Immunoglobulins inhibit adherence and internalization of Streptococcus pyogenes to human pharyngeal cells.
Purified human sIgA against group A streptococci inhibited streptococcal adherence to pharyngeal cells whereas rabbit serum raised against the whole M+ strain did not. Of note, inhibition of adherence by sIgA occurred despite a much lower immunreactivity against the M6 protein as compared to the hyperimmune serum against the whole M+ strain. The M protein does probably not mediate the adherence of group A streptococci to respiratory cells, as shown by previous studies. However, since the isogenic M- derivative was less invasive to human pharyngeal cells than the M+ strain, our invasion experiments suggest that the M protein may play a role in internalization of group A streptococci into eukaryotic cells. More importantly, internalization and not adherence could be blocked by rabbit serum immunized with recombinant M6 protein.
Fluckiger
U
U
Rockefeller University, New York, New York 10021, USA.
Fischetti
V A
VA
D000818:Animals; D000907:Antibodies, Bacterial / Q000494:pharmacology; D000942:Antigens, Bacterial; D001422:Bacterial Adhesion / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000276:immunology; D002352:Carrier Proteins; D002460:Cell Line; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000494:pharmacology; D007136:Immunoglobulins / Q000494:pharmacology*; D010612:Pharyngitis / Q000209:etiology / Q000276:immunology / Q000382:microbiology; D010614:Pharynx / Q000276:immunology / Q000382:microbiology*; D011817:Rabbits; D012463:Saliva / Q000276:immunology; D013290:Streptococcal Infections / Q000209:etiology / Q000276:immunology / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000276:immunology* / Q000472:pathogenicity
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D007071:Immunoglobulin A, Secretory; D007136:Immunoglobulins; C014689:streptococcal M protein