The effects of antilymphocytic serum (ALS) on Trypanosoma lewisi infection.

Abstract

SYNOPSIS. ALS was produced in rabbits immunized with cells collected from spleens and mesenteric lymph nodes of normal female Holtzman rats. The ALS was pooled and leucoagglutination tests were performed to determine the ability of the antiserum to agglutinate rat white blood cells in vitro. ALS employed in the study had a titer of 1 :512.Treatment of rats with ALS prior to and during Trypanosoma lewisi infection resulted in suppression of the immune response. Ablastin production was inhibited. The numbers of dividing forms of the parasites were higher in ALS‐treated rats during the course of infection than in controls injected with saline or normal rabbit serum. ALS‐treated rats continued to have a higher parasitemia than the controls and died 5–12 days post‐infection. Hematocrit readings were lower in the ALS‐treated rats infected with T. lewisi than in rats infected with T. lewisi or normal animals treated with ALS.