Regeneration and tolerance factor is expressed during T-lymphocyte activation and plays a role in apoptosis.
Regeneration and tolerance factor (RTF) is a protein cloned from the thymus and expressed on B lymphocytes in normal pregnancy, B lymphocytic leukemia lines, and T and B lymphocytes in individuals with HIV infection. Findings, using the Jurkat T-cell model, revealed that RTF is upregulated after activation and anti-RTF antibody-induced apoptosis. In this article anti-RTF antibody-induced apoptosis of both unstimulated and activated T lymphocytes. RTF expression was examined in human PBMC or purified T lymphocytes after their in vitro activation. Kinetic studies indicated maximal RTF cell surface expression on activated T lymphocytes occurred between expression of the early activation antigen CD69 and the IL-2alpha receptor (CD25) by multiparameter flow cytometry. RTF receptor expression correlated with Fas (CD95) and CD25 receptor expression (r2 = 0.6 and 0.5, respectively). RTF surface expression was dependent on the stimuli used to activate T lymphocytes. T lymphocytes obtained maximal RTF expression when activated through the TCR signal complex using anti-CD3epsilon antibody alone when compared with T lymphocytes activated with costimulation provided by anti-CD28 antibody alone or with anti-CD28 and anti-CD3epsilon antibody. RTF is expressed under conditions of both activation and anergy. The RTFs increased concentration on the surface of anergic T cells may protect these cells from apoptosis because increased RTF concentrations inhibited anti-RTF induced apoptosis. These data further characterize the expression of RTF on activated T lymphocytes and the role of anti-RTF antibody in T-lymphocyte apoptosis.
Boomer
J S
JS
Clinical Immunology Laboratory, Department of Microbiology/Immunology, Finch University of Health Sciences, The Chicago Medical School, North Chicago, IL 60064, USA.
Derks
R A
RA
Lee
G W
GW
DuChateau
B K
BK
Gilman-Sachs
A
A
Beaman
K D
KD
D017304:Annexin A5 / Q000096:biosynthesis; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD / Q000096:biosynthesis; D000945:Antigens, Differentiation, T-Lymphocyte / Q000096:biosynthesis; D017209:Apoptosis / Q000276:immunology*; D002462:Cell Membrane / Q000276:immunology; D006801:Humans; D019169:Jurkat Cells; D007700:Kinetics; D037181:Lectins, C-Type; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology*; D011257:Pregnancy Proteins / Q000096:biosynthesis* / Q000276:immunology; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D013491:Suppressor Factors, Immunologic / Q000096:biosynthesis* / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D019014:fas Receptor / Q000096:biosynthesis; D000099192:CD69 Antigens; D006180:Proton-Translocating ATPases
D017304:Annexin A5; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D037181:Lectins, C-Type; D011257:Pregnancy Proteins; D015375:Receptors, Interleukin-2; D013491:Suppressor Factors, Immunologic; D019014:fas Receptor; D000099192:CD69 Antigens; C525845:ATP6V0A2 protein, human; D006180:Proton-Translocating ATPases