Molecular Clusters Characteristics And The Mechanism Of Disparate Impact On CD4 Distribution Between Cluster 4 And Cluster 5 In HIV-1 CRF01_AE

Objective:HIV-1 CRF01_AE originated in the central regions of Africa in the 1970 s.Then it gradually spreaded to Thailand and caused an outbreak in the local area.The epidemic of CRF01_AE in China was initiated by multiple phylogenetic clusters introduced into southwest China from Thailand in the 1990 s.Then it rapidly spreaded throughout the country and formed seven CRF01_AE clusters with different geographic distributions and epidemic patterns.In recent years,HIV-1 CRF01_AE has become one of the major epidemic viruses in China,especially in sexually transmitted populations.In addition,CRF01_AE can significantly accelerate the attenuation of CD4+ T cell counts and accelerate disease progression,which has a great challenge to the prevention and control of HIV epidemic in China and also increases the economic burden of disease health.This study aims to describe the prevalence and influencing factors of the strain in the current model by describing the characteristics of the HIV-1 CRF01_AE transmission network.At the same time,we explored the mechanism of CD4 distribution differences among CRF01_AE Cluster 4 and Cluster 5,which are widely prevalent in the MSM population,and provided accurate guideline for HIV prevention and intervention.Methods:1.HIV-1 CRF01_AE molecular cluster: The phylogenetic method was used to determine the subtype/cluster of the strain.Then,through reconstruction the HIV-1 CRF01_AE molecular transmission network,we analyze the optimal gene distance threshold,the factors associated with clustering,epidemic trend of cluster 1,cluster 4,cluster 5,as well as the network parameters,and reveal the epidemic characteristics of HIV-1 CRF01_AE in China.2.The mechanism of disparate impact on CD4+T cell counts between cluster 4 and cluster 5 from the HIV-1 CRF01_AE: We used the National HIV Molecular Epidemiology survey CRF01_AE cluster 4 and cluster 5 dataset for analyzing the difference of CD4 counts at different infection time and the difference X4-using rates.Men who have sex with men seroincidence cohort was used for deep sequencing analysis,virus phenotype identification.Lastly,we compared the genetically and structurally difference to explore the mechanisms that caused disparate impact on CD4 T cell count between clusters 4 and clusters 5 from.Results: 1.HIV Molecular Transmission Network:Under the optimal gene threshold of 0.4%,1214(38.5%)sequences formed 1214 distinct risk transmission clusters,of which cluster 4 and cluster 5 nodes are predominately in this network,especially in the MSM population.Multivariate logistic regression analysis showed that sexual transmission(male),MSM activity,eastern region and cluster 4 can significantly improve the sequences clustered.The analysis of the largest transmission clusters in cluster 1,cluster 4 and cluster 5 shows that the growth of cluster 1 is mainly distributed in the southwestern region,and the cluster4 and cluster5 are mainly distributed in the eastern and northern regions of China.The results of network parameters showed that MSM population,cluster4 and cluster 5 had the highest clustering coefficient values,which indicating that HIV-1 CRF01_AE spreads the fastest in this risk group,and has the greatest impact on the population.2.CD4 distribution differences among Cluster 4 and Cluster 5 in CRF01_AE:Analysis of the newly diagnosed CRF01_AE sample in the 2015 National HIV Molecular Epidemiological Survey,we discovered that people infected by CRF01_AE cluster 4 had significantly lower CD4 counts(391 vs 470,p<0.0001)and higher prevalence of X4-using viruses(17.1 vs 4.4%,p<0.0001)compared with those infected by cluster 5.In an MSM cohort,X4-using viruses were only isolated from seroconvertors in cluster 4,which was associated with low CD4 count within the first year of infection(141 vs 440,p=0.003).Using a coreceptor binding model,we identified unique V3 signatures in cluster 4 that favor X4 ligand use.Conclusion:1.The HIV-1 CRF01_AE molecular transmission network study showed that the cluster 4 and cluster 5 of virus had the fastest spread in the MSM population at the 0.4% gene threshold,which had the greatest impact on the population,and resulting in have highest rates of recent infection in MSM populations.In addition,lead to the clustered rate is significantly higher than other people.2.Study on the phenotypes of clusters 4 and 5 with high rates of infection and high rates of recent infection demonstrated that CRF01_AE clusters 4 evolved with enhanced X4 tropism and viral pathogenesis,while cluster 5 became more attenuated due to a decreased potential of using CXCR4.Therefore,in the future,we should strengthen the monitoring HIV-1 genetic evolved and phenotype shift at the phylogenetic cluster level to control the spread of more pathogenic viruses.