6th International AIDS Conference


San Francisco, California, USA — June 20-23, 1990

Print this Article


Infection of CD4 negative epithelia in vitro.

Int Conf AIDS 1990 Jun 20-23; 6:337 (abstract no. 1094)
Phillips DM, Bourinbaiar AS; The Population Council, 1230 York Avenue, New York, NY 10021, USA

OBJECTIVE: HIV can be transmitted either by direct exposure to infected blood or through indirect exposure across epithelial barrier as it occurs in cases of milk-borne transmission, intrauterine exposure during pregnancy, and also as result of sexual contact. However, the mechanism of HIV infection through intact epithelia is not well understood.

METHODS: An in vitro model representing exposure to HIV or HIV-infected leukocytes to CD4 negative mucosal epithelium was established. Grown to confluence epithelial cell line (Intestine 407) was exposed for various time periods to HIV infected lymphocytes (MOLT 4) or monocytes (U937) and followed by electron microscopy.

RESULTS: The cell-to-cell contact induced absorptive epithelial cells to uptake HIV via three independent mechanisms: 1) absorptive endocytosis or phagocytosis; 2) direct fusion with target membrane; and 3) endocytosis via coated pits. HIV internalized via endocytic vesicles escapes into cytoplasm of acceptor cell by fusion with endosomal membrane. Occasionally it was observed that HIV directed into lysosomal compartment causes dissolvement of lysosomal membrane and subsequently could be found released into cytosol in form of free coated virions disseminated within acceptor cell.

CONCLUSION: Established model could serve as an illustration of HIV transmission across intact epithelium in case of mother-to-child vertical transmission as well as in case of sexual transmission. Although the exact mechanism responsible for existence of multiple types of HIV entry is not well known, the possibility of simultaneous viral uptake via three different mechanisms by the same CD4-negative epithelial cell indicates on complexity of modes of HIV infection and may have important consequences on the preventive strategies against HIV.

Keywords: AEGIS, Antigens, CD4, HIV, Epithelium, HIV Infections, Infection, Monocytes, HIV Core Protein p24, HIV Envelope Protein gp120, Virion, Lymphocytes, HIV Antibodies, Cell Line, Mucous Membrane, Epithelial Cells, Microscopy, Electron, Endocytosis, Phagocytosis, Child, Human, In Vitro, Female, Pregnancy, complications, immunology, ICA6

900620
1094

Copyright © 1990 - International AIDS Society (IAS). Reproduction of this abstract (other than one copy for personal reference) must be cleared through the IAS.