Activation of CD4+ CD25+ regulatory T cell suppressor function by analogs of the selecting peptide

Joseph Larkin1, Cristina Cozzo Picca, Andrew J Caton

  • 1The Wistar Institute, Philadelphia, PA 19104, USA.

CD4+ CD25+ Foxp3+ regulatory T (Treg) cells can undergo both thymic selection and peripheral expansion in response to self peptides that are agonists for their T cell receptors (TCR). However, the specificity by which these TCR must recognize peptide:MHC complexes to activate Treg cell function is not known. We show that CD4+ CD25+ Foxp3+ Treg cells can mediate suppression in response to peptides that are only weakly cross-reactive with the self peptide that induced their formation in vivo. Moreover, suppression could be efficiently activated by peptide analogs that were inefficient at inducing CD69 up-regulation, and that also induced little or no proliferation of naïve CD4+ CD25- Foxp3- T cells expressing the same TCR. These findings provide evidence that self peptide-specific CD4+ CD25+ Foxp3+ Treg cells can exert regulatory function in response to self- and/or pathogen-derived peptides with which they are only weakly cross-reactive.

Related Concept Videos

T Cell Activation and Clonal Selection01:22

T Cell Activation and Clonal Selection

T cells are integral to our adaptive immune system, recognizing and effectively responding to foreign antigens. T cell activation and clonal selection are pivotal in orchestrating this immune response. This article elucidates these mechanisms, detailing the roles of cluster of differentiation (CD) markers, major histocompatibility complex (MHC) molecules, costimulatory signals, and the process of clonal selection.
Naive T cells that have not yet encountered an antigen express two primary CD...
T Cell Types and Functions01:24

T Cell Types and Functions

When T cells with CD4 markers are activated, they give rise to two types of effector cells: helper T cells and regulatory T cells. Meanwhile, T cells with CD8 markers differentiate into effector cytotoxic T cells. The differentiation of CD4 T cells into helper T cell subsets, such as Th1, Th2, and Th17 cells, is dependent on the antigen type, antigen-presenting cell, and regulatory cytokines.
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
Cytotoxic T Cells-mediated Immune Response01:27

Cytotoxic T Cells-mediated Immune Response

Cytotoxic T cells are a vital component of the immune system. They have the remarkable ability to identify and target antigens on infected or abnormal cells. These antigens often originate from intracellular pathogens such as viruses or abnormal proteins cancer cells produce.
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...