Inhibition of human immunodeficiency virus infection in human colon epithelial cells by recombinant interferon‐γ

Abstract

Pretreatment of human colon epithelial cells HT29 by recombinant gamma interferon (IFN)-gamma was found to protect the cells from infection with various isolates of human immunodeficiency virus (HIV)-1 and HIV-2, as assessed by co-cultivation with human T lymphoblastoid cells and gene amplification by polymerase chain reaction technique. Additionally, IFN-gamma induced a dose-dependent inhibition of HIV-1 and HIV-2 production in chronically infected HT29 cells. In situ hybridization studies demonstrated that IFN-treated cells were still able to synthesize viral messenger ribonucleic acid. However, the expression of the p24 product of the gag gene was markedly decreased after IFN treatment as demonstrated by radio-immunoprecipitation assay. Taken together, these data suggested that the cytokine acted at the post-translational level by inhibiting the processing of structural viral proteins. It is concluded from this study that IFN-gamma has a potent anti-HIV effect on epithelial gastrointestinal cells.

Synthetic Soluble Analogs of Galactosylceramide (GalCer) Bind to the V3 Domain of HIV-1 gp120 and Inhibit HIV-1-induced Fusion and Entry

“…The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 synthesized according to Tam (21) purified to homogeneity, and the amino acid analysis of the purified peptide agreed with the deduced amino acid ratios. The other peptides used in this study were obtained as described previously (22).…”

“…The rationale for this strategy was based on previous observations suggesting that the GalCer receptor, putatively used by HIV-1 to infect neural cells (16,17) and colon cells (18,19), was recognized by the V3 domain of gp120: (i) anti-V3 antibodies block gp120 binding to GalCer (26); (ii) these antibodies inhibit HIV-1 infection of CD4 Ϫ /GalCer ϩ human colon epithelial HT-29 cells (15,26); (iii) synthetic multimeric peptide constructs of the V3 consensus sequence (GPGRAF) bind to GalCer and prevent HIV-1 entry into HT-29 cells (24); (iv) the V3 loop is a common genetic determinant controlling HIV-1 tropism for neural SKNMC cells (17,28) and HT-29 cells (29), as demonstrated by using chimeric proviral clones. Although these data strongly suggested the involvement of the V3 loop in GalCer recognition, direct evidences for a physical interaction between GalCer and the V3 loop of gp120 were lacking.…”

“…The indicated amounts of lipids were then resuspended in chloroform/ethanol (1:20, v/v) and allowed to adsorb on Immulon 1 multiwell plates by evaporation of the solvent under a chemical hood. After saturation of the plates with PBS, containing 2% bovine serum albumin (1 h at 37°C), the lipids were probed with the anti-GalCer R-mAb (18) and processed for ELISA as described above.…”

“…An antigen capture assay (DuPont, Les Ulis, France) was used for p24 determinations. The viruses used in these experiments were the prototype HIV-1(LAI) or the african HIV-1(NDK) isolates, as described previously (18,19,22,24).…”

Transepithelial transport of HIV-1 by M cells is receptor-mediated

“…The glycosphingolipid galactosylceramide (GalCer or lactosyl cerebroside) that binds with highaffinity gp120 has been proposed to act as a CD4 surrogate HIV-1 receptor on various epithelial cell lines (13). On the basis of their cellular tropism, replication kinetics and ability to induce syncytia formation on infection, HIV-1 strains have been grouped into two categories, the nonsyncytium-inducing͞monotropic or R5 strain and the syncytium-inducing͞lymphotropic or X4 strain (14,15).…”