Journal of Experimental Medicine, Vol 156, 539-549, Copyright © 1982 by Rockefeller University Press
Regulatory idiotypes. T helper cells recognize a shared VH idiotope on phosphorylcholine-specific antibodies
K Gleason and H Kohler
Priming of BALB/c mice with phosphorylcholine-hemocyanin (PC-Hy) induces T
helper cells that are detected in splenic fragment cultures responding to
immunization with trinitrophenylated PC-binding myeloma proteins, TEPC 15
(TNP-T15) and MOPC 167 (TNP-M167). Trinitrophenylation did not alter the
binding site, idiotype, or isotype of the antibodies as demonstrated by
binding studies. To assay idiotype-recognizing helper cells,
Ly-2.2-depleted T cells from PC-Hy- primed donor mice were transferred to
syngeneic athymic mice. Splenic anti-trinitrophenol fragment cultures were
prepared from the nude recipients, and the response to TNP-T15 and TNP-M167
was measured by enzyme-linked immunosorbent assay. The number of responding
fragments is dependent on the number of transferred primed T cells. The
homing efficiency of 51Cr-labeled helper cells into the spleen of nude
recipients was determined. The frequencies of T helper cells taken from
PC-Hy-primed donors required for a B cell response to TNP-T15 or TNP- M167
were indistinguishable. The fine specificity of the anti-PC
idiotype-recognizing T helper cells was studied by adding hapten (PC) or
unconjugated myeloma proteins to fragment cultures as inhibitors at the
time of immunization. PC and PC-bovine serum albumin, as well as T15 and
M167, inhibited the helper function in vitro. Furthermore, free heavy
chains of T15 and M167 partially inhibited T help, but free light chains of
both idiotypes had no effect. These findings collectively show that T
helper cells, induced by priming with antigen, recognize a shared idiotypic
determination on T15 and M167 that is part of the PC binding site. The
heavy chains of T15 and M167 appears to be the major structural component
of this determinant. Evidently, T helper cells can recognize a shared
determinant that is present on idiotypically different myeloma proteins.
This determinant appears to be conserved throughout evolutionary and
somatic mutations. The role of this shared, binding site-related idiotypic
determinant as a regulatory idiotype in T-B cell interaction is discussed.