TY - JOUR
T1 - A selective defect of IFN-γ- but not of IFN-α-induced JAK/STAT pathway in a subset of U937 clones prevents the antiretroviral effect of IFN-γ against HIV-1
AU - Bovolenta, Chiara
AU - Lorini, Alessandro L.
AU - Mantelli, Barbara
AU - Camorali, Laura
AU - Novelli, Francesco
AU - Biswas, Priscilla
AU - Poli, Guido
PY - 1999/1/1
Y1 - 1999/1/1
N2 - IFN-γ induces transcription of several IFN-stimulated genes (ISGs). Recently, the IFN-γ-dependent Janus kinase (JAK)/STAT pathway has been shown to mediate the activation of some ISGs, by the sequential phosphorylation of two JAK kinases (JAK1 and JAK2) and of STAT1. Given that the JAK/STAT is the major, but not the only pathway linked to the IFN-γR, aim of our work was to investigate the signal-transduction pathway(s) by which IFN-γ exerts its effects on acute replication of HIV in monocytic cells. To this end, we utilized clones previously derived from the U937 promonocytic cell line, differing for their efficient (plus clones) or inefficient (minus clones) abilities of supporting HIV replication. Unlike IFN-α, IFN-γ did not inhibit HIV replication in plus clones, whereas virus production in minus cells was efficiently inhibited by both types of IFN. Plus clones generated a JAK/STAT signal-transduction pathway in response to IFN-α, but not IFN-γ. In contrast, minus clones responded to either cytokines. The functional defect of plus clones in response to IFN-γ was correlated to a selective defect of IFN-γR2, but not IFN-γR1, membrane expression. Surprisingly enough, IFN-γ stimulation of plus clones induced IFN-stimulated gene factor 3 (ISGF3γ). These results strongly support the hypothesis that the JAK/STAT pathway is responsible for the antiretroviral effect of IFN-γ, and further provide evidence for a potential second pathway triggered by IFN-γ in the absence of IFN-γR2 chain cell surface expression and involving ISGF3γ.
AB - IFN-γ induces transcription of several IFN-stimulated genes (ISGs). Recently, the IFN-γ-dependent Janus kinase (JAK)/STAT pathway has been shown to mediate the activation of some ISGs, by the sequential phosphorylation of two JAK kinases (JAK1 and JAK2) and of STAT1. Given that the JAK/STAT is the major, but not the only pathway linked to the IFN-γR, aim of our work was to investigate the signal-transduction pathway(s) by which IFN-γ exerts its effects on acute replication of HIV in monocytic cells. To this end, we utilized clones previously derived from the U937 promonocytic cell line, differing for their efficient (plus clones) or inefficient (minus clones) abilities of supporting HIV replication. Unlike IFN-α, IFN-γ did not inhibit HIV replication in plus clones, whereas virus production in minus cells was efficiently inhibited by both types of IFN. Plus clones generated a JAK/STAT signal-transduction pathway in response to IFN-α, but not IFN-γ. In contrast, minus clones responded to either cytokines. The functional defect of plus clones in response to IFN-γ was correlated to a selective defect of IFN-γR2, but not IFN-γR1, membrane expression. Surprisingly enough, IFN-γ stimulation of plus clones induced IFN-stimulated gene factor 3 (ISGF3γ). These results strongly support the hypothesis that the JAK/STAT pathway is responsible for the antiretroviral effect of IFN-γ, and further provide evidence for a potential second pathway triggered by IFN-γ in the absence of IFN-γR2 chain cell surface expression and involving ISGF3γ.
UR - http://www.scopus.com/inward/record.url?scp=0032907269&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032907269&partnerID=8YFLogxK
M3 - Article
C2 - 9886402
AN - SCOPUS:0032907269
VL - 162
SP - 323
EP - 330
JO - Journal of Immunology
JF - Journal of Immunology
SN - 0022-1767
IS - 1
ER -