Expression of CTLA-4 molecule in peripheral blood T lymphocytes from patients with systemic lupus erythematosus.
CTLA-4 is a cell surface molecule expressed on activated T cells that is suggested to deliver a negative signal for T cell activation. Since CTLA-4 might be a negative regulator of autoimmune diseases, we investigated its expression on T cells from 20 patients with systemic lupus erythematosus (SLE) by flow cytometric analysis and RT-PCR. We found that although CTLA-4 mRNA was readily detected in all patients and controls, only a very minor subset of T cells expressed detectable surface CTLA-4 molecules in both groups. But patients with SLE had significantly increased percentages of CTLA-4-positive T cells compared with normal controls, implying at least that there was no apparent defective expression of CTLA-4 molecule in human lupus. The kinetics of CTLA-4 expression on T cells stimulated in vitro with PMA plus ionomycin were similar in normal controls and patients with SLE. The expression of CTLA-4 molecules after stimulation increased gradually and peaked at 72 hr. However, the induction of CTLA-4 expression on patients' T cells appeared to be weaker than that of normal individuals. Whether this reflects impaired downregulation by CTLA-4 molecules in SLE patients needs to be clarified further.
Liu
M F
MF
Department of Internal Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan, R.O.C.
Liu
H S
HS
Wang
C R
CR
Lei
H Y
HY
D000069594:Abatacept; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000096:biosynthesis* / Q000235:genetics; D000954:Antigens, Surface / Q000096:biosynthesis; D060908:CTLA-4 Antigen; D005260:Female; D006801:Humans; D018796:Immunoconjugates; D015759:Ionomycin / Q000494:pharmacology; D007700:Kinetics; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008180:Lupus Erythematosus, Systemic / Q000097:blood*; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015854:Up-Regulation
D015703:Antigens, CD; D000943:Antigens, Differentiation; D000954:Antigens, Surface; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D018796:Immunoconjugates; D012333:RNA, Messenger; D015759:Ionomycin; D000069594:Abatacept; D013755:Tetradecanoylphorbol Acetate