Effective and ineffective antilymphocyte sera correlation of in vitro tests with potency of early antisera

Effect of anti-thymocyte serum on the eosinophil and lysophospholipase responses in mice infected with Trichinella spiralis

Anti-thymocyte serum (ATS) was administered to CD-1 mice infected with 100 Trichinella spiralis larvae and its effects on intestinal lysophospholipase (EC 3.1.1.5) activity, peripheral blood lymphocytes and bone marrow, peripheral blood and intestinal eosinophilia were assayed in the same experimental animal. The ATS caused a significant suppression of both the tissue lysophospholipase response and eosinophilia, in all three compartments, when compared to the values found in infected mice that were either treated with normal rabbit serum (NRS) or untreated. The suppressed eosinophil response and reduced lysophospholipase activity demonstrated a close temporal relation throughout the experiment. These findings support the hypothesis that helminth parasite-induced eosinophilia is the cause of increased lysophospholipase activity present in parasitized tissue and that the responses are thymus cell dependent.

Effect of antithymocyte serum on experimental toxoplasmosis in mice

The effect of antithymocyte serum (ATS) on mice infected with high-virulent or low-virulent strains of Toxoplasma gondii was studied. Treatment with ATS reduced the survival time of mice infected with high-virulent Toxoplasma and aggravated the disease; treatment prolonged parasitemia in animals infected with low-virulent Toxoplasma. Although ATS adversely affected the humoral antibody response, its main effect on toxoplasmosis was probably due to depression of cell-mediated immunity. ATS appeared to be able to activate chronic Toxoplasma infection, but this effect was much less pronounced than that on acquisition of immunity. The results suggest that Toxoplasma infection should be routinely looked for in patients treated with antilymphocyte serum.