INFECTION WITH NIPPOSTRONGYLUS-BRASILIENSIS INDUCES INVASION OF MAST-CELL PRECURSORS FROM PERIPHERAL-BLOOD TO SMALL-INTESTINE

Precursors of mast cells were defined as cells that formed mast-cell c olonies in methylcellulose culture (CPU-mast). Mononuclear cells (MNC) were obtained from the bone marrow, peripheral blood, and small intes tine of Ws/Ws rats with a small deletion at the tyrosine kinase domain of c-kit and of control normal (+/+) rats. In the culture containing concanavalin A-stimulated spleen cell conditioned medium (ConA-SCM) al one, the numbers of mast-cell colonies produced by Ws/Ws MNC were comp arable with those of +/+ MNC. In the culture containing both ConA-SCM and stem cell factor (a ligand of c-kit), however, the numbers of mast -cell colonies produced by +/+ blood MNC were 107 times as great as th at of Ws/Ws blood MNC. Using this culture condition, we investigated c hanges in concentration of CFU-mast in the marrow, blood, and intestin e of +/+ rats after infection with Nippostrongylos brasiliensis (NB), which induced marked mast-cell accumulation in the small intestine. Th e concentration of CFU mast in blood dropped to 21% of preinfection le vels 1 week after the NE infection. In contrast, a sevenfold increase of CFU-mast occurred in the small intestine. The proportion of CFU-mas t in S phase of the cell cycle remained at low levels in the marrow an d blood after NE infection, but it increased significantly in the smal l intestine. The present result suggests that NE infection induces the invasion of CPU-mast into the intestine from blood and their subseque nt proliferation in the tissue site. (C) 1995 by The American Society of Hematology.