engleski

Equine peripheral blood lymphocyte responses following immunization with tetanus toxoid and toxin

The main objective of the current study was to establish whether or not it is possible to detect the highly reactive horses suitable for tetanus hyperimmune serum production based on their in vitro cellular immunoresponsiveness to tetanus toxoid (TTd). Additionally, we have evaluated the priming effect of the immunization with TTd and tetanus toxin (TT) for horses by the assessment of their peripheral blood lymphocyte (PBL) in vitro. The proliferation of equine PBL was induced with either common mitogens (PHA or PWM) or specific antigens (TTd or TT) in lymphocyte stimulation test. Their effector functions were assessed by direct cytolysis (DC) and antibody-dependent cellular cytolysis (ADCC). For phenotyping of immune cells involved the flow cytometric analysis was used. About 50% (11 of 23) of unimmunized horses appeared to be nonresponders to TTd as their PBL responded poorly to stimulation with PHA or PWM. Responses of the cells from TTd/TT-treated horses to PHA (P<0.01) or PWM (P<0.05) was lower at Days 35 and 63 after the immunization, respectively, than of the control cells (at Day 0) from unimmunized animals. The effector cells from immunized horses exhibited a stronger cytolytic activity against autologous target lymphoblasts in either DC (6.6% or about 7 times) or ADCC (18.2% or about 9 times) than the control cells. This is probably due to more abundant CD4^+ and CD8^+ subsets in the peripheral blood (P<0.05) of TTd/TT-treated horses. However, the percentage of antigen presenting cells was lower (P<0.01) in these animals. Considering all, it seems likely that the lymphocyte stimulation test could be of practical value as a tool for selecting horses intended for the production of hyperimmune serum against tetanus.

Cellular immunity ; tetanus toxoid/toxin ; horse

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