COMPARISON OF THE REQUIREMENT OF PORCINE PERIPHERAL-BLOOD MONOCYTES AND INTESTINAL LAMINA PROPRIA MACROPHAGES AS ACCESSORY CELLS IN PRIMARYALLOGENEIC MIXED LEUKOCYTE RESPONSES AND OXIDATIVE MITOGENESIS

Differences and/or similarities of the accessory cell activity of circ ulating peripheral blood monocytes (PBM) and intestinal lamina propria macrophages (LPM) in the pig have never been evaluated. Therefore thi s study was designed to compare the accessory cell activity of these c ells in the induction of primary allogeneic mixed leukocyte responses (MLR) and polyclonal mitogenesis. Splenic adherent cells (SPAC) were u sed as control accessory cells. It was observed that PBM, LPM and SPAC induced significant T cell proliferation in response to allo-antigens . Significantly higher responses were elicited by SPAC, followed by PB M whereas, LPM induced low responses when cultures were established a T cell: accessory cell ratio of 1:1. PBM was the only accessory cell w hich induced significant responses at a cell ratio of 10:1. Whereas LP M and SPAC were able to induce significant oxidative mitogenesis, PBM were poor stimulators of this response. The observed difference betwee n PBM, SPAC and LPM is attributed partly to differences in number of m ajor histocompatibility complex (MHC) class II positive cells and the intensity of expression of the glycoproteins.