In:
European Journal of Immunology, Wiley, Vol. 23, No. 10 ( 1993-10), p. 2655-2660
Kurzfassung:
We have previously reported that γ2a b /I‐A d ‐specific Th1 clones from BALB/c mice (γ2a a , H‐2 d ) mediated a long‐lasting, selective suppression of serum IgG2a b levels when transferred to newborn (BALB/c X B10.D2)F 1 (γ2 a/b , H‐2 d ) mice (Bartnes, K. and Hannestad, K. Eur. J. Immunol. 1991. 21 : 2365). We here analyze the peptide specificity of hybridomas derived from two suppressive T cell clones. The shortest synthetic peptide with optimal antigenicity comprises γ2a b residues 435–451 (Kabat numbering). The determinant core encompasses the γ2a b 440–446 (KLRVQKS) sequence which contains an I‐A d allele‐specific motif. Challenge with single amino acid‐substituted γ2a b 435–447 analogs revealed that residues K 440 , R 442 and K 445 which are shared by the autologous and allogeneic γ2a, as well as residues Q 444 and S 446 which represent allogeneic differences, are critical for recognition. We obtained evidence that K 440 , R 442 and Q 444 are epitope residues, while K 445 and S 446 contribute to anchoring of the peptide to I‐A d . Amino acids located outside of the core also influence antigenicity, the most striking effect being a 340–870‐fold augmentation of potency when γ2a b 437–451 is extended by F 436 . IgG2a b required processing in order to stimulate the hybridomas. The data support the contention that the Th1 clones specific for Fc of γ2a b mediated IgG2a b suppression by cognate interaction with sIgG2a b+ B cells that presented a Cγ2a b peptide(s) derived from their endogenous Ig on major histocompatibility complex class II. The T cells cross‐reacted weakly with peptide 435–451 of the autologous γ2a a allotype. This opens the possibility that self‐peptides from Ig C regions can target B cells for regulatory interactions with autologous Th cells.
Materialart:
Online-Ressource
ISSN:
0014-2980
,
1521-4141
DOI:
10.1002/eji.1830231040
Sprache:
Englisch
Verlag:
Wiley
Publikationsdatum:
1993
ZDB Id:
1491907-2
