Screening Analysis Of HIV-1 Broadly Neutralizing Antibodies From Men Who Have Sex With Men In Shenzhen

Background: Human immunodeficiency virus（HIV）is the leading cause of acquired immune deficiency syndrome（AIDS）.The virus spreads rapidly all over the world since it was found in the 1980 s.In recent years,there are obviously rising trends of newly detected cases in our country,especially the group of men who has sex with men（MSM）,the abnormal rapid growth of the epidemic caused widespread concern.Neutralizing antibodies is the main immune response to HIV infection.The foundation and key links of effective vaccine design and development is to induce the human body to produce broadly neutralizing antibodies（bNAbs）,which has the ability to neutralize different strains.Recent studies have shown that,related antibodies,drug research and application are facing major challenges due to the ongoing restructuring of evolution and diffusion of HIV-1 epidemic strains in MSM population in China.Objective: Shenzhen,as one of the largest port cities and the main gathering area of the MSM in China,it’s particularly urgent to establish a detection platform of HIV-1 bNAbs for the analysis of local strain evolution and the possibility effect on bNAbs.Meanwhile it’s also lay the foundation for research on the mechanism and application of bNAbs.Methods: The first part is to establish a detection platform of HIV-1 bNAbs.Firstly we cultivate HIV-env plasmids（which contain standard HIV-env sequences）and the backbone（which contain whole HIV-1 sequences except env sequences）plasmids.Then we do sequencing,restriction enzyme digestion of these plasmids.After that we take two plasmids together co-transfect into 293 T cells to obtain pseudovirus,and titrate pseudovirus with TZM-bl cells.Use Graphpad Prizm 5.0 to calculate the half of tissue culture infectious dose（ID50）.The second part is detection and application of the platform.Including set up a small formation of MSM,follow up regularly,retention samples and sequencing analysis the population prevalence of HIV-1 subtype among the infected people in Shenzhen area;using this platform to screen the subtypes of bNAbs,types of neutralizing antibodies from these people,while testing the feasibility of the platform;and antibody competition experiments to preliminary analysis the binding sites of the representative blood sample which has a certain ability of broadly neutralizing.Results: In recent years,the proportion of HIV-1 subtype CRF07_BC（43.4%）and CRF55₀1B（15.4%）which is prevalent in MSM increase rapidly.Take 88 samples from 34 CRF07_BC infected people to neutralizing antibodies detection,there are 10 samples with broadly neutralizing been screened out（ID50 Titer≧25）,2 of them shows better width of neutralizing and can response to 7（58.3%）kinds pseudovirus of inside 12.All those binding mechanism are not targeting to gp120 after preliminary analysis.Conclusions: These results suggest that the evolution of HIV-1 strain and its prevalent trend in Shenzhen MSM population is increasingly complex,it’s necessary to enhance related research especially the recombinant subtype which increase rapidly.We have already set up a small MSM cohort and establish a detection platform through TZM-bl cells,moreover it has been applied in practice.The preliminary screening results comes to that there are bNAbs inside the patient’s serum which has neutralization activity.