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Objective:To investigate the epidemiology, evolution and transmission characteristics of HIV-1 CRF07_BC in Nanjing between 2015 and 2019 to provide scientific basis for precise prevention and control of HIV-1 transmission.Methods:Pol gene sequences of 319 patients with HIV-1 CRF07_BC infection in Nanjing were amplified and sequenced and a maximum likelihood phylogenetic tree was then constructed. Markov Chain Monte Carlo sampling method was used to generate Maximum Clade Credibility Tree. Bayesian Skyline Plot was used to reconstruct the changing trend of the effective population size. Pairwise gene distance method was used to construct molecular network to investigate the transmission features. Results:Among the 319 patients, 303 (95.0%) were male; 264 (82.8%) had multiple sexual partners; only 14 (4.4%) had been using condoms. Most of the infections were occurred in men who have sex with men (MSM), accounting for 77.4%. The maximum likelihood phylogenetic analysis of HIV-1 CRF07_BC revealed two clusters: Cluster1 and Cluster2. Cluster1 mainly contained the strains isolated from MSM and Cluster2 mainly consisted of the strains isolated from heterosexual patients. The most recent common ancestor was 2002.47(1999.91, 2005.43) year for Cluster1 and 1996.38(1992.55, 1999.76) year for Cluster2. The evolutionary rates (95% highest posterior density, 95%HPD) of Cluster1 and Cluster2 were 1.73×10 -3 (1.36×10 -3-2.16×10 -3) substitutions·site -1·year -1 and 2.09×10 -3 (1.50×10 -3 -2.79×10 -3 ) substitutions·site -1·year -1, respectively. The effective population sizes of Cluster1 and Cluster2 tended to be stable after 2002 and 2003, respectively. In addition, Cluster1 and Cluster2 formed eleven and eight unique branches, respectively, suggesting the possibility of divergent epidemics of this genotype. A total of 35 propagation clusters were formed in the molecular propagation network, including 92 Nanjing sequences with an average degree of 4.3. Males, MSM and people with multiple sexual partners were more likely to be connected to the network. Students and young patients were more likely to be connected to the network. Conclusions:HIV-1 CRF07_BC infection was characterized by low age, multiple sexual partners, unprotected behaviors and transmission among MSM in Nanjing from 2015 to 2019. It was recommended to pay more attention to students and young people, to formulate more effective prevention and control measures for high-risk sexual behaviors, and to carry out continuous molecular monitoring of CRF07_BC strain, so as to provide scientific basis for the prevention and control of HIV CRF07_BC.
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Objective To investigate the genetic variations of gag-pol gene in human immunodeficiency virus-1(HIV-1) CRF07_BC strain in Guangdong Province.Methods From February to September in 2015,plasma samples of 78 cases with HIV 1 CRF07_BC infection in Guangdong were collected before antiretroviral treatment.Viral RNA was extracted from plasma.Gene (gag and pol) sequences were amplified by reverse transcriptase and nested-PCR using specific primers.Phylogenetic tree,genic dispersion rate,nucleotide polymorphism,selection pressure and variation characteristics were analyzed.Results The main transmission route of the enrolled patients was homosexual transmission (80.77％,63/78).The gag pol gene phylogenetic tree was divided into two sub-clusters.The strains from different transmission routes were not in cluster.The average genetic dispersion rate and average entropy of gag gene were both higher than those of pol gene.The average genetic dispersion and average entropy of p17 and p6 regions of gag gene were both higher than those of p24.The average genetic dispersion and average entropy of pol gene were higher than those of rt region.The average ds/dn values of gag and pol genes were greater than one.Compared with the common HIV-related antigenic epitopes (A2,A11,B39,B60,Cw1,Cw3,Cw8),the cytotoxic lymphocyte (CTL) epitope mutations in the P17 region were more in the consensus of GAG region than those in the P24 region.The epitope conserved rates were 26.92％,0,1.28％,0,96.15％,82.05％,84.62％ and 98.72％,respectively.The drug resistance rate of pol gene was 2.56％ (2/78).Conclusions The gag and pol genes of CRF07_BC strain in Guangdong are all mutated.Diversity of gag gene is greater than that of pol gene,and gag gene variation is mainly in p17 and p6 regions.gag and pol genes are both affected by negative selection pressure.P17 protein CTL epitope variability is greater than P24 protein epitope.The prevalence of drug resistance mutation is lower than the threshold.It's important to monitor the spread of drug-resistant strains.
ABSTRACT
<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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 CRF01_AE isolates was evaluated in peripheral blood mononuclear cells (PBMCs). The activity against the CRF07_BC and CRF01_AE Env-pseudotyped viruses was analyzed in TZM-bl cells.</p><p><b>RESULTS</b>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 (IC50) 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 IC50s were in the low micromolar range, and NYAD-66 was less effective than NYAD-36 and NYAD-67.</p><p><b>CONCLUSION</b>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.</p>