Related Experiment Videos
Effect of group B streptococcal type-specific antigen on polymorphonuclear leukocyte function and polymorphonuclear
Pediatric Research
|June 1, 1987
Summary
Group B streptococcal (GBS) type III antigen inhibits polymorphonuclear leukocyte (PMN) movement and adherence to endothelial cells, potentially hindering the immune response in neonatal pneumonia.
Area of Science:
- Immunology
- Neonatal Medicine
- Microbiology
Background:
- Neonatal group B streptococcal (GBS) pneumonia is a severe, often fatal, condition.
- Autopsies reveal findings similar to hyaline membrane disease, with bacteria in alveoli but few polymorphonuclear leukocytes (PMNs) at invasion sites.
- Aggregated PMNs are observed in pulmonary capillaries, suggesting impaired migration.
Purpose of the Study:
- To investigate the impact of GBS type III antigen on PMN chemotaxis.
- To examine the effect of GBS type III antigen on PMN-endothelial cell interactions.
Main Methods:
- Human PMNs were isolated and pretreated with varying concentrations of GBS type III antigen.
- Chemotactic responses to formyl-methionyl-leucyl-phenylalanine, zymosan-activated serum, platelet-activating factor, and leukotriene B4 were assessed.
- PMN adherence to endothelial cells was measured with and without serum containing GBS antibodies.
Main Results:
- GBS type III antigen significantly inhibited chemotaxis mediated by formyl-methionyl-leucyl-phenylalanine, zymosan-activated serum, and platelet-activating factor in a dose-dependent manner.
- Leukotriene B4-mediated chemotaxis was not significantly affected.
- GBS antigen inhibited PMN adherence to endothelial cells without serum but enhanced it in serum deficient in GBS antibody.
Conclusions:
- GBS type III antigen alone may impede PMN infiltration into the alveoli during infection.
- The antigen's effect on PMN adherence is modulated by the presence and antibody content of serum.
- These findings shed light on the pathogenesis of GBS pneumonia and potential immune evasion strategies.