Production of a monoclonal antibody using lymphocytes from Pneumocystis infected mice.

A colony of BALB/c mice maintained in a protected area of our laboratory was not infected with Pneumocystis carinii. During corticosteroid treatment, animals became infected by exposure to infected mice. After four months of corticosteroid treatment, BALB/c mice developed severe pneumocystosis. Stopping of treatment was associated with: (i) high mortality of mice, (ii) decreased lung parasite level and (iii) appearance of anti-P. carinii antibodies in survivors. A monoclonal antibody (MAb) 4F2 was obtained by immortalisation of spleen lymphocytes of a female BALB/c mouse 3 months after the cessation of corticosteroid treatment. The MAb 4F2 recognized a 210-220 kDa mouse P. carinii antigen, but did not react with rat-, rabbit- or human-derived P. carinii. This MAb reacted with all stages of mouse P. carinii.