AFFINITY OF TETANUS VACCINE IN THE LATE PRIMARY IMMUNE RESPONSE AFTER THE END OF THE GERMINAL CENTER REACTION

The immune response of experimental animals against tetanus toxoid (TT) vaccine was developed within 14 days post vaccination. Recorded data revealed that antibody (Ab) level was time related, and the intraperitoneal (IP) administration of vaccine showed a higher Ab level in a significant way than subcutaneous (SC) one. Avidity index showed higher significant difference in case of IP administration than SC one. The avidity index post intravenous administration of anti-CD154 (MR1) monoclonal Ab was detected using ELISA technique and germinal centers (GCs) were detected using immunofluorescence assay (IFA). Histopathological examination revealed that the peaking of GCs was on the 10th day post vaccination and an obvious deterioration was recorded on day 33 post vaccination. It was found that the avidity index of serum Ab in MR1 injected group was significantly lower than non MR1 injected group at day 69, suggesting that GCs generate the precursors of high affinity BM AFCs. This finding suggests that memory B cells and long-lived antibody secreting plasma cells may represent independently regulated cell populations and may play different roles in the maintenance of protective immunity.