Streptococcal M protein

Virulence factor of Group A beta-hemolytic streptococcus. Over 80 different types. M proteins may allow the organism to escape the host defenses by: 1) evading antibody recognition 2) inhibiting phagocytosis M types 1 & 3 produce streptococcal pyrogenic exotoxin A, B &/or C. M types 1, 3 & 18 have increased virulence.

References

Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998