Depression of B-lymphocyte levels in the peripheral blood of cows with mastitis.

The levels of B-lymphocytes in the peripheral blood of normal and mastitic cows were evaluated by fluorescent-antibody and erythrocyte-antibody-complement-rosetting techniques. Normal cows (N = 8) had 26.9 +/- 4.4% surface membrane immunoglobulin-positive lymphocytes, whereas mastitic cows (N = 6) had only 16.3 +/- 3.6% similar cells among lymphocyte preparations purified by the Ficoll-Paque density gradient separation and carbonyl iron phagocytosis methods. Studies on smiliar lymphocyte preparations by erythrocyte-antibody-complement-rosetting techniques showed that normal cows (N = 12) had 33.5 +/- 7.1% erythrocyte-antibody-complement-rosetting lymphocytes, whereas mastitic cows (N = 6) had 20.5 +/- 6.0% similar cells.