Erythrocyte rosette formation of equine peripheral blood lymphocytes.

Erythrocyte rosette (ER) formation of equine peripheral blood lymphocytes (PBL) was characterized. Guinea pig and, to a lesser extent, human erythrocytes formed ER; cat, cow, dog, hamster, mouse, rat, and sheep erythrocytes showed negligible rosetting properties. Conditions of the assay were varied to determine which procedure allowed the largest percentage of rosette formation. The PBL from 20 normal horses were then assayed, averaging 38 +/- 2% ER. To characterize the erythrocyte receptor as being on T or B cells, equine thymocytes from 6 foals were assayed; the thymocytes formed an average of 66 +/- 5% ER. Mixed ER and erythrocyte-antibody-complement rosette assays showed no PBL which bound both ER and erythrocyte-antibody-complement rosettes. The PBL which was stimulated with phytohemagglutinin formed more rosettes (69 +/- 2%) than nonstimulated, control PBL (42 +/- 3%).