In vitro activation and detection of antibody-secreting cells from Trypanosoma congolense-infected cattle.

B cells from the peripheral blood and spleen of Trypanosoma congolense-infected cattle and from the peripheral blood of an uninfected cohort were analysed for ability to secrete antibody and for expression of surface antigens before and after in vitro culture with interleukin-2, lipopolysaccharide and pokeweed mitogen. Antibody-secreting cells (ASC) were only detected in lymphocytes from peripheral blood after in vitro stimulation. The frequency of ASC was greater in cultures of lymphocytes from infected cattle than from the uninfected cohort. The frequency of ASC was positively correlated with the number of B cells expressing the transferring receptor but not with the expression of the CD5 antigen.