Abstract
The ultrastructural alterations induced by human immunodeficiency virus type 1 (HIV-1) in the human colon epithelial cell line HT-29 infected in vitro have been evaluated. These cells express high levels of galactosyl ceramide (GalCer), an alternative receptor for HIV-1 surface envelope glycoprotein gp120. Using immunolabelling for electron microscopy and immunofluorescence techniques, we detected the GalCer receptor in both the apical and basolateral membranes of differentiated HT-29 subclones. This nonpolar distribution is consistent with our previous observation that HIV infects both the apical and basolateral surfaces of epithelial cells in vitro. A transmission electron microscopy study demonstrated two major ultrastructural perturbations in the HIV-producing cells: (i) an unusual number of secretory granules; and (ii) the appearance of intracellular lumina with disorganized microvilli, indicating a defect in striated border assembly and differentiation. In addition to these morphological alterations, our study revealed the presence of fat vacuoles, concentric membranous bodies, tubuloreticular inclusions and giant mitochondria in the cytoplasm of HIV-infected cells. Taken together, these abnormalities could account for HIV-induced enteropathy, consisting of chronic diarrhea and malabsorption in the absence of enteric pathogens.
Published Version
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