The effect of protease inhibitors on the immune response in mice

The effect of protease inhibitors on the immune response in mice was investigated. Soybean inhibitor, aprotinin, alpha 1-antitrypsin and ovomucoid (1 mg) diminished significantly the direct plaque forming cell response per spleen 3 days after immunization with 10(8) sheep erythrocytes (SRBC), when given at the same time as the antigen. With alpha 1-antitrypsin, the effect was not significant 4 days after immunization. With soybean inhibitor, no significant suppressive effect was seen, when the inhibitor was given either 24 hours before or after the antigen. Both aprotinin and ovomucoid diminished a secondary response to SRBC, limited to the indirect plaque forming cells. Soybean inhibitor had an equivocal effect on the secondary response. A suppressive effect of soybean inhibitor, but not ovomucoid was seen using KLH-FITC or LPS-FITC as antigens. Neither soybean inhibitor nor aprotinin had an effect on the induction of delayed-type skin reactivity to oxazolone or FITC.