The efficacy of chemical bursectomy in chickens with congenital leukosis-virus infection.

Since treatment with Freund's complete adjuvant in chickens with congenital avian leukosisvirus infection results in severe hypergammaglobulinaemia, it was of interest to determine how various means of chemical bursectomy affected such animals. Testosterone injected during the embryonic period or cyclophosphamide administered neonatally were, alone, relatively ineffectual in suppressing the response to influenza virus or production of natural rabbit haemagglutinins, nor did these treatments reliably depress IgG or IgM levels. However, the combination of both testosterone and cyclophosphamide completely suppressed antibody responses to the antigens and resulted in animals with serum immunoglobulin levels 10-(4)-10-(5) that of untreated hypergammaglobulinaemic controls.