Bcl-2 is expressed in human natural killer cells and is regulated by interleukin-2.
Bcl-2 is a major anti-apoptotic protein expressed in many normal and malignant cells. Recently, low to absent expression was reported in human natural killer (NK) cells cultured in serum-free media which could be induced with stem cell factor. We investigated the expression of bcl-2 protein of NK cells in normal blood donors and compared the bcl-2 expression in CD56+ NK cells with CD3+ T cells. To determine bcl-2 reactivity, a three-color flow-cytometric technique was used. CD56+ CD3- NK cells had an average bcl-2 expression of 83% compared with CD3+ T cells. CD56 and CD3 double positive T cells had an average content of 111% compared with all peripheral CD3+ T lymphocytes. When peripheral mononuclear cells were cultured with interleukin-2 (IL-2), bcl-2 could be upregulated by IL-2 in all cell populations studied. The induction of bcl-2 in these cell populations paralleled the induction in CD56- T lymphocytes cultured under identical conditions. The induction of bcl-2 by IL-2 was confirmed by Western blotting. The maximum induction of bcl-2 by IL-2 was observed at an IL-2 dose of 100-1,000 U/ml. Our data confirm the anti-apoptotic protein bcl-2 as an activation- or proliferation-associated marker of normal NK cells which can be induced by IL-2.
Jiang
S
S
Department of Hematology, MD Anderson Cancer Center, University of Texas, Houston, USA.
Munker
R
R
Andreeff
M
M
D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D017252:CD3 Complex / Q000097:blood; D019002:CD56 Antigen / Q000097:blood; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology / Q000502:physiology*; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis* / Q000187:drug effects; D013997:Time Factors; D019014:fas Receptor / Q000097:blood
D017252:CD3 Complex; D019002:CD56 Antigen; D016898:Interferon-alpha; D007376:Interleukin-2; D019253:Proto-Oncogene Proteins c-bcl-2; D019014:fas Receptor; D007371:Interferon-gamma