MODULATION AND RECOVERY OF IMMUNE-RESPONSE OF BALB C MICE TO SHIGELLA-DYSENTERIAE ANTIGENS AFTER CYCLOPHOSPHAMIDE TREATMENT/

We have analysed the suppressive effect of cyclophosphamide, when give n in vivo, on the antibody response of BALB/c mice against Shigella dy senteriae antigens using ELISA and immunoblot. Out of various protocol s tried, it was found that co-injection of cyclophosphamide at 150 mg/ kg bodyweight, i.p., at the time of antigen administration and then af ter a lapse of 24 h during both primary and secondary immunizations, w as the most effective in suppressing antibody response of mice. Analys is of sera by ELISA demonstrated the presence of some antibodies to S. dysenteriae antigens after secondary immunization, but immunoblot ana lysis using the same sera revealed complete suppression of antibody re sponse. Animals whose antibody response was almost completely suppress ed after two immunizations with co-injection of cyclophosphamide, when immunized again after the lapse of 14 days from the date of secondary immunization with Shigella antigens but without administration of cyc lophosphamide, partially recovered their ability to respond to the sam e antigens. This protocol can now be used in mice to analyse the hiera rchy of immunogenic epitopes present in a complex mixture of antigens.