Development of an HIV-1 Subtype Panel in China: Isolation and Characterization of 30 HIV-1 Primary Strains Circulating in China

Abstract

BackgroundThe complex epidemic and significant diversity of HIV-1 strains in China pose serious challenges for surveillance and diagnostic assays, vaccine development and clinical management. There is a lack of HIV-1 isolates in current canonical HIV-1 subtype panels that can represent HIV-1 diversity in China; an HIV-1 subtype panel for China is urgently needed.MethodsBlood samples were collected from HIV-1 infected patients participating in the drug-resistance surveillance program in China. The samples were isolated, cultured and stored as neat culture supernatant. The HIV-1 isolates were fully characterized. The panel was used to compare 2 viral load assays and 2 p24 assays as the examples of how this panel could be used.ResultsAn HIV-1 subtype panel for China composed of 30 HIV-1 primary strains of four subtypes (B [including Thai-B], CRF01_AE, CRF07_BC and G) was established. The samples were isolated and cultured to a high-titer (106-109 copies/ml)/high-volume (40ml). The HIV-1 isolates were fully characterized by the final viral load, p24 concentration, gag-pol and envC2V3 sequencing, co-receptor prediction, determination of the four amino acids at the tip of the env V3-loop, glycosylation sites in the V3 loop and the drug-resistance mutations. The comparison of two p24 assays and two viral load assays on the isolates illustrated how this panel may be used for the evaluation of diagnostic assay performance. The Pearson value between p24 assays were 0.938. The viral load results showed excellent concordance and agreement for samples of Thai-B, but lower correlations for samples of CRF01_AE.ConclusionThe current panel of 30 HIV-1 isolates served as a basis for the development of a comprehensive panel of fully characterized viral isolates, which could reflect the current dynamic and complex HIV-1 epidemic in China. This panel will be available to support HIV-1 research, assay evaluation, vaccine and drug development.

Overview of HIV molecular epidemiology among people who inject drugs in Europe and Asia

“…Major strains circulating in China include subtype B’ (9.6%), CRF01_AE (27.6%), CRF07_BC (35.5%), and CRF08_BC (20.1%) (Han et al, 2015; He et al, 2012; Laeyendecker et al, 2005). Subtype C is currently a minor clade with a prevalence at 1.6% (He et al, 2012).…”

“…The province of Yunnan that is located in the Southwest part of China and shares borders with Vietnam, Laos, and Burma (Myanmar), has played an important role in HIV spread in China and serves as a hotspot of genetic mixing due to its closeness to the Golden Triangle and the heroin trafficking routes (Beyrer et al, 2000). Subtype C from India and subtype B from Thailand caused the first outbreaks among PWID in Yunnan in the late 1980s and early 1990s (Han et al, 2015; Piyasirisilp et al, 2000; Tee et al, 2008; Zheng et al, 1994). Subtype B', that soon became the predominant B clade in China (Graf et al, 1998; Lau et al, 2007), and subtype C recombined to generate two related but distinct strains, CRF07_BC and CRF08_BC, which trace their origin to Yunnan and fueled the epidemic among PWID in Northwestern, Southeastern and Northeastern China, and to Taiwan (CRF07_BC) (Han et al, 2015; He et al, 2012; Laeyendecker et al, 2005; Lau et al, 2007; Li et al, 2015; Lin et al, 2006; Piyasirisilp et al, 2000; Takebe et al, 2010; Tee et al, 2008).…”

“…Subtype C from India and subtype B from Thailand caused the first outbreaks among PWID in Yunnan in the late 1980s and early 1990s (Han et al, 2015; Piyasirisilp et al, 2000; Tee et al, 2008; Zheng et al, 1994). Subtype B', that soon became the predominant B clade in China (Graf et al, 1998; Lau et al, 2007), and subtype C recombined to generate two related but distinct strains, CRF07_BC and CRF08_BC, which trace their origin to Yunnan and fueled the epidemic among PWID in Northwestern, Southeastern and Northeastern China, and to Taiwan (CRF07_BC) (Han et al, 2015; He et al, 2012; Laeyendecker et al, 2005; Lau et al, 2007; Li et al, 2015; Lin et al, 2006; Piyasirisilp et al, 2000; Takebe et al, 2010; Tee et al, 2008). CRF07_BC has also become the predominant strain among PWID (>80%) in Taiwan (Chen et al, 2012, 2010; Huang et al, 2014; Lin et al, 2006).…”