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Sendai virus glycoproteins are T cell-dependent B cell mitogens
Abstract:
UV-inactivated Sendai virus is mitogenic for murine splenocytes, whereas infectious Sendai virus kills spleen cells in vitro. The isolated hemagglutinin-neuraminidase (HN) and fusion (F) glycoproteins of Sendai virus are also mitogenic for cultured mouse spleen cells. A mixture of these glycoproteins (1 microgram/well) gives maximum stimulation 96 h after culture initiation. Viral proteins remaining insoluble after Triton X-100 extraction are also mitogenic for mouse spleen cells, with maximum stimulation occurring at 72 h after culture initiation with 1 to 5 microgram/well. On the basis of protein concentration, the HN and F glycoproteins are approximately three times more mitogenic than the Triton X-100-insoluble material. The mitogenic response of the HN and F glycoproteins has two components, a T cell-independent B cell proliferation, which is less than one-half of the total stimulation observed, and a T cell-dependent B cell proliferation. In contrast, the Triton X-100-insoluble material is a T cell-dependent B cell mitogen. Purified T lymphocytes do not respond to the mitogenic signal of either HN-F or Triton X-100-insoluble material.
Insights
Sendai virus glycoproteins (HN and F) and insoluble viral proteins stimulate mouse spleen cells. The glycoproteins are more potent mitogens, inducing both T cell-dependent and independent B cell proliferation.
Area of Science:
- Immunology
- Virology
Background:
- Sendai virus, a paramyxovirus, has complex interactions with host immune cells.
- UV-inactivated Sendai virus is known to activate lymphocytes, but the specific viral components responsible are not fully elucidated.
Purpose of the Study:
- To investigate the mitogenic properties of specific Sendai virus components on murine splenocytes.
- To differentiate the immune response pathways triggered by different viral fractions.
Main Methods:
- Isolation and purification of hemagglutinin-neuraminidase (HN) and fusion (F) glycoproteins from Sendai virus.
- Extraction of Triton X-100 insoluble viral proteins.
- In vitro culture of murine splenocytes with viral components.
- Assessment of cell proliferation and T cell dependency.
Main Results:
- Both isolated HN and F glycoproteins and Triton X-100 insoluble viral proteins exhibit mitogenic activity on mouse spleen cells.
- HN and F glycoproteins are approximately three times more potent mitogens than the insoluble fraction.
- HN and F glycoproteins induce both T cell-independent and T cell-dependent B cell proliferation.
- The Triton X-100 insoluble fraction acts as a T cell-dependent B cell mitogen.
- Purified T lymphocytes did not respond to either mitogenic stimulus.
Conclusions:
- Sendai virus glycoproteins (HN and F) and insoluble viral proteins are potent mitogens for murine splenocytes.
- These viral components differentially activate B cell proliferation pathways, involving both T cell-dependent and independent mechanisms.
- The findings provide insights into the immunomodulatory functions of Sendai virus components.