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Poliovirus-induced suppression of lymphocyte stimulation: a macrophage-mediated effect
Abstract:
Poliovirus was shown to suppress the in vitro response of human mononuclear blood cells stimulated with phytohaemagglutinin (PHA), pokeweed mitogen (PWM), tuberculin purified protein derivative (PPD) or allogeneic cells. The suppression required infectious virus and the presence of macrophages. Experiments with combined cultures of human lymphocytes stimulated with PHA, PWM, PPD or allogeneic cells, and different numbers of autologous macrophages indicated that both lymphocyte stimulation and the inhibitory effect of poliovirus increased with increasing ratio of macrophages to lymphocytes. The response of human lymphocytes to PHA also was enhanced when autologous macrophages were replaced with murine macrophages. Mouse hepatitis virus inhibited this enhancing effect whereas poliovirus failed to do so. The findings confirm our previous suggestion that poliovirus inhibits stimulation of lymphocytes by suppressing the enhancing effect of macrophages.
Insights
Poliovirus infection suppresses human immune cell responses by impairing macrophage function. This study reveals poliovirus inhibits lymphocyte activation, particularly with increased macrophage presence, impacting cellular immunity.
Area of Science:
- Immunology
- Virology
- Cell Biology
Background:
- Poliovirus is known to affect the immune system.
- Previous research suggested poliovirus may interfere with lymphocyte responses.
Purpose of the Study:
- To investigate the mechanism by which poliovirus suppresses in vitro immune responses of human mononuclear blood cells.
- To determine the role of macrophages in poliovirus-induced immune suppression.
Main Methods:
- Human mononuclear blood cells were stimulated with various mitogens (phytohaemagglutinin, pokeweed mitogen) and antigens (purified protein derivative, allogeneic cells).
- The effect of infectious poliovirus and varying ratios of autologous macrophages on lymphocyte stimulation was assessed.
- Murine macrophages were used to further elucidate the role of macrophages, with comparisons to mouse hepatitis virus.
Main Results:
- Poliovirus significantly suppressed the in vitro response of human lymphocytes to PHA, PWM, PPD, and allogeneic cells.
- This suppression was dependent on infectious poliovirus and the presence of macrophages.
- Both lymphocyte stimulation and poliovirus inhibition increased with higher macrophage-to-lymphocyte ratios.
- Poliovirus did not inhibit the enhancing effect of murine macrophages on lymphocyte response, unlike mouse hepatitis virus.
Conclusions:
- Poliovirus inhibits human lymphocyte stimulation by suppressing the enhancing function of macrophages.
- The findings confirm that macrophages are critical mediators in poliovirus-induced immunosuppression.