Functional modifications of cytotoxic T-lymphocyte T200 glycoprotein recognized by monoclonal antibodies
Abstract:
Plasma membrane glycoproteins of cytotoxic T lymphocytes (CTLs) are involved in the binding to and subsequent destruction of appropriate target cells. The electrophoretic profile of surface proteins of mature CTLs, particularly those of high relative molecular mass (Mr), is markedly different from that of naive peripheral T cells or non-cytolytic T cells, suggesting the possible involvement of these molecules in the activation of CTLs and/or in the lytic process itself. By generating monoclonal antibodies to cell-surface proteins of CTL clones, we have now detected CTL-specific modifications in one of these high-Mr membrane proteins, T200. Although forms of T200 are found on a wide variety of cell types, the neoantigenic determinants recognized by our antibodies are present exclusively on activated T cells and in high concentrations only on CTLs. Furthermore, the expression of the modifications recognized by our antibodies is influenced by soluble factors and also seems to have functional significance, as monoclonal antibodies specific for these novel epitopes block cytolytic activity.
Insights
Cytotoxic T lymphocytes (CTLs) utilize specific T200 protein modifications on their surface for target cell destruction. These modifications, exclusive to activated T cells, are crucial for CTL function and can be blocked by antibodies.
Area of Science:
- Immunology
- Cell Biology
Background:
- Plasma membrane glycoproteins on cytotoxic T lymphocytes (CTLs) mediate target cell binding and destruction.
- Distinct surface protein profiles, especially high molecular mass (Mr) proteins, differentiate mature CTLs from naive or non-cytolytic T cells, suggesting roles in activation or lysis.
Purpose of the Study:
- To investigate specific modifications of high-Mr membrane proteins in cytotoxic T lymphocytes (CTLs).
- To identify CTL-specific surface protein alterations involved in T cell activation and cytolytic function.
Main Methods:
- Generation of monoclonal antibodies against cell-surface proteins of CTL clones.
- Analysis of T200 protein modifications using monoclonal antibody recognition of neoantigenic determinants.
- Assessment of antibody blockade of cytolytic activity.
Main Results:
- CTLs exhibit specific modifications in the T200 membrane protein.
- These T200 neoantigenic determinants are exclusively found on activated T cells, with high concentrations on CTLs.
- Antibodies targeting these novel epitopes block CTL-mediated cytolytic activity.
Conclusions:
- The T200 protein undergoes CTL-specific modifications that are indicative of T cell activation.
- These modified T200 epitopes are crucial for the cytotoxic function of CTLs.
- Targeting these modifications offers a potential strategy to modulate CTL activity.
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