618.
40 Williams, N.S., A. Kubota, M. Bennett, V. Kumar, and F. Takei. 2000. Clonal analysis of NK cell development from bone marrow progenitors in vitro: orderly acquisition of receptor gene expression. Eur. J. Immunol. 30:20742082.[CrossRef][Medline]
41 Norman, P.J., M.A. Cook, B.S. Carey, C.V. Carrington, D.H. Verity, K. Hameed, D.D. Ramdath, D. Chandanayingyong, M. Leppert, H.A. Stephens, and R.W. Vaughan. 2004. SNP haplotypes and allele frequencies show evidence for disruptive and balancing selection in the human leukocyte receptor complex. Immunogenetics. 56:225237.[Medline]
42 Reusch, T.B., M.A. Haberli, P.B. Aeschlimann, and M. Milinski. 2001. Female sticklebacks count alleles in a strategy of sexual selection explaining MHC polymorphism. Nature. 414:300302.[CrossRef][Medline]
43 Ziegler, A., H. Kentenich, and B. Uchanska-Ziegler. 2005. Female choice and the MHC. Trends Immunol. 26:496502.[CrossRef][Medline]
44 Ober, C., L.R. Weitkamp, N. Cox, H. Dytch, D. Kostyu, and S. Elias. 1997. HLA and mate choice in humans. Am. J. Hum. Genet. 61:497504.[CrossRef][Medline]
45 Vatten, L.J., and R. Skjaerven. 2004. Offspring sex and pregnancy outcome by length of gestation. Early Hum. Dev. 76:4754.[CrossRef][Medline]
46 Eiben, B., I. Bartels, S. Bahr-Porsch, S. Borgmann, G. Gatz, G. Gellert, R. Goebel, W. Hammans, M. Hentemann, R. Osmers, et al. 1990. Cytogenetic analysis of 750 spontaneous abortions with the direct-preparation method of chorionic villi and its implications for studying genetic causes of pregnancy wastage. Am. J. Hum. Genet. 47:656663.[Medline]
47 Phillips, J.H., T. Hori, A. Nagler, N. Bhat, H. Spits, and L.L. Lanier. 1992. Ontogeny of human natural killer (NK) cells: fetal NK cells mediate cytolytic function and express cytoplasmic CD3
,
proteins. J. Exp. Med. 175:10551066.
48 Trundley, A.E., S.E. Hiby, C. Chang, A.M. Sharkey, S. Santourlidis, M. Uhrberg, J. Trowsdale, and A. Moffett. 2006. Molecular characterization of KIR3DL3. Immunogenetics. 57:904916.[CrossRef][Medline]
49 Da Silva, J.A. 1999. Sex hormones and glucocorticoids: interactions with the immune system. Ann. NY Acad. Sci. 876:102118.[CrossRef][Medline]
50 Tanriverdi, F., L.F. Silveira, G.S. MacColl, and P.M. Bouloux. 2003. The hypothalamic-pituitary-gonadal axis: immune function and autoimmunity. J. Endocrinol. 176:293304.[Abstract]
51 Gomez-Lozano, N., and C. Vilches. 2002. Genotyping of human killer-cell immunoglobulin-like receptor genes by polymerase chain reaction with sequence-specific primers: an update. Tissue Antigens. 59:184193.[CrossRef][Medline]
52 Vilches, C., C.M. Gardiner, and P. Parham. 2000. Gene structure and promoter variation of expressed and nonexpressed variants of the KIR2DL5 gene. J. Immunol. 165:64166421.
53 Dunn, P.P., V. Carter, A. Dunn, S. Day, S.V. Fuggle, J. Ross, and G. Cavanagh. 2000. Identification of an HLA-B7 serological variant and its characterization by sequencing based typing. Tissue Antigens. 55:7173.[CrossRef][Medline]
54 Draghi, M., N. Yawata, M. Gleimer, M. Yawata, N.M. Valiante, and P. Parham. 2005. Single-cell analysis of the human NK cell response to missing self and its inhibition by HLA class I. Blood. 105:20282035.
55 Schneider, S., D. Roessli, and L. Excoffier. 2000. Arlequin ver. 2.000: A Software for Population Genetics Data analysis. Genetics and Biometry Laboratory, University of Geneva, Geneva. 111 pp.
56 Stephens, M., N.J. Smith, and P. Donnelly. 2001. A new statistical method for haplotype reconstruction from population data. Am. J. Hum. Genet. 68:978989.[CrossRef][Medline]
57 Slatkin, M. 1996. A correction to the exact test based on the Ewens sampling distribution. Genet. Res. 68:259260.[Medline]
58 Kaplan, N., and R.R. Hudson. 1985. The use of sample genealogies for studying a selectively neutral m-loci model with recombination. Theor. Popul. Biol. 28:382396.[CrossRef][Medline]
59 Rozas, J., J.C. Sanchez-DelBarrio, X. Messeguer, and R. Rozas. 2003. DnaSP, DNA polymorphism analyses by the coalescent and other methods. Bioinformatics. 19:24962497.
This article has been cited by other articles:
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| TABLE OF CONTENTS |
|