T mu- and T gamma-cell subsets in normal and leukemic cattle.

T-cell subsets in the peripheral blood and lymphoid organs of normal and chronic lymphocytic leukemia (CLL) cattle were studied. Purified T lymphocytes were examined for the numbers of cells with the receptors for IgM (T mu) and IgG (T gamma). The expression of surface receptors on T mu- and T gamma-cell subsets was determined according to their capacity to bind different numbers of erythrocyte antibody complexes EAM or EAG. During the various times of preincubation of T cells at 37 degrees C, an increased release of receptors on the surface of T mu and partly T gamma cells was observed. For the optimal detection of bovine T mu cells, preincubation at 4 degrees C fro 24 h was necessary. The number of T gamma cells in the peripheral blood (P less than 0.001) and spleen (P less than 0.001) of CLL cattle was higher in comparison with controls. A considerably reduced number of T mu cells in the peripheral blood (P less than 0.001) and lymph nodes (P less than 0.02) of CLL cattle was observed. With the exception of thymus, T gamma cells from the lymphoid organs of CLL cattle had a higher expression of receptors than normal T gamma cells.