[Kinetics of lymphocyte sub-populations and plasma cells in the mammary gland of primiparous sows in relation to gestation and lactation].

Qualitative and quantitative changes in pig lymphocyte sub-populations (T, B, L and nulls) were studied in the mammary gland of primiparous sows, as well as the appearance and development of plasma cells in relation to the 3 phases of mammary development: gestational, colostral and lacteal phases. Results showed: 1) An early colonisation of mammary epithelium from the beginning of the gestation phase by the three T, B and L lymphocyte subpopulations; 2) The presence of activated T lymphocytes, especially during the colostral phase; 3) The appearance of plasma cells during the colostral phase and their increase during the lacteal phase; 4) Not only the T, B and L lymphocyte subpopulations increased during the lactation but there was also a special increase in null lymphocyte subpopulation. These results give new data which are particularly important in allowing us to envisage immunization schemes for the pregnant sows, with the aim of enhancing local mammary or lactogenic immunity by transfer of antibodies and lymphocytes to the newborns.