T and B cell human responses to European bat lyssavirus after post-exposure rabies vaccination

T and B cell human responses to European bat lyssavirus (EBL1) induced by post-exposure rabies vaccination (PM virus vaccine) were evaluated by measuring plasmatic titres of EBL1-specific neutralizing antibodies; specific EBL1-binding antibodies; and proliferation indices of peripheral blood lymphocytes stimulated in vitro with EBL1. These parameters for vaccination efficacy were compared with those obtained with vaccine-related viruses (CVS and ERA) and with a non-vaccine-related virus. Mokola virus, the last implicated in vaccination failures. Twenty-two patients exposed to rabies risk who received a reduced rabies post-exposure vaccination were involved in the study. On day 21, vaccine induced CVS-specific neutralizing antibodies in all patients; but EBL1-specific neutralizing antibodies were induced in only 73% of patients. No vaccine had Mokola-specific neutralizing antibodies. Patients having EBL1-specific neutralizing antibodies were usually those in whom vaccination induced high titres of CVS-specific neutralizing antibodies. On day 21, peripheral blood lymphocytes of 86% of patients could be restimulated in vitro with vaccine, 43% with EBL1 and 45% with Mokola. Patients exhibiting a high vaccine-specific proliferation response more likely developed an EBL1- or a Mokola-specific proliferative response. No correlation was found between T and B cell responses. Rabies vaccination induced neither T nor B cell EBL1-specific responses in 22% of patients.