LYMPHOCYTE TRANSFORMATION OF PERIPHERAL BLOOD LYMPHOCYTES AND PLAQUE FORMING CELLS OF THE SPLEEN AND THE MESENTERIC LYMPH NODE IN SUCKLING PIGLETS WITH AND WITHOUT IMMUNOPOTENTIATORS

Lymphocyte transformation with mitogen, phytohemagglitinin (PHA) and concanavalin A (conA) was tested in peripheral blood lymphocytes from suckling piglets aged 1,2,3,4 and 5 weeks old respectively. A study was also made to observe plaque forming cells with sheep red blood cells (SRBC) in the spleen and nucleated cells of the mesenteric lymph nodes (MLN) of piglets aged 2,3 and 4 weeks respectively. Reratively high levels of lymphocyte responses were seen in the 1 week-old piglets. Differences of stimulation indexes (SI) of lymphocyte responses of the piglets were not significant in the animals aged from 1 to 5 weeks. The effect of administration of peptidoglycan and chemical composites of cultural supernates derived from Streptomyces olivaceogriseus sp. nov (FR41565) on the lymphocyte responses was investigated. The value of SI among the piglets treated with and without peptidoglycan and FR41565 was not significant. On the other hand, the count of plaque forming cells (PFC) of the splenic and MLN's cells with SRBC in the piglets aged 2 to 4 weeks was low in spite of the SRBC injections, and the count of PFC of MLN was fewer than that of the spleen of any age. The count of PFC was the highest in the piglets treated with the rapid acting immunopotentiator (FR41565) at 2 weeks of age while the highest count was seen in the piglets administered the slow acting substance (peptidoglycan) at 4 weeks of age. These results indicated that differentiation of B lymphocyte in suckling age piglets seems to be restrained by a certain suppressive activity which leads to poor production of immunoglobulin