MANIPULATION OF THE HELPER T-CELL RESPONSE TO INFLUENCE ANTIGENIC-COMPETITION OCCURRING WITH A MULTIVALENT VACCINE

The reduction in antibody observed following inoculation with multiple heterologous Dichelobacter nodosus pill antigens is thought to be due to competition between antigen-specific B cells for a limited amount of T cell help. We demonstrate here that this competition is not furth er influenced by the expansion of cross-reactive antibody secreting ce lls at the expense of serogroup specific antibody secreting cells. The T cell determinants of pill recognized by sheep and BALB/c mice have been defined using 15 residue peptides. These T cell determinants incl ude cross-reactive determinants in the conserved amino terminal region of the antigen. Here we investigate the effect of expanding the pill- specific T cell population by griming with pill derived T cell determi nants. It was not possible to increase the antibody elicited in respon se to the multivalent vaccine by priming mice with either a synthetic peptide spanning a T cell determinant or with reduced and alkylated or heterologous serogroups of pili 4 weeks before inoculation with the m ultivalent vaccine. A strategy designed to increase the T cell populat ion by inoculating animals with pill covalently coupled to an extrinsi c T cell determinant was pursued.