B-CELL MITOGENIC ACTIVITY OF HOUSE-DUST MITE, DERMATOPHAGOIDES-FARINAE, ANTIGENS

The effect of mite antigens on murine and human lymphocytes was studie d in vitro. Antigens prepared from Dermatophagoides farinae feces and bodies stimulated normal murine spleen cells to proliferate in a dose- dependent manner. The responder cells are B cells, because the respons e was reduced by the treatment of spleen cells with anti-immunoglobuli n antibody and complement, but not with anti-Thy 1 antibody and comple ment. Furthermore, nylon column-purified T cells did not respond. The stimulation of B cells with mite antigens was not due to the contamina tion of lipopolysaccharide, a representative B cell mitogen, because C 3H/HeJ spleen cells which are low responders to lipopolysaccharide cou ld respond to mite antigens. These antigens induced not only prolifera tive response of murine B cells, but also immunoglobulin production. B y gel-filtration column chromatography, the active fractions were elut ed around the molecular weight of 150-155 kDa. Furthermore, mite antig ens also stimulated human B cells to proliferate and to produce immuno globulin. All these results suggest that mite antigens are a potent B cell mitogen and this activity might concern the induction of allergic reaction.