IMMUNE RECEPTOR REPERTOIRE FOR INFLUENZA HEMAGGLUTININ

An extensive analysis was made of receptor specificity and gene usage in the neutralising antibody (mAb) and Class II-restricted T cell resp onses to influenza haemagglutinin (HA) following natural infection of MHC (H-2(k) or H-2(d)) congenic mice with X31 virus (H3N2 subtype). De spite the diversity of available antigenic sites on the HA1 subunit, t here was striking immunodominance in the mAb response as deduced by se quencing the HA genes of escape mutants and the corresponding antibody H and L chain gene rearrangements. Similarly, Class II restricted T c ell responses of individual donors focused on a single antigenic site, or immunodominant peptide; and PCR sequence analysis of T cell recept or (alpha beta) gene usage indicated that T cell memory was derived fr om a single progenitor cell. Focusing of the immune repertoire to limi ted regions of the HA molecule during a primary viral infection may be a significant factor in immune pressure for antigenic variation.