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Phenotypic and functional effects of the motheaten gene on murine B and T lymphocytes
Abstract:
Lymphoid cells from C57BL/6 mice homozygous for the me gene exhibit multiple phenotypic and functional abnormalities from early as one week of age. In the B cell population these include a reduction in the frequency of detectable surface Ig+ cells, alterations in the level of expression of surface IgM and IgD, an increase in the frequency of large cells, plasma cells and TNP-specific plaque forming cePS. Together these findings provide strong evidence for polyclonal activation of B cells. The high level of expression of xenotropic MuLV gp70 by me/me spleen and lymph node cells provides further evidence for lymphoid cell activation. In preliminary studies, me/me T cells appeared to be phenotypically and functionally less affected by the me gene. The distribution of Thy 1.2 on the surface of spleen and lymph node T cells varied from low to normal and the mitogenic responses to Con A and PHA were depressed. It remains to be determined what the basic deficiency in me/me mice is and whether it affects primarily B cells or all lymphoid cells.
Insights
Mice with the me gene mutation show significant B cell abnormalities, including polyclonal activation and altered surface marker expression. T cells appear less affected, but further research is needed to identify the underlying genetic deficiency.
Area of Science:
- Immunology
- Genetics
- Mouse Models
Background:
- The me gene mutation in C57BL/6 mice leads to observable abnormalities in lymphoid cells from an early age.
- Understanding the specific cellular and molecular defects caused by the me gene is crucial for advancing immunology research.
Purpose of the Study:
- To investigate the phenotypic and functional consequences of the me gene mutation on B and T lymphocytes in mice.
- To determine if the me gene primarily affects B cells or all lymphoid cells.
Main Methods:
- Analysis of surface immunoglobulin (Ig) expression on B cells.
- Flow cytometry to assess cell populations (large cells, plasma cells).
- Measurement of TNP-specific plaque-forming cells.
- Evaluation of xenotropic MuLV gp70 expression.
- Assessment of T cell surface marker (Thy 1.2) distribution.
- Mitogenic response assays (Con A, PHA) for T cells.
Main Results:
- me/me mice exhibit reduced frequency of surface Ig+ cells and altered IgM/IgD expression.
- An increased frequency of large cells and plasma cells suggests B cell polyclonal activation.
- Elevated xenotropic MuLV gp70 expression on spleen and lymph node cells indicates lymphoid activation.
- me/me T cells show variable Thy 1.2 distribution and depressed mitogenic responses.
Conclusions:
- The me gene mutation strongly induces polyclonal B cell activation and lymphoid cell activation.
- While T cells appear less affected, some functional deficits are observed.
- The fundamental defect caused by the me gene requires further elucidation to determine its primary target—B cells or all lymphoid cells.