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Immunomodulating activity of meningococcal antigens
Abstract:
A preparation of meningococcal antigens (MA) extracted in CaCl2, and containing mostly outer membrane proteins, was strongly mitogenic for murine B lymphocytes. Given to mice in vitro, MA markedly impaired subsequent in vivo T-cell responses of splenocytes. Suppression of normal T splenocytes in vitro occurred with both adherent (Ad) and nonadherent (NA) splenocytes from MA-sensitized mice. B cells were much less affected by the suppression induced by MA, and only Ad cells could convey in vitro the low level impairment of B-cell proliferation. Strong T-cell suppression associated with a B-cell mitogen is also produced by bacillus Calmette-Guérin (BCG) and Corynebacterium parvum. The possible role of these phenomena in meningococcal disease is discussed.
Insights
Meningococcal antigens (MA) stimulate B cells but suppress T-cell responses in mice. This immune modulation by MA may play a role in meningococcal disease pathogenesis.
Area of Science:
- Immunology
- Microbiology
- Vaccinology
Background:
- Meningococcal antigens (MA) are primarily outer membrane proteins.
- MA are known to elicit immune responses.
Purpose of the Study:
- To investigate the immunomodulatory effects of meningococcal antigens (MA) on murine lymphocytes.
- To determine the impact of MA on T-cell and B-cell responses in vitro and in vivo.
Main Methods:
- Extraction of MA from Neisseria meningitidis using CaCl2.
- In vitro stimulation of murine splenocytes with MA.
- Assessment of T-cell and B-cell proliferation and function.
- Evaluation of adherent (Ad) and nonadherent (NA) splenocyte populations.
Main Results:
- MA demonstrated strong mitogenic activity for murine B lymphocytes.
- In vitro exposure to MA impaired subsequent in vivo T-cell responses.
- Suppression of T-cell responses involved both Ad and NA splenocytes from MA-sensitized mice.
- B cells were less affected, with Ad cells showing limited impairment of proliferation.
Conclusions:
- Meningococcal antigens possess potent immunomodulatory properties, acting as a B-cell mitogen while suppressing T-cell immunity.
- These findings suggest a potential mechanism by which meningococcal infections could evade host immune responses.
- The observed immune suppression by MA warrants further investigation into its role in meningococcal disease pathogenesis and potential implications for vaccine development.