Identification of canine lymphocyte populations by immunofluorescence surface marker analysis

A T-cell-specific rabbit anti-dog thymocyte antiserum was prepared and used in an indirect fluorescent antibody technique to identify T lymphocytes. The antiserum was rendered specific by absorptions with normal dog red blood cells, lyophilized serum, and bone marrow cells. By the indirect immunofluorescence assay, 73.6 +/- 1.2 (SEM)% of the peripheral blood lymphocytes were identified as T lymphocytes. By direct immunofluorescence assay of surface membrane immunoglobulin-positive lymphocytes, 18.2 +/- 0.8% of the peripheral blood lymphocytes were identified as B lymphocytes. The two assays used in conjunction can thus identify over 90% of the peripheral blood lymphocytes as either T or B lymphocytes, with the remaining 8.2 +/- 1.0% as null cells.