The T lymphocyte response to syngeneic λ2 light chain idiotopes. Significance of individual amino acids revealed by variant λ2 chains and idiotope-mimicking chemically synthesized peptides
✍ Scribed by Kristian Hannestad; Gunn Kristoffersen; Jean Paul Briand
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- English
- Weight
- 571 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0014-2980
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✦ Synopsis
In the present study we have investigated the structure of the helper T cell (Th)defined idiotope (Id) of myeloma protein 315 h2 light chain (u315) in BALB/c (H-2d) mice which carry a high-responder immune response gene for this Id. Three eptides were synthesized which spanned the third hypervariable region (HV3) of h2"': peptides 88-99,94-108 and 91-108. Only peptide 91-108 was capable of eliciting carrierspecific Th that recognized M315 or free hZ3l5. These Th did not recognize hZs7 chain which differs from hZ3l5 at 4 positions in this region; these are Tyr94, Ser95, Thr96, Tyr9* for h2'-' and Phe94, Arg9', Phe9' for hZ3l5. Immunization with peptide analogues revealed that substitution of Tyr for Phe94 was compatible with Id-h2315 mimicry, but substitution of Ser for Arg9' or Thr for nized Id. Furthermore, Th primed with h25-7 chain did not cross-react with h2T9 ; these h2 chains only differ from each other at positions 98 and 99 at the Vh2-Jh2 junction. The data indicate that individual amino acids of short peptide segments are critical for Th-recognized Id of the h2 HV3 loop and Vh2-Jh2 junction. Furthermore, the immunogenicity of a small peptide suggests that the carrier (h2)-specific Th recognize Id that have been processed by antigen-presenting cells (APC). This implies the existence of two categories of "internal images" of foreign or of self antigens: (a) serologically defined and (b) T lymphocyte defined. We propose that as a rule, Id processing by APC, including B cells, destroys the first and reveals the second category. The possible physiological function of these Id-specific T cells in network interactions with B cells is discussed. destroyed the Th-reco 54-