APCS and tuberculosis: However, the physiological relevance of these observations is unclear, and although in vitro phenotypes associated with hSAP suggest it may protect against a variety of pathogens, including tuberculosis, malaria, or influenza A [22,25–27], other authors have shown that in mice SAP actually aids the virulence of S. pyogenes and E. coli, possibly by preventing classical pathway–mediated complement activity and phagocytosis [29,30].