Toll-Like Receptor 2 Deficiency Delays Pneumococcal Phagocytosis and Impairs Oxidative Killing by Granulocytes

Phagocytosis and killing of Streptococcus pneumoniae was compared in blood-derived wild-type (WT) and Toll-like receptor 2 (TLR2)-deficient (TLR2−/−) polymorphonuclear leukocytes (PMN). Phagocytosis of green fluorescent protein-transformed pneumococci was delayed in TLR2−/− PMN. These cells exhibited also a lower oxidative bactericidal activity against S. pneumoniae than WT PMN, suggesting that TLR2 modulates bacterial clearance in PMN.