Flow cytometric analysis of goat milk lymphocytes: subpopulations and adhesion molecule expression

Cytometric analysis of cells in milk from healthy goats was achieved after elimination of interfering signals from debris and dead cells by irreversible staining with ethidium monoazide. Some 61% of milk lymphocytes are CD8+ T cells, 17% are CD4+ and about 20% of these express class II antigens: less than 4% are B cells. Compared with blood, the CD4/CD8 ratio was inverted and fewer lymphocytes expressed CD4SR or L-selectin. Monoclonal antibodies to ovine integrins recognised the caprine alpha 4 chain on most lymphocytes from milk or blood, while beta 1 was more frequent on milk cells.