EXPRESSION OF THE ARP PROTEIN, A MEMBER OF THE M-PROTEIN FAMILY, IS NOT SUFFICIENT TO INHIBIT PHAGOCYTOSIS OF STREPTOCOCCUS-PYOGENES

Many Streptococcus pyogenes immunoglobulin-binding proteins have struc tural similarities to the antiphagocytic M protein, including the well -known C repeats. One of these molecules is the immunoglobulin A-bindi ng protein Arp, which is expressed by a serotype 4 strain for which no antiphagocytic M protein has yet been described. We expressed Arp4 in an S. pyogenes strain from which the structural gene for the M protei n has been deleted and found that Arp4 is not sufficient to inhibit ph agocytosis.