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Modulation of IgM to IgG class switch by protein A
B N Paul1, A K Saxena, P K Ray
1Immunobiology Laboratory, Industrial Toxicology Research Centre, Lucknow, India.
International Journal of Immunopharmacology
|July 1, 1992
Summary
Soluble protein A (SpA) differentially modulated host immunoglobulin G (IgG) levels. SpA dose-dependently impacted B-cell responses to sheep erythrocyte antigen (SRBC), affecting both primary and secondary immune reactions.
Area of Science:
- Immunology
- Microbiology
Background:
- Soluble protein A (SpA) from Staphylococcus aureus binds to IgG, influencing host IgG levels based on dose.
- Previous studies show low doses of SpA decrease IgG, while high doses increase it.
Purpose of the Study:
- To investigate the impact of SpA-induced IgG modulation on B-cell responses to sheep erythrocyte antigen (SRBC) in mice.
- To elucidate the role of IgG levels in primary and secondary B-cell immune responses.
Main Methods:
- Administration of varying doses of SpA (5, 10, 25 micrograms) to Balb/c mice at the time of primary or secondary antigenic challenge with SRBC.
- Measurement of IgM and IgG antibody-secreting cell (PFC) responses to assess B-cell activation and differentiation.
Main Results:
- SpA administration during primary challenge inhibited both primary IgM and secondary IgM/IgG responses in a dose-dependent manner.
- SpA administration during secondary challenge with 5 and 10 micrograms maintained IgM responses, but 25 micrograms inhibited both IgM and IgG PFC responses.
Conclusions:
- SpA's dose-dependent effects on IgG levels significantly influence B-cell maturation and immunoglobulin class switching.
- These findings provide insights into the regulatory mechanisms governing B-cell responses during adaptive immunity.