RECOGNITION OF PNEUMOCYSTIS-CARINII ANTIGENS BY LOCAL ANTIBODY-SECRETING CELLS FOLLOWING RESOLUTION OF PNEUMOCYSTIS-CARINII PNEUMONIA IN MICE

To examine the repertoire of Pneumocystis carinii antigens recognized by antibody-secreting B cells from tracheobronchial lymph nodes isolat ed immediately following recovery from P, carinii pneumonia, monoclona l antibodies (MAbs) were produced from these cells. In contrast to pre vious studies of systemic immunity, P, carinii gpA was not the immunod ominant antigen recognized by these B cells. Forty-nine (91%) of 54 P, carinii-specific hybridoma culture supernatants reacted with P, carin ii antigens other than gpA. Many of the resulting MAbs recognized a pr eviously uncharacterized antigen expressed on the surface of both cyst s and trophozoites. Western blotting using one of the cloned MAbs reve aled reactivity with a broad range of antigenic material, with the mos t intense reactivity in the 50- to 65-kDa region of the blot. The anti gens identified by these MAbs merit further investigation regarding pr otective immunity to P. carinii because they were recognized by B cell s in the context of recovery from I? carinii pneumonia.