Immunity in Group A Streptococcal Infections I. Non-Specific Protective Effect in Repeated Pulmonary Infections. ∗

Abstract

Summary

1. It was noted that after pneumonic infection with group A streptococci and treatment with procaine penicillin, rats exhibited a degree of protection against a second pulmonary infection, induced in a different lobe with a strain of different type, not demonstrable in previously uninfected animals. This non-specific protective effect was of limited degree and could be obscured when the challenging infections were especially virulent. 2. Evidence is presented which indicates that the protective effect noted is not due (a) to the presence of phagocytes and/or structurl alterations prior to the induction of the second infection, or (b) to the persistence of inhibitory levels of penicillin in the lung tissue per se. 3. The implications of these observations are discussed.