The sequential introduction of HIV-1 subtype B and CRF01AE in Singapore by sexual transmission: accelerated V3 region evolution in a subpopulation of Asian CRF01 viruses.
The rapid spread of the human immunodeficiency virus type 1 (HIV-1) circulating recombinant form (CRF) 01AE throughout Asia demonstrates the dynamic nature of emerging epidemics. To further characterize the dissemination of these strains regionally, we sequenced 58 strains from Singapore and found that subtype B and CRF01 were introduced separately, by homosexual and heterosexual transmission, respectively. Protein similarity scores of the Singapore CRF01, as well as all Asian strains, demonstrated a complex distribution of scores in the V3 loop--some strains had very similar V3 loop sequences, while others were highly divergent. Furthermore, we found a strong correlation between the loss of a V3 glycosylation site and the divergent strains. This suggests that loss of this glycosylation site may make the V3 loop more susceptible to immune surveillance. The identification of a rapidly evolving population of CRF01AE variants should be considered when designing new candidate vaccines and when evaluating breakthrough strains from current vaccine trials.
Kalish
Marcia L
ML
Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. mkalish@cdc.gov
Korber
Bette T
BT
Pillai
Satish
S
Robbins
Kenneth E
KE
Leo
Yee Sin
YS
Saekhou
Ae
A
Verghese
Iris
I
Gerrish
Phillip
P
Goh
Chee Leok
CL
Lupo
Davis
D
Tan
Boon Huan
BH
Brown
Teresa M
TM
Chan
Roy
R
D000163:Acquired Immunodeficiency Syndrome / Q000635:transmission*; D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D005260:Female; D015750:Genes, gag; D014644:Genetic Variation; D006031:Glycosylation; D015699:HIV Envelope Protein gp120 / Q000737:chemistry; D015497:HIV-1 / Q000145:classification* / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010802:Phylogeny; D012725:Sexual Behavior; D012846:Singapore
D015699:HIV Envelope Protein gp120