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Dual effect of meningococcal antigens on a T cell dependent immune response
Abstract:
Meningococcal antigens (MA) showed adjuvant activity when administered to mice at the same time as antigen (sheep erythrocyte (SE], by increasing the splenocyte plaque-forming response in a dose-related manner. However, when SE were given 1 day after MA administration, the subsequent plaque formation was diminished from normal in proportion to the dose of MA injected. Splenocytes taken from mice up to 5 days after MA injection actively inhibited plaque formation when mixed with splenocytes immunized with SE 4 days earlier. Two days after MA injection the nonspecific inhibition of plaque formation was mainly due to adherent spleen cells, while at 5 days nonadherent cells had acquired the inhibitory activity. It appears that it is the degree of activation of adherent cells resulting from the timing and dosage of MA which modulates the subsequent development and secretion of antibody-forming cells.
Insights
Meningococcal antigens (MA) can boost immune responses when given with other antigens. However, timing is critical, as MA can suppress antibody formation if given before the antigen, involving spleen cell modulation.
Area of Science:
- Immunology
- Vaccinology
Background:
- Meningococcal antigens (MA) are known to elicit immune responses.
- The adjuvant activity of MA, particularly in relation to timing and dosage, requires further elucidation.
Purpose of the Study:
- To investigate the immunomodulatory effects of meningococcal antigens (MA) on antibody production.
- To determine how the timing of MA administration relative to a model antigen (sheep erythrocytes, SE) influences immune responses.
Main Methods:
- Mice were immunized with SE, with or without concurrent or sequential administration of MA.
- Splenocyte proliferation and plaque-forming cell assays were used to assess immune responses.
- In vitro assays were performed to evaluate the inhibitory effects of splenocytes from MA-treated mice.
Main Results:
- MA demonstrated dose-dependent adjuvant activity when co-administered with SE, enhancing the plaque-forming response.
- Sequential administration of MA before SE resulted in suppressed plaque formation.
- Splenocytes from MA-treated mice exhibited inhibitory activity against SE-specific antibody production, with a shift from adherent to non-adherent cells over time.
Conclusions:
- The timing and dosage of meningococcal antigens critically influence their immunomodulatory effects.
- MA can act as an adjuvant or an immunosuppressant depending on administration timing relative to antigen exposure.
- Adherent spleen cells play a key role in MA-induced suppression early after administration, with non-adherent cells becoming involved later.