Antiviral Activity of Dual-acting Hydrocarbon-stapled Peptides against HIV-1 Predominantly Circulating in China

Objective New rationally designed i,i＋7-hydrocarbon-stapled peptides that target both HIV-1 assembly and entry have been shown to have antiviral activity against HIV-1 subtypes circulating in Europe and North America. Here, we aimed to evaluate the antiviral activity of these peptides against HIV-1 subtypes predominantly circulating in China. Methods The antiviral activity of three i,i＋7-hydrocarbon-stapled peptides, NYAD-36, NYAD-67, and NYAD-66, against primary HIV-1 CRF07_BC and CRFOI_AE isolates was evaluated in peripheral blood mononuclear cells （PI3MCs）. The activity against the CRF07_BC and CRF01_AE Env-pseudotyped viruses was analyzed in TZM-bl cells. Results We found that all the stapled peptides were effective in inhibiting infection by all the primary HIV-1 isolates tested, with 50% inhibitory concentration toward viral replication （ICso） in the low micromolar range. NYAD-36 and NYAD-67 showed better antiviral activity than NYAD-66 did. We further evaluated the sensitivity of CRF01_AE and CRF07_BC Env-pseudotyped viruses to these stapled peptides in a single-cycle virus infectivity assay. As observed with the primary isolates, the ICs0s were in the low micromolar range, and NYAD-66 was less effective than NYAD-36 and NYAD-67. Conclusion Hydrocarbon-stapled peptides appear to have broad antiviral activity against the predominant HIV-1 viruses in China. This finding may provide the impetus to the rational design of peptides for future antiviral therapy.

Encapsidating artificial human papillomavirus-16 mE7 protein in human papillomavirus-6b L1/L2 virus like particles

Background Human papillomaviruses （HPVs） can infect squamous or mucosal epithelia and cause cervical cancer or genital warts. Coinfection with multiple HPV types is a common finding of many epidemiological studies. Therefore, it is necessary to develop a vaccine, which can eradicate established HPV infections and prevent other HPV infections. In this study, we generated chimeric virus like particles （cVLPs） composed of HPV-6b L1, HPV-6b L2 and one artificial HPV-16 mE7 proteins. Methods The artificial HPV-16 mE7 gene was designed by codon modification, point mutation and gene shuffling then chemically synthesized and subcloned behind HPV-6b L2. HPV-6b L1 and L2-mE7 were expressed in insect cells by using Bac-to-Bac system. The generated cVLPs were purified by CsCI gradient ultracentrifuge and analyzed by immunoblot, electron microscope and haemagglutination assay. Results The HPV-6b L1 and L2-mE7 proteins were well expressed in insect cells and could selfassemble into cVLPs, whose diameter was about 55 nm and similar to that of HPV-6b L1/L2 VLPs. Intact cVLPs could be recognized by H6.M48 neutralizing monoclonal antibody and HPV-6b L2 polyclonal antibody, while the denatured cVLPs, but not the intact cVLPs, were reactive to HPV-16 E7 polyclonal antibody. HPV-6b LI/L2-mE7 cVLPs haemaggiutinated mouse erythrocytes as efficiently as HPV-6b L1/L2 VLPs did. Conclusions The insertion of the 158 amino acid HPV-16 mE7 protein behind L2 did not disrupt the correct assembling of cVLPs. The morphological characteristics and haemagglutinating activity of cVLPs were similar to those of HPV-6b LI/L2 VLPs. The cVLPs retained conformational B cell epitopes of HPV-6 VLPs and HPV-16 mE7 protein had an internal location in the cVLPs. Therefore, large modified E7 protein with higher immunogenicity could be incorporated into cVLPs by fusing to the C-terminus of L2, which would help to improve the therapeutic effects of LI/L2-E7 cVLPs.