Inhibition of lymphocyte trapping by cell-free ascitic fluids cultivated in syngeneic mice.

Several cellfree ascitic fluids were tested for their influence on the trapping of lymphocytes in peripheral lymph nodes after subcutaneous antigen administration. Fluid from three ascitic tumors cultivated in syngeneic mice diminished the trapping response significantly. Fluid from one of these ascitic tumors cultivated in allogeneic mice showed no inhibition of trapping. Syngeneic normal mouse serum did not significantly affect the trapping phenomenon. It was concluded that syngeneic ascitic fluids contain a substance capable of inhibiting lymphocyte trapping.