V3 loop sequence analysis of seven HIV type 1 group O isolates phenotyped in peripheral blood mononuclear cells and MT-2 cells.
HIV-1-infected individuals from which syncytium-inducing (SI) viruses are isolated most often progress more rapidly to AIDS than individuals carrying only non-syncytium-inducing (NSI) viruses. The syncytium-inducing capacity of virus isolates is commonly determined in conjunction to replication in MT-2 cells. Comparison of HIV-1 env sequences and a site-directed mutagenesis study have indicated that the presence of a positively charged amino acid at position 11 or 25 in the V3 loop is minimally required for the SI capacity of HIV-1 subtype B viruses. Studies have also shown a similar correlation between positively charged signature amino acids in the V3 loop and syncytium formation in MT-2 cells for HIV-1 subtypes A, D, and E. In the present study virus phenotype was determined and compared to the V3 loop sequence of seven HIV-1 group O isolates. Three of the HIV-1 group O isolates showed the NSI/non-MT-2 tropic phenotype and two showed the SI/MT-2 tropic phenotype, whereas two isolates presented an uncommon NSI/MT-2 tropic phenotype. The V3 loop of the two SI/MT-2 tropic isolates had a high net positive charge and contained a positively charged amino acid at position 11 or 25. The V3 loop of the two NSI/MT-2 tropic isolates had a low net positive charge and contained a single positively charged amino acid at position 37.
De Jong
J
J
Department of Human Retrovirology, Academic Medical Centre, Amsterdam, The Netherlands.
Simon
F
F
Van der Groen
G
G
Baan
E
E
Saragosti
S
S
Brun-Vézinet
F
F
Goudsmit
J
J
D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D005260:Female; D015726:Giant Cells / Q000821:virology; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000235:genetics*; D015497:HIV-1 / Q000737:chemistry / Q000145:classification* / Q000235:genetics; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000821:virology*; D008297:Male; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics*; D010641:Phenotype; D017386:Sequence Homology, Amino Acid; D013601:T-Lymphocytes / Q000821:virology*
D015699:HIV Envelope Protein gp120; C059762:HIV envelope protein gp120 (305-321); D010446:Peptide Fragments