T-tropic sequence of the V3 loop is critical for HIV-1 infection of CXCR4-positive colonic HT-29 epithelial cells.
Some colonic and neuronal cells which are CD4- but galactosyl ceramide-positive are susceptible to infection with HIV-1. We have previously shown that the T-cell tropic V3 loop of HIV-1 gp120 serves as a primary viral determinant for infectivity of CD4- neuronal cells. However, the nature of the V3 loop of HIV-1 needed for infection and the V3 loop's interaction with coreceptors on colonic epithelial cells have not been fully analyzed. By using HIV-1 molecular clones, we show that the T-cell tropic V3 domain is critical for HIV-1 infection of colonic HT-29 epithelial cells. Because T-cell tropic HIV-1 can use CXCR4 as a coreceptor in T cells, we set out to determine the role of CXCR4 during infection of HT-29 cells. Using reverse transcriptase-polymerase chain reaction (RT-PCR) and immunostaining, we show that these epithelial cells of colonic origin express the chemokine receptor CXCR4. Importantly, antibody against CXCR4 or a neutralizing antibody against HIV-1 gp120 V3 loop blocks T-cell tropic HIV-1 entry into HT-29 cells. These data indicate that the V3 loop of HIV-1 and the chemokine receptor CXCR4 are both critical for HIV-1 infection of colonic HT-29 epithelial cells. An HIV-1 T-tropic virus may be responsible for the infection of human colonic epithelial cells in vivo.
Trujillo
J R
JR
Physiology Program, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA. jtrujill@hsph.harvard.edu
Goletiani
N V
NV
Bosch
I
I
Kendrick
C
C
Rogers
R A
RA
Trujillo
E B
EB
Essex
M
M
Brain
J D
JD
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D003001:Cloning, Molecular; D016384:Consensus Sequence; D005814:Genes, Viral; D015699:HIV Envelope Protein gp120 / Q000235:genetics* / Q000378:metabolism; D015497:HIV-1 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D019073:HT29 Cells; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D017354:Point Mutation; D019718:Receptors, CXCR4 / Q000032:analysis* / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000821:virology*
D000911:Antibodies, Monoclonal; D015699:HIV Envelope Protein gp120; D019718:Receptors, CXCR4