HIV-1Subtypes.Diversity And Drug-resistang Nutations In Guangxi Province

AIDS,which is called Acquired Immunodeficiency Syndrome,is a kind of immunodeficiency disease, Human Immunodeficiency Virus(HIV)is the pathogen of AIDS. Infected patients will die of opportunity infection and cancer.Human immunodefiency virus type1(HIV-1) infection has continued to be a global epidemic problem since its discovery in the early1980s.According to the2009data shows there have been65million patients with HIV-1infection, there were25million HIV-1infected patients who died of AIDS. HIV-1prevalence in China has also been growing in recent years. According to UNAIDS and WHO statistics that about780000people are chronically infected with HIV/PLHIV at the end of2011. Guangxi Province,because of its special geological position which experienced one of earliest and heaviest epidemics of HIV in China.So it is important to prevent and treat HIV infection effectively. To characterize the subtypes of HIV-1among injecting drug users (IDU) in Guangxi, where a phase â…¡ HIV vaccine trial is ongoing. A total of67HIV-1positive samples were collected from consenting IDUs in2008-2010. HIV-1Gag/Pol and Env sequences were amplified and sequenced. Phylogenetic and sequence diversity analyses were performed. Unique drug-resistant mutations were also detected. Part â… The prevalence of HIV-1subtypes in Gangxi provinceTo characterize current HIV-1prevalence,67HIV-1sero-positive blood samples were collected consenting IDUs from Baise, Nanning,Beihai between2008to2010. DNA alignment was performed by the Clustal W method under MEGA5, followed by manual adjustment. Reference sequences were retrieved from the Los Alamos National Laboratory HIV Sequence Database (http://www.hiv.lanl.gov). Phylogenetic analysis was also conducted with MEGA5. Neighbor-joining trees were constructed using a Kimura2-parameter model and tested by the bootstrap method for1,000replicates.In total,67partial Gag/Pol gene sequences were retrieved from antiviral-naive HIV-1positive IDU patients in Beihai, Baise, and Nanning cities. Phylogenetic analyses showed various subtypes among the25samples from Beihai city, including14CRF08_BC (56%), nine CRF01_AE (36%), and two CRF07_BC (8%). Of the21sequences in Nanning,16(76.19%) were determined to be CRF08_BC (the local dominant subtype), while three (14.28%) were CRF01_AE and the rest (9.52%) CRF07_BC. In contrast, all21samples from Baise were classified as CRF08_BC, showing a complete dominance within the area.CRF07_BC Gag sequences we detected contain a unique in-frame deletion in the p6domain that is absent from the CRF08_BC and CRF01_AE Gag sequences.Baise city is very close to Yunnan province, a location that may have given rise to CRF08_BC. The dominance of CRF08_BC that we observed in Baise confirmed the transmission route of HIV-1from Yunnan to Guangxi. Different patterns were observed for various HIV-1subtypes being transmitted in different areas within Guangxi province. The decrease in the CRF08_BC ratio from western to southern Guangxi, together with the increase in CRF01_AE one, may indicate two opposite transmission routes of the two HIV subtypes. Part â…¡Amino Acid Analysis of C2V4EnvelopeThe alignment of all the CRF08_BC sequences (determined by the Gag/Pol sequences) revealed a highly conserved V3loop and a highly variable V4loop in the partial Env fragment, which is consistent with previous studies. A conserved dodecapeptide, RIGPGQTFYATG, was found in20of24BC sequences, with the four exceptions being BS079, NN002, BH074, and NN025; the last two sequences contained an undetermined amino acid "X" and may in fact be identical. No similar fragment was observed in the V4loops, which varied in both their sequence and residue length However, when they were compared to the protein alignment of the same region in32samples retrieved in2000, we observed a much higher degree of variation among the entire C2-V4region, except for the C2region. The average number of different amino acid in this C2-V4region of our2008-2010strains was24(range,5to36) from97CNGX₇F, while only11amino acid residues were different on average (range,5to17) for the32old strains from2000. The CRF08_BC envelope sequences from Guangxi were previously determined to be of Indian origin However, different evolutionary patterns with a generally lower residue frequency were observed for these Env fragments at following residues associated with Indian type C.Notably,335K was the only position that showed more consistency with the Indian type C origin.Part â…¢Drug resistant mutations of HIV-1Drug resistant of HIV-1is one of the conditionality factors in antiretroviral therapy, mainly caused by codon mutation in the course of virus replication. Our experiment research the prevalence of HIV-1drug resistance, each sequence was submitted to the HIV Drug Resistance Database at Stanford Umversity. All CRF08_BC sequences from all three cities showed a T69S mutation in then RT region. A major resistance mutation in PR, M46I, was detected in sample BS118against protease inhibitor. This same mutation was also detected in NN128. a CRF07_BC strain. Providing resistance to atazanavir, fosamprenavir, indinavir, lopinavir, and nelfinavir, this M46I mutation indicated the occurrence of a low-level transmission of PI-resistant HIV-1strain(s) in Baise city. K101Q was detected as an NNRTI-resistant mutation in NN019, reducing the virus's susceptibility to nevirapine, efavirenz, and etravirine.While most drug-resistant mutations were found in the CRF08_BC sequences, an L1061was observed in the RT region of BH045and BH053, two of the CRF01_AE sequences discovered in Beihai city. Along with K103R, detected in the same region of unclassified BH074, the impact of these two mutations was not clear, since L1061is a very common polymorphism for HIV-1sequences, and K103R appears in1-2%untreated persons,also, both of these mutations decrease NNRTI susceptibility only when paired with an additional mutation of V179D, which our sequence did not cover. In addition, a minor PI-resistance mutation, L101, was found in BH045and NN020; this mutation is associated with resistance to most PIs when it is present with other mutations, and it can also be detected in5-10%of untreated patients. While most of the mutations caused only minor drug resistance, the NRTI-resistant mutation K65R was also discovered in NN137, one of the CRF01_AE strains. K65R introduces intermediate resistance to didanosine, abacavir, lamivudine, emtricitabine, and tenofovir, and it also causes low-level resistance to stavudine and hypersusceptibility to zidovudine.