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 CD4CD8 ratio was inverted and fewer lymphocytes expressed CD45R or L-selectin. Monoclonal antibodies to ovine integrins recognised the caprine α4 chain on most lymphocytes from milk or blood, while β1 was more frequent on milk cells.