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Differential down‐regulation of CD95 or CD95L in chronically HIV‐infected cells of monocytic or lymphocytic origin: cellular studies and molecular analysis by quantitative competitive RT‐PCR
Author(s) -
Pinti Marcello,
Pedrazzi Jessica,
Benatti Francesca,
Sorrentino Veronica,
Nuzzo Cira,
Cavazzuti Valeria,
Biswas Priscilla,
Petrusca Daniela Nicoleta,
Mussini Cristina,
De Rienzo Bruno,
Cossarizza Andrea
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01131-x
Subject(s) - u937 cell , ionomycin , cell culture , biology , microbiology and biotechnology , thp1 cell line , gene expression , virus , fas receptor , jurkat cells , cell , intracellular , apoptosis , t cell , virology , immunology , gene , immune system , programmed cell death , biochemistry , genetics
We analysed the expression of CD95/CD95L in two widely used models for studying the cellular effects of chronic infection with human immunodeficiency virus type 1 (HIV‐1), i.e. ACH‐2 cells, derived from the lymphocytic cell line A301, and U1, derived from monocytic U937 cells. A301 and ACH‐2 mounted the same amount of plasma membrane CD95, while U1 had a consistent decrease in CD95 expression. Using different antibodies, we failed to detect the plasma membrane form of its ligand, CD95L, but we could see the intracellular presence of that molecule in A301 cells and, to a lesser extent, in ACH‐2 cells, but not in U937 or U1 cells. To confirm the cytofluorimetric data and quantify the expression of CD95L at the RNA level, we developed a quantitative competitive RT‐PCR assay. The HUT78 cell line had about 50 000 copies mRNA/1000 cells, three times more after induction with a phorbol ester and ionomycin. ACH‐2 expressed about 400‐ (basal) or 10‐ (induced) fold less CD95L mRNA than the parental cell line A301; U937 and U1 were below the limit of detection. In cells of lymphoid origin (ACH‐2) chronic HIV infection inhibits the expression of CD95L, the phenomenon occurring at the transcriptional level. In cells of monocytic origin (U1) the infection decreases the plasma membrane expression of CD95. This suggests that HIV could trigger different anti‐apoptotic strategies which likely depend upon the cell line which is infected. In monocytic cells which act as a viral reservoir, the expression of the molecule whose binding triggers apoptosis decreases, while in lymphoid cells, capable of exerting cytotoxicity, the expression of a molecule which induces apoptosis is reduced.