Generation by Bacterial Proteinases of Leukotactic Factors from Human Serum, and Human C3 and C5

Proteinases derived from Serratia marcescens and group A, β-hemolytic Streptococcus are each able to generate, by cleavage, leukotactic fragments from human C3 and C5. In whole human serum, the Serratia enzyme produces a C3-related leukotactic factor, while the streptococcal proteinase produces a C5-related factor. The finding that proteinases derived from bacteria are able to generate complement-dependent leukotactic factors suggests that this may be one mechanism by which bacteria incite and maintain inflammatory reactions in tissues.