The proliferative responses of cow stripping milk and blood lymphocytes to pokeweed mitogen and ginseng in vitro.

Milk samples were collected directly after the morning milking (stripping milk) from eight cows of the Swedish Red and White breed, during the period of mid-lactation. The milk cells (29 +/- 11 x 10(6)) were obtained after centrifugation and by passing the cell pellet through a cotton column. They consisted of 36 +/- 9% lymphocytes, 14 +/- 2% macrophages and 50 +/- 10% polymorphonuclear leukocytes. The autologous peripheral blood lymphocytes were separated by means of a Ficoll-gradient. The lymphocytes from the blood and milk were subjected to the lymphocyte stimulation test (LST). The stimulation indices (SI) demonstrated that pokeweed mitogen (PWM) induced a greater degree of proliferation in the autologous peripheral blood lymphocytes than it did in the stripping milk lymphocytes (39 +/- 8 vs 5 +/- 1, respectively, P < 0.01). Ginseng (GS), the root of Panax ginseng CA Meyer, has been used in China for thousands of years to enhance the body's resistance to many diseases. In the present study, a dry ginseng extract was investigated to evaluate its immunomodulating effects in vitro on the peripheral blood and stripping milk lymphocytes. The response was significantly augmented (approximately 20%) in the peripheral blood lymphocytes incubated with GS extract in combination with PWM, as compared with the cells incubated with PWM alone. Increased responses were also detected with the lymphocytes from stripping milk incubated with GS+PWM, but to a much lesser extent (approximately 9%) compared with the autologous peripheral blood lymphocytes.