CHARACTERIZATION OF FELINE T-CELLS AND B-CELLS

Feline peripheral-blood lymphocyte populations (n = 22) were examined for the following markers: rosette formation with guinea pig erythrocytes (GPE-T cells), rosette formation with human RBC (HRBC-T cells), rosette formation with sheep RBC, mixed rosette formation with GPE-T cells and HRBC-T cells (total T cells), erythrocyte antibody-complement rosettes, and surface immunoglobulin. An average of 28% .+-. 7% (range, 16% to 39%) of the feline lymphocytes formed rosettes with GPE-T cells, and 27% .+-. 7% (range, 11% to 36%), with BRBC-T cells. An average of 57% .+-. 9% (range, 33% to 75%) of the lymphocytes formed mixed rosettes. The erythrocyte antibody-complement rosette-forming cells and surface immunoglobulin-bearing cells were found in peripheral blood lymphocytes (10% .+-. 6% and 24% .+-. 8%, respectively). The murine monoclonal antibodies OKT 11 and HuLy-m1, specific for a framework determinant of human E-rosette receptor antigens, cross-reacted with feline cell membrane molecules recognizing a bimolecular complex (45,000 to 50,000 daltons) similar to that described in persons. We investigated the distribution of these E-rosette receptor-like antigens on feline lymphocytes. By complement-mediated lymphocytotoxicity, about 30% of the feline lymphocytes expressed the antigens. When lymphocytes were treated with HuLy-m1 antibody, spontaneous rosette formation with HRBC-T cells was significantly inhibited.