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MLR3 molecule is an activation antigen shared by human B, T lymphocytes and T cell precursors
A Risso1, M E Cosulich, A Rubartelli
1Instituto scientifico Tumori, Genova, Italy.
Abstract:
MLR3 molecule is a membrane glycoprotein (mol. mass range 28-34 kDa) present on activated, but not resting human peripheral T cells, B cells and thymocytes. Its kinetics of appearance on the cell surface (3 h after the addition of the inductive signal to the cells) suggests that it is an early activation antigen. The proliferative response of cultured T and B lymphocytes and thymocytes to different activation signals is inhibited by the addition of MLR3 monoclonal antibody. Moreover the antibody in combination with non-mitogenic doses of phorbol myristate acetate leads to proliferation of thymocytes and resting B and T lymphocytes. In the latter, synthesis of interleukin 2 is also induced. Biochemical analysis of MLR3 antigen indicates that it is a phosphorylated protein with N-linked sugar moieties. Together these data suggest a role for MLR3 antigen in the signal transduction process during activation, both for mature lymphocytes and for T cell precursors.
Insights
The MLR3 molecule, an early activation antigen, is crucial for human lymphocyte and thymocyte activation. Its monoclonal antibody inhibits proliferation but can also induce it, suggesting a role in signal transduction.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- MLR3 molecule is a membrane glycoprotein found on activated human T cells, B cells, and thymocytes.
- It appears early (3 hours) after cellular activation, indicating its role as an early activation antigen.
Purpose of the Study:
- To investigate the function of the MLR3 molecule in lymphocyte and thymocyte activation.
- To explore the role of MLR3 in signal transduction pathways.
Main Methods:
- Utilized monoclonal antibodies against MLR3.
- Performed cell culture experiments with activation signals and phorbol myristate acetate.
- Conducted biochemical analysis of the MLR3 antigen.
Main Results:
- MLR3 monoclonal antibody inhibited the proliferative response of activated T and B lymphocytes and thymocytes.
- The antibody, with phorbol myristate acetate, induced proliferation in resting lymphocytes and thymocytes.
- Interleukin 2 synthesis was induced in resting T lymphocytes.
Conclusions:
- MLR3 antigen plays a significant role in the signal transduction process during lymphocyte and thymocyte activation.
- MLR3 is involved in both the inhibition and induction of cellular proliferation.
- The findings suggest MLR3 is a key player in immune cell activation pathways.