The significance of Treg cells in defective tumor immunity.
Regulatory T cells (Treg) enriched in FoxP3+, glucocorticoid-induced TNF receptor+, and cytotoxic T-lymphocyte-associated antigen-4+ exert a potential to suppress effector T cells in the periphery. These cells exist in markedly higher proportions within tumor-infiltrating lymphocytes, peripheral blood lymphocytes, and/or regional lymph node lymphocytes of patients with cancer and their frequencies are suggested to be strongly related to tumor progression and inversely correlated with the efficacy of treatment. Tumor-specific Treg cells require ligand-specific activation and cell-to-cell contact to exert their suppressive activity on tumor-specific effector cells (CD8+ cytotoxic T lymphocytes and CD4+ Th cells), which includes decreased cytotoxity, proliferation, and Th1 cytokine secrection. Depletion or blockade of Treg cells can enhance immune protection from tumor-associated antigens that are expressed as self antigens. Recent studies revealed that lymphoma T cells might adopt a Treg profile as well. Studies assessing the influence of chemotherapy on Treg cells have also been included in this review.
Kosmaczewska
Agata
A
Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland. kosmacz@iitd.pan.wroc.pl
Ciszak
Lidia
L
Potoczek
Stanisław
S
Frydecka
Irena
I
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D049109:Cell Proliferation; D016207:Cytokines / Q000276:immunology / Q000378:metabolism*; D051858:Forkhead Transcription Factors / Q000378:metabolism; D006801:Humans; D007108:Immune Tolerance; D008024:Ligands; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology / Q000378:metabolism; D009369:Neoplasms / Q000276:immunology* / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000502:physiology
D016207:Cytokines; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D008024:Ligands