SELF GAMMA-2A(B) PROTEIN IS PRESENTED IN-VIVO BY GAMMA-2A(B) B-CELLS BUT NOT BY DENDRITIC CELLS

We have previously shown that IgG2a(b) Ig does not induce tolerance in MHC class II restricted CD4 T cells in a TCR transgenic model and tha t anti-IgC2a(b) transgenic T cells specific for peptide 435-451 are in deed present in the periphery where they interact with gamma 2a(b)-pos itive B cells, We also observed that because T cell tolerance depends on the presentation of self peptides, it was probable that IgG2a(b) wa s not easily processed and presented in vivo, In this study, we have i nvestigated the presentation of naturally processed gamma 2a(b) (435-4 51) determinants to specific T cells. Dendritic cells, macrophages, an d B cells were purified from the spleens of Igh-1b mice, These cells w ere then functionally tested for the presence of specific peptide-MHC complexes, The results showed that, in vivo, gamma 2a(b)-producing B c ells, but not dendritic cells, are the only APCs able to present this self peptide, This indicates that recognition of the IgG2a(b)-self pep tide is exclusively mediated by T-B cell interaction.