Attempts to infect experimentally immunosuppressed iris monkeys (Macaca iris) with Brugia malayi

Iris monkeys resistant to repeated infections with B. malayi were subjected to immunosuppression by treatment with cortisone. Degree of immunosuppression was measured by: (a) blood counts, (b) lymphocyte transformation to mitogens and (c) immunofluorescent antibody to microfilarial antigens. Attempts were made to infect such immunosuppressed animals with B. malayi. No microfilariae were detected in the blood of any of the Iris monkeys during the 6 months of study. There was a sharp drop in the percentages of lymphocytes, but a rise in neutrophil counts during the first week of cortisone administration. Treatment with cortisone did not alter the antibody titres. The significance of this line of approach in the understanding of filarial resistance is discussed.