RESUMEN
The type I interferons (IFNs) are a family of cytokines with diverse biological activities, including antiviral, antiproliferative, and immunoregulatory functions. The discovery of the hormonally regulated, constitutively expressed IFNϵ has suggested a function for IFNs in reproductive tract homeostasis and protection from infections, but its intrinsic activities are untested. We report here the expression, purification, and functional characterization of murine IFNϵ (mIFNϵ). Recombinant mIFNϵ (rmIFNϵ) exhibited an α-helical fold characteristic of type I IFNs and bound to IFNα/ß receptor 1 (IFNAR1) and IFNAR2, but, unusually, it had a preference for IFNAR1. Nevertheless, rmIFNϵ induced typical type I IFN signaling activity, including STAT1 phosphorylation and activation of canonical type I IFN signaling reporters, demonstrating that it uses the JAK-STAT signaling pathway. We also found that rmIFNϵ induces the activation of T, B, and NK cells and exhibits antiviral, antiproliferative, and antibacterial activities typical of type I IFNs, albeit with 100-1000-fold reduced potency compared with rmIFNα1 and rmIFNß. Surprisingly, although the type I IFNs generally do not display cross-species activities, rmIFNϵ exhibited high antiviral activity on human cells, suppressing HIV replication and inducing the expression of known HIV restriction factors in human lymphocytes. Our findings define the intrinsic properties of murine IFNϵ, indicating that it distinctly interacts with IFNAR and elicits pathogen-suppressing activity with a potency enabling host defense but with limited toxicity, appropriate for a protein expressed constitutively in a sensitive mucosal site, such as the reproductive tract.
Asunto(s)
Interferón Tipo I/química , Interferón Tipo I/metabolismo , Animales , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacología , Antivirales/química , Antivirales/metabolismo , Antivirales/farmacología , Proliferación Celular/efectos de los fármacos , Chlamydia/efectos de los fármacos , Femenino , Humanos , Inmunidad Mucosa , Interferón Tipo I/farmacología , Ratones , Fosforilación , Conformación Proteica en Hélice alfa , Células RAW 264.7 , Receptores de Interferón/metabolismo , Reproducción , Factor de Transcripción STAT1/metabolismo , Transducción de SeñalRESUMEN
Interferon epsilon (IFNÉ) is a type I IFN that is expressed constitutively in the female reproductive tract (FRT), and contributes to protection in models of sexually transmitted infections. Using multiple cell systems, including reporter cell lines and activated peripheral blood lymphocytes (PBLs), we show that recombinant IFNÉ impairs HIV infection at stage(s) post HIV entry and up to the translation of viral proteins. Consistent with this, IFNÉ upregulated a number of host cell restriction factors that block HIV at these stages of the replication cycle. The potency of IFNÉ induction of these HIV restriction factors was comparable to conventional type I IFNs, namely IFNα and IFNß. IFNÉ also significantly reduced the infectivity of progeny virion particles likely by inducing expression of HIV restriction factors, such as IFITM3, which act at that stage of infection. Thus, our data demonstrate that human IFNÉ suppresses HIV replication at multiple stages of infection.
Asunto(s)
Infecciones por VIH/virología , VIH-1/fisiología , Interferones/metabolismo , Replicación Viral , Células Epiteliales/efectos de los fármacos , Células Epiteliales/patología , Células Epiteliales/virología , Infecciones por VIH/patología , Células HeLa , Humanos , Interferón-alfa/metabolismo , Fitohemaglutininas/farmacología , Linfocitos T/efectos de los fármacos , Linfocitos T/patología , Linfocitos T/virología , Virión/efectos de los fármacos , Virión/metabolismo , Replicación Viral/efectos de los fármacosRESUMEN
The majority of new HIV-1 infections are transmitted sexually by penetrating the mucosal barrier to infect target cells. The development of microbicides to restrain heterosexual HIV-1 transmission in the past two decades has proven to be a challenging endeavor. Therefore, better understanding of the tissue environment in the female reproductive tract may assist in the development of the next generation of microbicides to prevent HIV-1 transmission. In this review, we highlight the important factors involved in the heterosexual transmission of HIV-1, provide an update on microbicides' clinical trials, and discuss how different delivery platforms and local immunity may empower the development of next generation of microbicide to block HIV-1 transmission in the female reproductive tract.