EN
The effect of lysozyme dimer (20 μg/kg) administered i.p. once or four times to mice immunized with sheep red blood cells (SRBC) on the secondary humoral response was studied with respect to the time of exposure to the drug in relation to priming and challenge. It has been found that lysozyme dimer potentiates secondary humoral response to SRBC resulting in an increased number of splenocytes producing hemolytic anti-SRBC antibodies (PFC) and anti-SRBC hemagglutinin titers (total and 2-mercaptoethanol resistant) when the drug is administered after the challenge. Both a single dose and four doses of lysozyme dimer administered after priming and challenge prolong its potentiating effect on anti-SRBC hemagglutinin titers as compared to the mice treated with lysozyme dimer only after challenge. A single dose of lysozyme dimer (20 μg/kg) administered only after priming does not affect secondary humoral response of SRBC-immunized mice. However, four doses of lysozyme dimer administered only after priming enhance the secondary humoral response to this antigen after challenge.