Immune responses against self-TCR peptides

Area of Science:

• Immunology
• T-cell receptor (TCR) research
• Autoimmune disease mechanisms

Background:

• Experimental autoimmune encephalomyelitis (EAE) is an autoimmune disease model.
• Vaccination against T-cell receptor (TCR) peptide V beta 8.2 (39-59) has been suggested to inhibit EAE.
• Understanding immune responses to TCR peptides is crucial for autoimmune disease research.

Purpose of the Study:

• To analyze the immune response to TCR peptide V beta 8.2 (39-59) and related peptides.
• To investigate the immunogenicity and cross-reactivity of TCR peptides in different rat strains and mice.
• To determine if lymphocytes responding to V beta 8.2 (39-59) are responsible for EAE inhibition.

Main Methods:

• In vivo immunization and in vitro lymphocyte proliferation assays.
• Comparison of immunogenicity between rat and mouse TCR peptide homologs.
• Genetic analysis of immune responses in different rat strains and hybrids.
• Testing responses of sensitized cells and cell lines to T cells expressing V beta 8.2.

Main Results:

• Lewis rats showed vigorous proliferation to V beta 8.2 (39-59) and other TCR peptides, but not to V beta 8.2 (18-38) or V beta 8.3 (62-76).
• Rat V beta 8.2 (39-59) was more immunogenic than its mouse counterpart, with moderate cross-reactivity.
• Genetic background influenced rat responses to V beta 8.2 (39-59) and V beta 14 (39-59), with hybrids resembling high responders.
• Lymphocytes specific for V beta 8.2 (39-59) did not respond to T cells expressing the V beta 8.2 product, suggesting a cryptic determinant.

Conclusions:

• Peptide V beta 8.2 (39-59) appears to be a cryptic determinant of the V beta 8.2 protein.
• Lymphocytes proliferating against V beta 8.2 (39-59) may not be the cause of EAE inhibition observed after vaccination.
• Immune responses to TCR peptides are complex and influenced by genetic factors and peptide structure.