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Monocyte chemoattractant protein 1 acts as a T-lymphocyte chemoattractant
Insights
Monocyte chemoattractant protein 1 (MCP-1) also attracts T lymphocytes, not just monocytes. This finding helps explain the co-localization of these immune cells at inflammation sites.
Area of Science:
- Immunology
- Cell Biology
Background:
- Monocyte chemoattractant protein 1 (MCP-1) was previously believed to attract only monocytes.
- Understanding immune cell migration is crucial for studying inflammatory responses.
Purpose of the Study:
- To identify and characterize lymphocyte chemoattractants in mitogen-stimulated peripheral blood mononuclear cells.
- To determine if MCP-1 attracts T lymphocytes.
Main Methods:
- Transendothelial lymphocyte chemotaxis assay.
- Amino acid sequence analysis.
- Recombinant MCP-1 chemoattraction assays.
- Antibody neutralization assays.
Main Results:
- Amino acid sequencing identified the chemoattractant as MCP-1.
- Recombinant MCP-1 demonstrated chemoattraction for purified T lymphocytes and CD3+ lymphocytes.
- T-lymphocyte response was dose-dependent and chemotactic.
- Chemoattracted T lymphocytes were identified as an activated memory subset.
- MCP-1's T-lymphocyte chemoattractant activity was confirmed independently of endothelial cells.
- Antibody to MCP-1 neutralized the majority of T-lymphocyte chemotactic activity.
Conclusions:
- MCP-1 is a major chemoattractant secreted by stimulated peripheral blood mononuclear cells.
- MCP-1 acts as a potent chemoattractant for both T lymphocytes and monocytes.
- This dual chemoattractant role of MCP-1 may explain the co-occurrence of monocytes and memory T lymphocytes at inflammatory sites.
Abstract:
We have utilized a transendothelial lymphocyte chemotaxis assay to identify and purify a lymphocyte chemoattractant in supernatants of mitogen-stimulated peripheral blood mononuclear cells. Amino acid sequence analysis revealed identity with monocyte chemoattractant protein 1 (MCP-1), a chemoattractant previously thought to be specific for monocytes. Recombinant MCP-1 is chemoattractive for purified T lymphocytes and for CD3+ lymphocytes in peripheral blood lymphocyte preparations. The T-cell response to MCP-1 is dose-dependent and chemotactic, rather than chemokinetic. Phenotyping of chemoattracted T lymphocytes shows they are an activated memory subset. The response to MCP-1 by T lymphocytes can be duplicated in the absence of an endothelial monolayer and the majority of T-lymphocyte chemotactic activity in mitogen-stimulated peripheral blood mononuclear cell supernatants can be neutralized by antibody to MCP-1. Thus, MCP-1 is the major lymphocyte chemoattractant secreted by mitogen-stimulated peripheral blood mononuclear cells and is capable of acting as a potent T-lymphocyte, as well as monocyte, chemoattractant. This may help explain why monocytes and T lymphocytes of the memory subset are always found together at sites of antigen-induced inflammation.