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CD31, a novel cell surface marker for CD4 cells of suppressor lineage, unaltered by state of activation
Y Torimoto1, D M Rothstein, N H Dang
1Division of Tumor Immunology, Dana-Farber Cancer Institute, Boston, MA 02115.
Insights
CD31 is a cell surface marker that distinguishes human CD4 cells into distinct functional subsets. CD31- CD4 cells provide helper functions, while CD31+ CD4 cells exhibit suppressor functions, offering a stable marker for immune cell lineage identification.
Area of Science:
- Immunology
- Cell Biology
Background:
- CD4 cells are crucial for adaptive immunity, with distinct subsets mediating helper or suppressor functions.
- Identifying stable markers for these CD4 cell subsets is essential for understanding immune responses.
Purpose of the Study:
- To investigate the role of CD31 as a cell surface marker for human CD4 cell subsets.
- To determine if CD31 expression differentiates functional CD4 cell populations.
Main Methods:
- Utilized a novel monoclonal antibody (mAb), anti-1F11, to detect CD31 expression on human CD4 cells.
- Analyzed CD31 expression on resting and activated CD4 cells, including subsets defined by CD45RA and CD45RO.
- Assessed functional activities such as B cell IgG synthesis, memory function, and cytokine production (IL-4).
Main Results:
- CD31 expression divides CD4 cells into distinct functional subpopulations.
- CD31- CD4 cells exhibit helper activity for B cell IgG synthesis and memory function.
- CD31+ CD4 cells demonstrate suppressor activity for B cell IgG synthesis and are responsive to Con A and autologous MHC.
- CD31 expression remains stable upon CD4 cell activation, unlike CD45RA.
Conclusions:
- CD31 serves as a reliable cell surface marker for defining human CD4+ T cell subsets with reciprocal functional programs (helper vs. suppressor).
- Unlike other markers, CD31's stable expression post-activation makes it valuable for identifying cells of suppressor or helper lineage.
Abstract:
In this study, we examined the role of CD31 as a cell surface marker for subsets of human CD4 cells. CD31, as defined by a newly developed mAb termed anti-1F11, can divide activated as well as resting CD4 cells into distinct functional subpopulations, based on its surface expression. Among CD4 cells freshly isolated from peripheral blood, anti-1F11 preferentially reacts with the CD45RA+ subset. The majority of helper activity for B cell IgG synthesis and memory function to recall Ag such as tetanus toxoid or mumps was found within the CD31- CD4 cell population, whereas CD31+ CD4 cells provided poor helper function for B cell IgG synthesis and were more responsive to Con A and autologous MHC (autologous MLR). The expression of CD31 on CD45RA+ CD4 cells did not change after activation, despite the loss of CD45RA from the cell surface. Conversely, CD31 was not acquired after activation of CD45RO+ CD45RA- CD4 cells. Furthermore, activated CD4 cells expressing CD31 can induce suppressor function for B cell IgG synthesis, whereas the reciprocal population of activated CD4 cells (CD31-) provide strong helper function for B cell IgG production. Finally, IL-4 production could only be induced by stimulation with PMA and ionomycin in either resting or activated CD31- CD4 cells. Thus, CD31 may prove useful in defining CD4 populations with reciprocal functional programs. Moreover, unlike other markers used for this purpose, the expression of CD31 does not change after activation and may serve as a more useful marker for identification of cells of suppressor or helper lineage.