6th International AIDS Conference


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

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The human env-like protein is an MHC class I molecule.

Int Conf AIDS 1990 Jun 20-23; 6:337 (abstract no. 1093)
Siccardi AG, Grassi F, Lanza P, De Santis C, Pelagi M, Beretta A; Dipartimento di Biologia e Genetica per le Scienze mediche, Universita di Milano, Italy

OBJECTIVE: To determine the relevance of the human env-like protein (HELP) in HIV infection. HELP is a 45kDa activation protein of monocytes and lymphocytes defined by two monoclonal antibodies (M38 and L31) obtained from a mouse immunized with HIV. M38 (but not L31) immunoprecipitates HIV 1 gp120, inhibits macrophage antigen presentation and inhibits syncytium formation between the cell lines 8E51(HIV 1) and MOLT-3. L31 is more affine for HELP and inhibits T4 cell proliferation after mitogenic stimuli.

METHODS: Affinity purification on solid-phase monoclonal antibodies, radioimmunoprecipitation, Western blotting.

RESULTS: Solid-phase M38 coprecipitates beta2-microglobulin, and anti-beta2 coprecipitates HELP. Conversely, L31 does not coprecipitate beta2-microglobulin (its binding probably dissociates the bimolecular complex). Moreover, affinity purified HELP is reactive with monoclonal antibodies which recognize monomorphic determinants of HLA A,B,C.

CONCLUSION: The finding that HELP is a class I molecule could explain why it is present in the virions of HIV 1, HIV 2 and HTLV-I and, possibly, the frequent occurrence of anti HELP antibodies in patients' sera. However, the tissue distribution of HELP is highly restricted (activated monocytes and lymphocytes and endothelial cells) and does not correspond to the distribution of classical HLA molecules.

Keywords: AEGIS, Gene Products, env, Major Histocompatibility Complex, HIV-1, Antibodies, Monoclonal, HIV Antibodies, HLA Antigens, Antibodies, Anti-Idiotypic, HIV, Myosin Heavy Chains, Human T-lymphotropic virus 1, Lymphocytes, Blotting, Western, HIV-2, Monocytes, Human, Animal, Mice, immunology, genetics, ICA6

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