Enhanced expression of CTLA-4 (CD152) on CD4+ T cells in HIV infection.
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Enhanced expression of CTLA-4 (CD152) on CD4+ T cells in HIV infection. / Steiner, K; Waase, I; Rau, Thomas; Dietrich, M; Fleischer, B; Bröker, B M.
In: CLIN EXP IMMUNOL, Vol. 115, No. 3, 3, 1999, p. 451-457.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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TY - JOUR
T1 - Enhanced expression of CTLA-4 (CD152) on CD4+ T cells in HIV infection.
AU - Steiner, K
AU - Waase, I
AU - Rau, Thomas
AU - Dietrich, M
AU - Fleischer, B
AU - Bröker, B M
PY - 1999
Y1 - 1999
N2 - CTLA-4 (CD152) is a surface molecule of activated T cells with sequence homology to CD28. Both molecules bind to the same ligands, B7.1 (CD80) and B7.2 (CD86) but have antagonistic functions. While CD28 is an important costimulator, CTLA-4 has an essential inhibitory function in maintaining the homeostasis of the immune system. Down-regulation of CD28 predominantly on CD8+ T cells has been described in HIV infection, but analysis of CTLA-4 is complicated by its low expression levels. Here we have used potent signal enhancement to study CTLA-4 on peripheral blood mononuclear cells (PBMC) during HIV infection. CTLA-4 was expressed only on T cells. Expression levels were significantly increased selectively on CD4+ T cells during all stages of HIV infection, while CTLA-4 expression on CD8+ T cells was always low. In contrast, after stimulation with the mitogen phytohaemagglutinin (PHA), CTLA-4 levels were strongly increased on T cells from controls but in T cells from HIV patients this response was severely impaired. Our data suggest that in HIV infection CD4+ and CD8+ T cells may be less responsive to B7 costimuli due to two different mechanisms: increase in CTLA-4 expression by CD4+ cells and down-regulation of CD28 by CD8+ cells.
AB - CTLA-4 (CD152) is a surface molecule of activated T cells with sequence homology to CD28. Both molecules bind to the same ligands, B7.1 (CD80) and B7.2 (CD86) but have antagonistic functions. While CD28 is an important costimulator, CTLA-4 has an essential inhibitory function in maintaining the homeostasis of the immune system. Down-regulation of CD28 predominantly on CD8+ T cells has been described in HIV infection, but analysis of CTLA-4 is complicated by its low expression levels. Here we have used potent signal enhancement to study CTLA-4 on peripheral blood mononuclear cells (PBMC) during HIV infection. CTLA-4 was expressed only on T cells. Expression levels were significantly increased selectively on CD4+ T cells during all stages of HIV infection, while CTLA-4 expression on CD8+ T cells was always low. In contrast, after stimulation with the mitogen phytohaemagglutinin (PHA), CTLA-4 levels were strongly increased on T cells from controls but in T cells from HIV patients this response was severely impaired. Our data suggest that in HIV infection CD4+ and CD8+ T cells may be less responsive to B7 costimuli due to two different mechanisms: increase in CTLA-4 expression by CD4+ cells and down-regulation of CD28 by CD8+ cells.
M3 - SCORING: Zeitschriftenaufsatz
VL - 115
SP - 451
EP - 457
JO - CLIN EXP IMMUNOL
JF - CLIN EXP IMMUNOL
SN - 0009-9104
IS - 3
M1 - 3
ER -
