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Development and Function of Protective and Pathologic Memory CD4 T Cells.

Jaigirdar SA, MacLeod MK - Front Immunol (2015)

Bottom Line: As key orchestrators and mediators of immunity, CD4 T cells are central to the vast majority of adaptive immune responses.Generated following an immune response, memory CD4 T cells retain pertinent information about their activation environment enabling them to make rapid effector responses upon reactivation.A greater understanding of these factors has the potential to aid the design of more effective vaccines and to improve regulation of pathologic CD4 T cells, such as in the context of autoimmunity and allergy.

View Article: PubMed Central - PubMed

Affiliation: Centre for Immunobiology, Institute of Infection, Immunity and Inflammation, University of Glasgow , Glasgow , UK.

ABSTRACT
Immunological memory is one of the defining features of the adaptive immune system. As key orchestrators and mediators of immunity, CD4 T cells are central to the vast majority of adaptive immune responses. Generated following an immune response, memory CD4 T cells retain pertinent information about their activation environment enabling them to make rapid effector responses upon reactivation. These responses can either benefit the host by hastening the control of pathogens or cause damaging immunopathology. Here, we will discuss the diversity of the memory CD4 T cell pool, the signals that influence the transition of activated T cells into that pool, and highlight how activation requirements differ between naïve and memory CD4 T cells. A greater understanding of these factors has the potential to aid the design of more effective vaccines and to improve regulation of pathologic CD4 T cells, such as in the context of autoimmunity and allergy.

No MeSH data available.


Related in: MedlinePlus

Heterogeneity in memory CD4 T cells. Memory CD4 T cells can be found in lymphoid organs, blood, and at tissue sites. Stem cell memory T cells (Tscm) and central memory T (Tcm) cells are found in lymphoid organs and in the blood. Both populations are relatively undifferentiated compared to other memory CD4 T cell subsets, and are long lived. Follicular helper memory T (Tfh) cells can also be found in the blood and lymphoid organs. They express the B cell follicle homing receptor, CXCR5, which can position them near B cell follicles to provide rapid B cell help upon reactivation. Effector memory (Tem) and tissue resident memory T (Trm) cells can both be found in peripheral tissues and are more differentiated than Tcm and Tscm. Tem are migratory, passing through tissues and the blood, while Trm are restricted to tissues. Both populations can respond rapidly to tissue invading pathogens (15, 17, 23–27).
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Figure 1: Heterogeneity in memory CD4 T cells. Memory CD4 T cells can be found in lymphoid organs, blood, and at tissue sites. Stem cell memory T cells (Tscm) and central memory T (Tcm) cells are found in lymphoid organs and in the blood. Both populations are relatively undifferentiated compared to other memory CD4 T cell subsets, and are long lived. Follicular helper memory T (Tfh) cells can also be found in the blood and lymphoid organs. They express the B cell follicle homing receptor, CXCR5, which can position them near B cell follicles to provide rapid B cell help upon reactivation. Effector memory (Tem) and tissue resident memory T (Trm) cells can both be found in peripheral tissues and are more differentiated than Tcm and Tscm. Tem are migratory, passing through tissues and the blood, while Trm are restricted to tissues. Both populations can respond rapidly to tissue invading pathogens (15, 17, 23–27).

Mentions: More recently, additional memory cell subgroups have been described (Figure 1), suggesting further heterogeneity in the steps between activated and memory T cell. While all memory cells are by definition long lived, memory stem T cells (Tscm) perhaps represent the most stable subset (18–21). The majority of studies on Tscm have been carried out on human peripheral blood cells, where Tscm express makers of naïve (CD45RA+) and memory (CXCR3 and CD95+) cells. Analysis of antigen-specific CD8 Tscm demonstrates that these cells have previously responded to antigen, can self-renew, and rapidly differentiate into cytokine producing effector cells upon reactivation (18–22). Transcriptional analysis of human CD4 T cell populations identified using CD45RO, CCR7, and CD95, has positioned Tscm as a distinct population with a profile somewhat in-between naïve and Tcm cells (23).


Development and Function of Protective and Pathologic Memory CD4 T Cells.

Jaigirdar SA, MacLeod MK - Front Immunol (2015)

Heterogeneity in memory CD4 T cells. Memory CD4 T cells can be found in lymphoid organs, blood, and at tissue sites. Stem cell memory T cells (Tscm) and central memory T (Tcm) cells are found in lymphoid organs and in the blood. Both populations are relatively undifferentiated compared to other memory CD4 T cell subsets, and are long lived. Follicular helper memory T (Tfh) cells can also be found in the blood and lymphoid organs. They express the B cell follicle homing receptor, CXCR5, which can position them near B cell follicles to provide rapid B cell help upon reactivation. Effector memory (Tem) and tissue resident memory T (Trm) cells can both be found in peripheral tissues and are more differentiated than Tcm and Tscm. Tem are migratory, passing through tissues and the blood, while Trm are restricted to tissues. Both populations can respond rapidly to tissue invading pathogens (15, 17, 23–27).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4561815&req=5

Figure 1: Heterogeneity in memory CD4 T cells. Memory CD4 T cells can be found in lymphoid organs, blood, and at tissue sites. Stem cell memory T cells (Tscm) and central memory T (Tcm) cells are found in lymphoid organs and in the blood. Both populations are relatively undifferentiated compared to other memory CD4 T cell subsets, and are long lived. Follicular helper memory T (Tfh) cells can also be found in the blood and lymphoid organs. They express the B cell follicle homing receptor, CXCR5, which can position them near B cell follicles to provide rapid B cell help upon reactivation. Effector memory (Tem) and tissue resident memory T (Trm) cells can both be found in peripheral tissues and are more differentiated than Tcm and Tscm. Tem are migratory, passing through tissues and the blood, while Trm are restricted to tissues. Both populations can respond rapidly to tissue invading pathogens (15, 17, 23–27).
Mentions: More recently, additional memory cell subgroups have been described (Figure 1), suggesting further heterogeneity in the steps between activated and memory T cell. While all memory cells are by definition long lived, memory stem T cells (Tscm) perhaps represent the most stable subset (18–21). The majority of studies on Tscm have been carried out on human peripheral blood cells, where Tscm express makers of naïve (CD45RA+) and memory (CXCR3 and CD95+) cells. Analysis of antigen-specific CD8 Tscm demonstrates that these cells have previously responded to antigen, can self-renew, and rapidly differentiate into cytokine producing effector cells upon reactivation (18–22). Transcriptional analysis of human CD4 T cell populations identified using CD45RO, CCR7, and CD95, has positioned Tscm as a distinct population with a profile somewhat in-between naïve and Tcm cells (23).

Bottom Line: As key orchestrators and mediators of immunity, CD4 T cells are central to the vast majority of adaptive immune responses.Generated following an immune response, memory CD4 T cells retain pertinent information about their activation environment enabling them to make rapid effector responses upon reactivation.A greater understanding of these factors has the potential to aid the design of more effective vaccines and to improve regulation of pathologic CD4 T cells, such as in the context of autoimmunity and allergy.

View Article: PubMed Central - PubMed

Affiliation: Centre for Immunobiology, Institute of Infection, Immunity and Inflammation, University of Glasgow , Glasgow , UK.

ABSTRACT
Immunological memory is one of the defining features of the adaptive immune system. As key orchestrators and mediators of immunity, CD4 T cells are central to the vast majority of adaptive immune responses. Generated following an immune response, memory CD4 T cells retain pertinent information about their activation environment enabling them to make rapid effector responses upon reactivation. These responses can either benefit the host by hastening the control of pathogens or cause damaging immunopathology. Here, we will discuss the diversity of the memory CD4 T cell pool, the signals that influence the transition of activated T cells into that pool, and highlight how activation requirements differ between naïve and memory CD4 T cells. A greater understanding of these factors has the potential to aid the design of more effective vaccines and to improve regulation of pathologic CD4 T cells, such as in the context of autoimmunity and allergy.

No MeSH data available.


Related in: MedlinePlus