Effects of immunization with sperm specific lactate dehydrogenase with & without muramyl dipeptide as adjuvant

The effect of sperm specific lactate dehydrogenase-C4 (LDH-C4) alone or with muramyl dipeptide (MDP) and Freund's complete adjuvant (FCA) on immune responses and breeding capacity have been studied in isogeneic C57 BI/Ks (H-2d) mice. Results per se suggested that LDH-C4 generates isoantibodies even in absence of adjuvant. Though MDP could be substituted for FCA as adjuvant, amplification by MDP of the antibody levels is reduced to half that obtained with FCA. LDH-B4 from kidney did not produce any antibody response under similar conditions. Systemic immunization with LDH-C4 did not reduce the overall pregnancy rate but reduced the frequency of embryo resorption and increased litter size significantly. However, mothers with foetal non-resorption had in general, lower antibody titres than the mothers showing foetal resorptions. The popliteal lymph node (PLN) assay for local graft versus host (LGVH) reaction revealed that the maternal lymphocyte cell competence was depressed by the sperm specific isozyme during gestation; depression in stimulation index was associated with the low antibody titre group. MDP, like LDH-C4 alone did not modify LGVH reaction significantly although it exerted a similar effect as LDH-C4 in embryo protection.