 |
Introduction
|
|---|
In humans, Ig gene recombination produces large numbers of self-reactive antibodies or B cell receptors (BCRs; reference 1). Most of the polyreactive antibodies and antinuclear antibodies (ANAs) are removed from the repertoire during B cell development, thereby ensuring self-tolerance (1). In mice, three mechanisms account for the silencing of newly arising autoreactive B cells: deletion, anergy, and receptor editing (25). These tolerance mechanisms are triggered and regulated by antigen binding to self-reactive BCRs. For example, transgenic and knockout mouse experiments have shown that BCR signaling thresholds are essential in B cell tolerance (6). Changes in tuning functions of the BCR coreceptors such as CD19 or CD22 and PD-1 and their associated signaling molecules Lyn and SHIP all impact on the tolerance response (710). Much less is known about the mechanisms that regulate B cell tolerance in humans.
Defects in BCR signaling have been reported in B cells from immunodeficient patients with common variable immunodeficiency who frequently develop autoimmunity, suggesting that BCR signaling may play an important role in counterselecting self-reactive B cells (11). To investigate the role of BCR signaling in the regulation of autoreactive B cells in humans, we analyzed tolerance in B cells from X-linked agammaglobulinemia (XLA) patients. XLA or Bruton's disease is characterized by a severe decrease of peripheral B cells and serum Ig (12, 13). Genetic studies in humans led to the identification of the defective gene, named Bruton's tyrosine kinase (BTK) gene, which encodes a cytoplasmic tyrosine kinase that plays an essential role in mediating BCR signaling (14, 15). Although B cell differentiation is severely affected at the pro- to pre-B transition, a few B cells develop and migrate to the periphery where they fail to accumulate (12, 16, 17). XLA has a more severe phenotype in humans than murine Xid, which results from loss of function of the murine btk gene (18). In btk/ mice, peripheral B cells are observed but responses to T-independent antigen (type II) are impaired, whereas responses to T-dependent antigens remain normal (19). Therefore, mouse models for Btk deficiency cannot be extrapolated to humans. We report that in humans, central B cell tolerance checkpoints are abrogated in the absence of Btk.
 |
Materials and Methods
|
|---|
Patients.
Patients 1 and 2 are adult first cousins who suffer from a mutation in exon 11 of the BTK gene consisting of an 18-bp insertion (XLA-Ins) resulting from the duplication of neighboring DNA. Patients 3 and 4 are adolescent and preadolescent brothers who show an adenosine to cytidine substitution in codon 117 that results in a proline instead of the wild-type threonine in the pleckstrin homology domain of Btk (XLA-T117P). All patients showed similarly decreased levels of peripheral B cells that were mostly CD19+ CD10+ IgM+ CD27 new emigrant B cells. Control healthy donors were a 23-yr-old female (JH) and a 31-yr-old male (PE). All samples were collected after signed informed consent in accordance with IRB-reviewed protocols.
Single Cell Sorting.
Peripheral B cells were purified from the blood of XLA patients and from the blood of two nonrelated healthy donors by negative selection using the RosetteSep procedure (StemCell Technologies, Inc.). Enriched B cells were stained with FITC antihuman CD27, PE antihuman CD10, antihuman IgM-biotin, and allophycocyanin anti-CD19 (BD Biosciences and Becton Dickinson). Biotinylated antibodies were revealed using Streptavidin-Red613 (GIBCO BRL). Single CD19+ CD10+ IgM+ CD27 new emigrant B cells from XLA patients and control donors were sorted on a FACSVantage (Becton Dickinson) into 96-well PCR plates containing 4 µl of lysis solution (0.5x PBS containing 10 mM DTT, 8 U RNAsin [Promega], and 0.4 U 5'-3' RNase Inhibitor [Eppendorf]) and immediately frozen on dry ice. All samples were stored at 70°C.
cDNA, RT-PCR, Antibody Production, and Purification.
RNA from single cells was reverse transcribed in the original 96-well plate in 12.5 µl of reactions containing 100 U Superscript II RT (GIBCO BRL) for 45 min at 37°C. RT-PCR reactions, primer sequences, cloning strategy, expression vectors, antibody expression, and purification were as described previously (1). Ig sequences were analyzed by Ig BLAST comparison with GenBank.
ELISAs and Immunofluorescence Assays.
Antibody concentration, reactivity against specific antigens, and indirect immunofluorescence were as described previously (1). High (polyreactive ED38) and weak (mGO186) ANA-reactive and -nonreactive mGO53 and iGO13 were used as positive and negative controls in self-reactivity and polyreactivity ELISAs (1, 20).
Statistical Analysis.
Two-tailed p-values were calculated by the Fisher Exact Test. Bonferroni corrections were used when analyzing unpredictable D gene usage frequency by multiplying the p-value by the number of parameters. Although some data from individual patients could reach statistical significance, the frequency of self-reactive clones was calculated after pooling data from patients carrying the same BTK gene mutation. Because of the very large number of Ig gene segments, antibody repertoire analyses were performed after pooling Ig sequences from all XLA patients.
Online Supplemental Material.
Antibody characteristics from control new emigrant, XLA-Ins, and XLA-T117P B cells are presented in Tables S1S3. Fig. S1 shows antibody features that differ between nonreactive and polyreactive antibodies from XLA B cells. Tables S1S3 and Fig. S1 are available at http://www.jem.org/cgi/content/full/jem.20040920/DC1.
 |
Results
|
|---|
Peripheral B Cell Selection in XLA Patients.
BTK gene encodes a cytoplasmic tyrosine kinase that plays an essential role in BCR signaling in humans (14, 15, 21, 22). XLA patients are characterized by a severe decrease in peripheral B cells and serum Ig levels (12, 13). In line with this observation, we found that most peripheral blood B cells from XLA patients were CD19+ CD10+ IgM+ CD27 new emigrant B cells that fail to develop into CD19+ CD10 IgM+ CD27 mature naive B cells (Fig. 1; reference 23).
The authors have no conflicting financial interests.
1 Wardemann, H., S. Yurasov, A. Schaefer, J.W. Young, E. Meffre, and M.C. Nussenzweig. 2003. Predominant autoantibody production by early human B cell precursors. Science. 301:13741377.[Abstract/Free Full Text]
2 Nemazee, D.A., and K. Bürki. 1989. Clonal deletion of B lymphocytes in a transgenic mouse bearing anti-MHC class I antibody genes. Nature. 337:562566.[CrossRef][Medline]
3 Goodnow, C.C., J. Crosbie, S. Adelstein, T.B. Lavoie, S.J. Smith-Gill, R.A. Brink, H. Pritchard-Briscoe, J.S. Wotherspoon, R.H. Loblay, K. Raphael, et al. 1988. Altered immunoglobulin expression and functional silencing of self-reactive B lymphocytes in transgenic mice. Nature. 334:676682.[CrossRef][Medline]
4 Tiegs, S.L., D.M. Russell, and D. Nemazee. 1993. Receptor editing in self-reactive bone marrow B cells. J. Exp. Med. 177:10091020.[Abstract/Free Full Text]
5 Gay, D., T. Saunders, S. Camper, and M. Weigert. 1993. Receptor editing: an approach by autoreactive B cells to escape tolerance. J. Exp. Med. 177:9991008.[Abstract/Free Full Text]
6 Goodnow, C.C. 1996. Balancing immunity and tolerance: deleting and tuning lymphocyte repertoires. Proc. Natl. Acad. Sci. USA. 93:22642271.[Abstract/Free Full Text]
7 Tedder, T.F., M. Inaoki, and S. Sato. 1997. The CD19-CD21 complex regulates signal transduction thresholds governing humoral immunity and autoimmunity. Immunity. 6:107118.[CrossRef][Medline]
8 Cornall, R.J., J.G. Cyster, M.L. Hibbs, A.R. Dunn, K.L. Otipoby, E.A. Clark, and C.C. Goodnow. 1998. Polygenic autoimmune traits: Lyn, CD22, and SHP-1 are limiting elements of a biochemical pathway regulating BCR signaling and selection. Immunity. 8:497508.[CrossRef][Medline]
9 Nishimura, H., M. Nose, H. Hiai, N. Minato, and T. Honjo. 1999. Development of lupus-like autoimmune diseases by disruption of the PD-1 gene encoding an ITIM motif-carrying immunoreceptor. Immunity. 11:141151.[CrossRef][Medline]
10 Okazaki, T., A. Maeda, H. Nishimura, T. Kurosaki, and T. Honjo. 2001. PD-1 immunoreceptor inhibits B cell receptor-mediated signaling by recruiting src homology 2-domain-containing tyrosine phosphatase 2 to phosphotyrosine. Proc. Natl. Acad. Sci. USA. 98:1386613871.[Abstract/Free Full Text]
11 Cunningham-Rundles, C., and C. Bodian. 1999. Common variable immunodeficiency: clinical and immunological features of 248 patients. Clin. Immunol. 92:3448.[CrossRef][Medline]
12 Conley, M.E. 1985. B cells in patients with X-linked agammaglobulinemia. J. Immunol. 134:30703074.[Abstract]
13 Rosen, F.S., M.D. Cooper, and R.J. Wedgwood. 1995. The primary immunodeficiencies. N. Engl. J. Med. 333:431440.[Free Full Text]
14 de Weers, M., G.S. Brouns, S. Hinshelwood, C. Kinnon, R.K. Schuurman, R.W. Hendriks, and J. Borst. 1994. B-cell antigen receptor stimulation activates the human Bruton's tyrosine kinase, which is deficient in X-linked agammaglobulinemia. J. Biol. Chem. 269:2385723860.[Abstract/Free Full Text]
15 Kurosaki, T., and S. Tsukada. 2000. BLNK: connecting Syk and Btk to calcium signals. Immunity. 12:15.[CrossRef][Medline]
16 Campana, D., J. Farrant, N. Inamdar, A.D. Webster, and G. Janossy. 1990. Phenotypic features and proliferative activity of B cell progenitors in X-linked agammaglobulinemia. J. Immunol. 145:16751680.[Abstract]
17 Meffre, E., F. LeDeist, G. de Saint-Basile, A. Deville, M. Fougereau, A. Fischer, and C. Schiff. 1997. A non-XLA primary deficiency causes the earliest known defect of B cell differentiation in humans: a comparison with an XLA case. Immunol. Lett. 57:9399.[CrossRef][Medline]
18 Kinnon, C., S. Hinshelwood, R.J. Levinsky, and R.C. Lovering. 1993. X-linked agammaglobulinemiagene cloning and future prospects. Immunol. Today. 14:554558.[CrossRef][Medline]
19 Khan, W.N., F.W. Alt, R.M. Gerstein, B.A. Malynn, I. Larsson, G. Rathbun, L. Davidson, S. Muller, A.B. Kantor, L.A. Herzenberg, et al. 1995. Defective B cell development and function in Btk-deficient mice. Immunity. 3:283299.[CrossRef][Medline]
20 Meffre, E., A. Schaefer, H. Wardemann, P. Wilson, E. Davis, and M.C. Nussenzweig. 2004. Surrogate light chainexpressing human peripheral B cells produce self-reactive antibodies. J. Exp. Med. 199:145150.[Abstract/Free Full Text]
21 Vetrie, D., I. Vorechovsky, P. Sideras, J. Holland, A. Davies, F. Flinter, L. Hammarstrom, C. Kinnon, R. Levinsky, M. Bobrow, et al. 1993. The gene involved in X-linked agammaglobulinaemia is a member of the src family of protein-tyrosine kinases. Nature. 361:226233.[CrossRef][Medline]
22 Tsukada, S., D.C. Saffran, D.J. Rawlings, O. Parolini, R.C. Allen, I. Klisak, R.S. Sparkes, H. Kubagawa, T. Mohandas, S. Quan, et al. 1993. Deficient expression of a B cell cytoplasmic tyrosine kinase in human X-linked agammaglobulinemia. Cell. 72:279290.[CrossRef][Medline]
23 Meffre, E., F. Papavasiliou, P. Cohen, O. de Bouteiller, D. Bell, H. Karasuyama, C. Schiff, J. Banchereau, Y.J. Liu, and M.C. Nussenzweig. 1998. Antigen receptor engagement turns off the V(D)J recombination machinery in human tonsil B cells. J. Exp. Med. 188:765772.[Abstract/Free Full Text]
24 Pascual, V., K. Victor, D. Lelsz, M.B. Spellerberg, T.J. Hamblin, K.M. Thompson, I. Randen, J. Natvig, J.D. Capra, and F.K. Stevenson. 1991. Nucleotide sequence analysis of the V regions of two IgM cold agglutinins. Evidence that the VH4-21 gene segment is responsible for the major cross-reactive idiotype. J. Immunol. 146:43854391.[Abstract]
25 Silberstein, L.E., L.C. Jefferies, J. Goldman, D. Friedman, J.S. Moore, P.C. Nowell, D. Roelcke, W. Pruzanski, J. Roudier, and G.J. Silverman. 1991. Variable region gene analysis of pathologic human autoantibodies to the related i and I red blood cell antigens. Blood. 78:23722386.[Abstract/Free Full Text]
26 Meffre, E., M. Milili, C. Blanco-Betancourt, H. Antunes, M.C. Nussenzweig, and C. Schiff. 2001. Immunoglobulin heavy chain expression shapes the B cell receptor repertoire in human B cell development. J. Clin. Invest. 108:879886.[CrossRef][Medline]
27 Corbett, S.J., I.M. Tomlinson, E.L.L. Sonnhammer, D. Buck, and G. Winter. 1997. Sequence of the human immunoglobulin diversity (D) segment locus: a systematic analysis provides no evidence for the use of DIR segments, inverted D segments, "minor" D segments or D-D recombination. J. Mol. Biol. 270:587597.[CrossRef][Medline]
28 Meffre, E., E. Davis, C. Schiff, C. Cunningham-Rundles, L.B. Ivashkiv, L.M. Staudt, J.W. Young, and M.C. Nussenzweig. 2000. Circulating human B cells that express surrogate light chains and edited receptors. Nat. Immunol. 1:207213.[CrossRef][Medline]
29 Zheng, N.-Y., K. Wilson, X. Wang, A. Boston, G. Kolar, S.M. Jackson, Y.-J. Liu, V. Pascual, J.D. Capra, and P. Wilson. 2004. Human immunoglobulin selection associated with class switch and possible tolerogenic origins for C
class-switched B cells. J. Clin. Invest. 113:11881201.[CrossRef][Medline]
30 Hieter, P.A., S.J. Korsmeyer, T.A. Waldmann, and P. Leder. 1981. Human immunoglobulin kappa light-chain genes are deleted or rearranged in lambda-producing B cells. Nature. 290:368372.[CrossRef][Medline]
31 Barbas, S.M., H.J. Ditzel, E.M. Salonen, W.P. Yang, G.J. Silverman, and D.R. Burton. 1995. Human autoantibody recognition of DNA. Proc. Natl. Acad. Sci. USA. 92:25292533.[Abstract/Free Full Text]
32 Radic, M.Z., J. Mackle, J. Erikson, C. Mol, W.F. Anderson, and M. Weigert. 1993. Residues that mediate DNA binding of autoimmune antibodies. J. Immunol. 150:49664977.[Abstract]
33 Klonowski, K.D., L.L. Primiano, and M. Monestier. 1999. Atypical VH-D-JH rearrangements in newborn autoimmune MRL mice. J. Immunol. 162:15661572.[Abstract/Free Full Text]
34 Shiokawa, S., F. Mortari, J.O. Lima, C. Nunez, F.E. Bertrand III, P.M. Kirkham, S. Zhu, A.P. Dasanayake, and H.W. Schroeder Jr. 1999. IgM heavy chain complementarity-determining region 3 diversity is constrained by genetic and somatic mechanisms until two months after birth. J. Immunol. 162:60606070.[Abstract/Free Full Text]
35 Lam, K.P., R. Kuhn, and K. Rajewsky. 1997. In vivo ablation of surface immunoglobulin on mature B cells by inducible gene targeting results in rapid cell death. Cell. 90:10731083.[CrossRef][Medline]
36 Meffre, E., and M.C. Nussenzweig. 2002. Deletion of immunoglobulin beta in developing B cells leads to cell death. Proc. Natl. Acad. Sci. USA. 99:1133411339.[Abstract/Free Full Text]
37 Middendorp, S., and R.W. Hendriks. 2004. Cellular maturation defects in Bruton's tyrosine kinase-deficient immature B cells are amplified by premature B cell receptor expression and reduced by receptor editing. J. Immunol. 172:13711379.[Abstract/Free Full Text]
38 Mahajan, S., S. Ghosh, E.A. Sudbeck, Y. Zheng, S. Downs, M. Hupke, and F.M. Uckun. 1999. Rational design and synthesis of a novel anti-leukemic agent targeting Bruton's tyrosine kinase (BTK), LFM-A13 [
-Cyano-ß-hydroxy-ß-methyl-N-(2,5-dibromophenyl) propenamide]. J. Biol. Chem. 274:95879599.[Abstract/Free Full Text]
39 Prak, E.L., and M. Weigert. 1995. Light chain replacement: a new model for antibody gene rearrangement. J. Exp. Med. 182:541548.[Abstract/Free Full Text]
40 Timmers, E., M.M. Hermans, M.E. Kraakman, R.W. Hendriks, and R.K. Schuurman. 1993. Diversity of immunoglobulin kappa light chain gene rearrangements and evidence of somatic mutation in V kappa IV family gene segments in X-linked agammaglobulinemia. Eur. J. Immunol. 23:619624.[Medline]
41 Ellmeier, W., S. Jung, M.J. Sunshine, F. Hatam, Y. Xu, D. Baltimore, H. Mano, and D.R. Littman. 2000. Severe B cell deficiency in mice lacking the Tec kinase family members Tec and Btk. J. Exp. Med. 192:16111623.[Abstract/Free Full Text]
42 Dingjan, G., S. Middendorp, K. Dahlenborg, A. Maas, F. Grosveld, and R.W. Hendriks. 2001. Bruton's tyrosine kinase regulates the activation of gene rearrangements at the
light chain locus in precursor B cells in the mouse. J. Exp. Med. 193:11691178.[Abstract/Free Full Text]
43 Braun, U., K. Rajewsky, and R. Pelanda. 2000. Different sensitivity to receptor editing of B cells from mice hemizygous or homozygous for targeted Ig transgenes. Proc. Natl. Acad. Sci. USA. 97:74297434.[Abstract/Free Full Text]
44 Kouskoff, V., G. Lacaud, K. Pape, M. Retter, and D. Nemazee. 2000. B cell receptor expression level determines the fate of developing B lymphocytes: receptor editing versus selection. Proc. Natl. Acad. Sci. USA. 97:74357439.[Abstract/Free Full Text]
45 Casellas, R., T.A. Shih, M. Kleinewietfeld, J. Rakonjac, D. Nemazee, K. Rajewsky, and M.C. Nussenzweig. 2001. Contribution of receptor editing to the antibody repertoire. Science. 291:15411544.[Abstract/Free Full Text]
46 Tze, L.E., K.L. Hippen, and T.W. Behrens. 2003. Late immature B cells (IgMhigh IgDneg) undergo a light chain receptor editing response to soluble self-antigen. J. Immunol. 171:678682.[Abstract/Free Full Text]
47 Martin, S., D. Wolf-Eichbaum, G. Duinkerken, W.A. Sherbaum, H. Kolb, J.G. Noordzij, and B.O. Roep. 2001. Development of type I diabetes despite severe hereditary B-cell deficiency. N. Engl. J. Med. 345:10361040.[Free Full Text]
48 Sakaguchi, N., T. Takahashi, H. Hata, T. Nomura, T. Tagami, S. Yamazaki, T. Sakihama, T. Matsutani, I. Negishi, S. Nakatsuru, and S. Sakaguchi. 2003. Altered thymic T-cell selection due to a mutation of the ZAP-70 gene causes autoimmune arthritis in mice. Nature. 426:454460.[CrossRef][Medline]