451. Expression of GBV-C E2 Protein Motifs in a CD4+ T Cell Line (Jurkat) Inhibits HIV-1 Entry and Replication
Session: Poster Abstract Session: HIV Pathogenesis and Immunity
Friday, October 21, 2011
Room: Poster Hall B1
Background: Persistent GB virus C (GBV-C) viremia is associated with prolonged survival in HIV-infected cohorts, and GBV-C inhibits HIV replication in vitro. Jung et al. found that addition of recombinant E2 protein to cells inhibits HIV-1 entry at the fusion step, and that expression of E2 in CD4+ cells renders them highly resistant to HIV infection. In this study, we expressed a series of recombinant E2 protein deletion mutants to further characterize the E2 protein domain required for HIV inhibition.

Methods: Jurkat cell lines were stably transfected with plasmids containing GBV-C E2 sequences followed by an EMC IRES directing GFP expression. Cells expressing E2 peptides including the entire protein except for the C-terminal transmembrane domain, and a series of N- and C-terminal deletions were prepared. Control cell lines were also generated that expressed GFP only (vector control: VC), or GBV-C RNA that encodes E2 with a frameshift introduced so that no protein was expressed (FS).

Results: HIV replication was inhibited in all cell lines expressing a GBV-C E2 region of 17 amino acids, but not in the E2 expressing cell lines without this motif. VC and FS cells did not inhibit HIV, nor did cells expressing the 17 E2 amino acids in a scrambled order (Scr). All HIV isolates studied (representing 3 Clades) were inhibited. HIVenv but not VSVG pseudotyped retroviruses were inhibited, thus inhibition occurred during virus entry. Addition of recombinant E2, but not a synthetic 17mer peptide to cells inhibited HIV-1. CD4 and CXCR4 were not decreased on the Jurkat cells, thus the effect was not due to altered HIV co-receptor expression.

Conclusion: Expression of recombinant GBV-C E2 protein in a CD4+ cell line renders the cells less permissive or totally resistant to HIV-1 infection, and inhibition occurs at the entry step.  Only 17 amino acids of E2 are required for inhibition, and protein expression is required as the FS cell line did not inhibit HIV-1. Addition of a synthetic 17mer E2 peptide to cells was not inhibitory, suggesting that the peptide must enter the cell for an inhibitory effect. Studies to assess this using a Tat-protein-transduction-fused 17mer peptide are underway. These studies identify a novel and potential anti-HIV small molecule therapy.


Subject Category: H. HIV/AIDS and other retroviruses

Jinhua Xiang, MD, James McLinden, PhD, Thomas M Kaufman, B.S., Qing Chang, B.S., Emma Mohr, B.S. and Jack T. Stapleton, MD, University of Iowa and Iowa City VAMC, Iowa City, IA

Disclosures:

J. Xiang, None

J. McLinden, None

T. M. Kaufman, None

Q. Chang, None

E. Mohr, None

J. T. Stapleton, None

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