Replication capacities of chimeric NL4-3 encoding gag-protease from recent HIV-1 isolates are significantly reduced compared to those derived from isolates in early days of epidemic in Japan Shigeru Nomura, Noriaki Hosoya, Tadashi Kikuchi, Michiko Koga, Hitomi Nakamura, Tomohiko Koibuchi, Takeshi Fujii, Ai Kawana-Tachikawa, Aikichi Iwamoto, Toshiyuki Miura The Institute of Medical Science The University of Tokyo

Backgrounds HIV-1 evolves rapidly, escaping from host selection pressures like CTL response Some CTL escape variants with reduced replication capacities could transmit from one person to another Escape variants accumulate in a population and could replace previously dominant forms Recent isolates may have distinct replication capacity from those from early days of HIV epidemic Objectives To investigate if HIV-1 replication capacity has been changed over the epidemic in Japan

Studied Population 158 treatment naïve Japanese with asymptomatic chronic HIV-1 infection Research Hospital of the University of Tokyo from 1994 to 2009 Sexual Intercourse (85% were MSM) Plasma from near first visit Limited to cladeB infection

Generation of chimeric viruses by homologous recombination RT-PCR plasma virus Slope of GFP expression gag- pro LTR-driven GFP reporter T cell line ⊿ gag-pro pNL4-3 gag- pro infection Measure % of GFP expression Methods Sequencing and subtyping

No correlation between pVL, CD4+ T cell count and first visit year r=0.035 p=0.33 r=0.040 p=0.70 pVLCD4

JP US CN NL4-3 N = 55 within a cluster in the phylogenetic tree rp value year ** CD4-2.0e log pVL ** r = p = ** CD4 T cell counts > 200 /  l, n = 145 (n=22) CD4 >500/μlCD4 >300/μl (n=101) stratified by CD4+ T cell count Correlation between VRC and first visit year

Conclusions and Limitations Recent HIV-1 circulating in Japan may have reduced In vitro replication capacity Investigation was limited to Gag-protease Backbone of chimeric viruses: –NL4-3 is an early laboratory strain 15 years may be too short