2 PHENOTYPICALLY DISTINCT B-LYMPHOCYTES (IGM(HIGH)IGD(LOW) AND IGM(LOW)IGD(HIGH)) IN CHRONIC GASTRIC-ULCER IN THE RAT

We determined the kinetics and phenotypes of infiltrating B cells in g astric ulcer in the rat induced by gastric injection of acetic acid (d ay 0). Few B cells were found in the lesion in the early stages of ulc eration. On day 40, two kinds of B cells with phenotypes of IgM(high)I gD(low)OX33 (CD45)(+)OX19 (CD5)(-) and IgM(low)IgD(high)OX33(CD45)(+)O X19(CD5)(-) were scattered in the granulation tissue of open ulcers, b ut not in the healed scar tissue. On day 180, those two kinds of B cel ls formed primary follicles in the granulation tissue of open ulcers, but were absent from the healed scar tissue. The IgM(high)IgD(low)OX33 (CD45)(+)OX19(CD5)(-) B cell was considered to be identical to the mar ginal zone B cell of rat spleen. This phenotype of B cell might be ass ociated with inflammatory process in chronic gastric ulcer.