AEGiS-12IAC: The common molecular determinants of HIV-1 tropism for human colonic cells and astrocytes.

12th International AIDS Conference

Geneva, Switzerland - June 28-July 3, 1998

The common molecular determinants of HIV-1 tropism for human colonic cells and astrocytes.

Int Conf AIDS 1998 Jun 28-Jul 3; 12:6 (abstract no. 11118)

Trujillo JR, Meek B, Brain JD
Harvard School of Public Health, Boston, MA, USA.

BACKGROUND: Infection of CD4+ T lymphoyctes by HIV-1 requires the presence of CD4 surface receptor. The specific domains on both gp120 and CD4 that are involved in this envelope-receptor interaction have been well defined. However, HIV-1 infects some cells that do not express CD4, including glial and colonic epithelial cells. Studies in both cells have identified galactosyl ceramide as a potential receptor of HIV-1. However, it appears that the interaction between galactosyl ceramide and gp120 involves multiple sites of the envelope glycoprotein. Recently, we have identified that V3 loop serves as a primary viral determinant for infectivity of CD4-neuronal cells (Trujillo et al, Virology, 217: 613-617, 1996). In addition, preliminary data suggests that some HIV-1 isolates derived from epithelial colonic cells and brains of AIDS patients may have similar V3 loop sequences. The objective of this study is to determine if the same amino acid changes of HIV-1 gp120 V3 loop affect the tropism of CD4-negative human colonic epithelial cells and glial cells.

METHODS: Tumor cell lines glial-U373-MG and epithelial colonic-HT29 were obtained from the American Type Culture collection. SupT1 was obtained from the AIDS Research NIH. In order to study the molecular determinant of gp120 of HIV-1, we first analyzed an HIV-1/IIIb-derived molecular clone, HxB2RU3. Using site directed mutagenesis, we constructed a mutant proviral clone, HxB2RU3CI, which contained the consensus V3 sequence on the background of HxB2RU3. Infection dose was based on quantification of virus by a 50% tissue culture infectious dose.

RESULTS: Our data demonstrates that the amino acid sequence of HxB2RU3 (positive charge residues) is critical for infectivity of these CD4-negative colonic epithelial and glial cells. When the HxB2RU3CI (negative charges residues) was tested, it did not infect the colon or glial cells.

CONCLUSIONS: This data suggest that the V3 loop also serves as a primary viral determinant for infectivity of both colonic and glial CD4-negative cells. Preliminary data suggest that virus derived from colon and brain of AIDS patients present similar V3 sequences. Our findings may have implications in HIV-1 pathogenesis of ADC and HIV-1 wasting syndrome.

Keywords: AEGIS, HIV-1, Antigens, CD4, Tropism, CD4-Positive T-Lymphocytes, Galactosylceramides, Astrocytes, Amino Acid Sequence, HIV-1 Reverse Transcriptase, Colon, Consensus Sequence, Human, immunology, virology, ICA12
980628
11118