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=0.035p=0.33

r=0.040p=0.70

pVL CD4

JPUSCN

NL4-3

N = 55

within a cluster in the phylogenetic tree

r p valueyear -0.0066 0.0012**CD4 -2.0e-5 0.72log pVL 0.026 0.0097**

<Multivariate analysis>

r = -0.0069p = 0.00028**

CD4 T cell counts > 200 /ml, 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