Capping of complement receptors on human neutrophils induced by group A streptococcal cell walls

J Immunol. 1983 Apr;130(4):1674-7.


Peptidoglycan-polysaccharide polymers derived from group A streptococcal cell walls (PG-PS) were opsonized with either purified C3 or normal human serum and were used as a probe to investigate the mobility of CR1 and CR3, the C3b and iC3b receptors, respectively, on human neutrophils. Incubation of monolayers or cell suspensions of neutrophils with PG-PS opsonized with C3b or serum resulted in capping of PG-PS, as detected by fluorescein-labeled antibody to PS. No binding of PG-PS to neutrophils was observed with heat-inactivated serum. By 30 min the cell walls were internalized and observed in one to three vacuoles. Capping was totally inhibited when PG-PS opsonized with C3b or serum was preincubated with Fab'-anti-C3b. Similar inhibition was observed when C3b-opsonized PG-PS was incubated with neutrophils that were preincubated with anti-CR1 or fluid-phase C3b; only partial inhibition of neutrophil capping was observed by using serum-opsonized PG-PS. Because anti-CR1 blocks only the C3b receptor, the cap formation observed with serum-opsonized PG-PS is probably due to CR3. These results suggest that both CR1 and CR3 on neutrophils cap after stimulation by group A streptococcal cell wall fragments.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Binding, Competitive
  • Complement C3b / metabolism
  • Complement C3b Inactivator Proteins / metabolism
  • Humans
  • Immunologic Capping*
  • Neutrophils / metabolism*
  • Polysaccharides, Bacterial / analysis
  • Polysaccharides, Bacterial / blood
  • Polysaccharides, Bacterial / pharmacology*
  • Rabbits
  • Receptors, Complement / analysis*


  • Complement C3b Inactivator Proteins
  • Polysaccharides, Bacterial
  • Receptors, Complement
  • streptococcal polysaccharide group A
  • Complement C3b