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Ovine opsonins for Staphylococcus aureus cell wall and pseudocapsule
1CSIRO, Division of Animal Health, Armidale, New South Wales, Australia.
Research in Veterinary Science
|January 1, 1989
Summary
Sheep antibodies against Staphylococcus aureus were studied for their ability to enhance neutrophil killing. IgG2 antibodies, particularly those targeting in vivo-grown bacteria, showed the highest opsonising activity, crucial for fighting S. aureus infections.
Area of Science:
- Veterinary Immunology
- Bacterial Pathogenesis
- Immunoglobulin Function
Background:
- Staphylococcus aureus poses a significant threat to mammary health in sheep.
- Understanding the opsonising activity of specific antibody isotypes is crucial for developing effective vaccines.
Purpose of the Study:
- To compare the opsonising activity of sheep IgG1 and IgG2 antibodies against Staphylococcus aureus.
- To investigate the role of bacterial growth conditions (in vitro vs. in vivo) on antibody efficacy.
Main Methods:
- Assay of opsonising activity using ovine mammary neutrophils as effector cells.
- Testing blood serum, milk whey, and purified IgG1/IgG2 antibody preparations.
- Utilizing Staphylococcus aureus vaccines (live or killed) for sheep immunization.
Main Results:
- Sheep serum exhibited higher opsonising activity than milk whey.
- IgG2 antibodies against in vitro-grown S. aureus surface antigens showed greater opsonising activity than IgG1.
- The most potent opsonising activity was linked to IgG2 antibodies targeting pseudocapsular antigens from in vivo-grown S. aureus.
Conclusions:
- Ovine IgG2 antibodies, especially those targeting in vivo-expressed antigens, are key mediators of opsonisation against Staphylococcus aureus.
- Vaccine strategies should consider targeting antigens produced by bacteria under in vivo conditions for optimal efficacy.