Genetic characteristics of viral quasispecies of HIV-1 CRF07_BC among intravenous drug users / 病毒学报

To explore the genetic characteristics of viral quasispecies in HIV-1 CRF07_BC infections among intravenous drug users (IDU), the gp120 fragments of HIV-1 env gene were amplified from plasma samples collected from 6 CRF07_BC infected persons using single genome amplification and sequencing (SGA/ SGS) method, and 11 to 28 sequences were obtained from these samples, respectively, A neighbor-joining phylogenetic tree was reconstructed to describe the genetic characteristics of viral quasispecies. The Simplot, segments' phylogenetic trees and diversity plots based on average pairwise distance (APD) were used to identify the recombination events between quasispecies. The SGA sequences derived from single specimen formed a large monophyletic cluster in the neighbor-joining phylogenetic tree and showed the complex topologic structures of viral quasispecies. Of the 6 CRF07_BC infected patients, only one possessed the high genetic homogeneity, whereas the other five individuals showed high heterogeneity, with two to four subclusters inside the monophyletic cluster for each specimen. In addition, the recombinant events were identified among viral quasispecies from 3 cases. The results show SGA technique and phylogenetic analyses are useful tool to investigate the intrahost CRF07_BC gp120 complex quasispecies variation and high genetic diversity.

Distribution of HIV-1 subtypes among different populations in Dehong prefecture, Yunnan province, in 2011 / 中华流行病学杂志

Objective To investigate the distribution of HIV-1 subtypes in Dehong prefecture,Ymnan province,in 2011.Methods 300 HIV-1 positive plasma samples were collected from Jan.2011 to May 2011 in Dehong prefecture.HIV-1 gag genes and env genes were amplified by nestedpolymerase chain reaction (PCR) from viral RNA,After sequencing,the HIV-1 subtypes were determined by phylogenetic analysis.Results Based on the phylogenetic trees of gag gene and env gene fragments,a total of 222 samples were genotyped.Subtype C was the predominant strain in Dehong (43.2％,96/222),followed by unique recombinant forms (URFs,27.0％,60/222),CRF01 _AE ( 21.2％,47/222 ),C R F08_BC ( 5.0％,11/222 ),B,( 2.3％,5/222 ) and CRF07 BC ( 1.4％,3/222).Subtype C strains were predominant in both heterosexually transmitted population and intravenous drug users (IDUs),but different subtype distribution patterns were found in these two populations.All 6 genotypes including subtype C (40.7％,70/172),CRF01_AE (25.0％,43/172),and URFs (25.0％,43/172 ) found in this area among hcterosexually transmitted population,which showed the diversity of genotypes in this population.Except subtype B' and CRF07_BC,the other 3 subtypes and URFs were detected among IDUs,mainly including subtype C (54.8％,23/42) and U R Fs (38.1％,16/42),vhich shoved the concentration trend of genotypes distribution among IDUs.The proportion of URFs increased significantly in this area,including the new BC recombinants (41.7％,25/60) and CRF01_AE relative URFs (58.3％,35/60).However,the distributions of these two URFs among heterosexually transmitted population and IDUs showed no statistical significance.Conclusion The distribution of HIV-1 strains prevailing in Dehong prefecture was diversity,including 5 subtypes and a variety of URFs,of which subtype C was the predominant strain.The distribution patterns of subtype were different among different populations.

Genetic characteristics of HIV-1 CRF01-AE strains in four provinces, southern China / 中华流行病学杂志

Objective To analyze the genetic characteristics of HIV-1 CRF01_AE strains prevailing in. the four provinces of southern China. Methods Plasma samples were collected from the newly diagnosed HIV-1 individuals reported in 2006 in Guangdong, Guangxi, Jiangxi and Hunan province. The gag and env gene fragments were amplified from RNA template extracted from plasma using RT and nested PCR methods. CRF01_AE sequences were analyzed by phylogcnetie methods and characterized by calculating the genetic distance and Entropy analysis. Results Two main epidemic clusters were found to exist in the CRF01 AE strains from 210 HIV-1 CRF01 AE infected individuals collected in the 4 provinces, southern China. It was found that no international reference strain was closely correlated with cluster Ⅰ , which including 123 samples. The strains in cluster Ⅱ, consisting 57 cases of samples, were closely related with the strains identified in Vietnam. Genetic distance analysis of gag and env genes showed that the diversity of cluster Ⅰ was obviously less than that of cluster Ⅱ. Data on nucleotide polymorphism showed that nucleotides compositions of 42 sites in gag and 40 sites in env wer esignificantly different between the two clusters. When compared with cluster Ⅱ , the polymorphism decreased at 61 nucleotide sites but increased at 21 sites in cluster Ⅰ. Conclusion This was the first report describing that two main epidemic clusters were existed in CRF01_AE strains prevailing in the 4 provinces, Southern China. The vires in cluster Ⅰ was the dominant strain in this region, with shorter period of circulation and higher proportion seen in the HIV-infected population, which might belong to CRF01_AE strain with certain features facilitating the spread of the virus. The virus in cluster Ⅱ was highly homology with the CRF01_AE strains from Vietnam, and seemed to have had several events of epidemics in populations in border regions of China and Vietnam.