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.
Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland. kosmacz@iitd.pan.wroc.pl
Agata
A
Kosmaczewska
Lidia
L
Ciszak
Stanisław
S
Potoczek
Irena
I
Frydecka
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