       Document 0248
 DOCN  M95A0248
 TI    Unidirectional budding of HIV-1 at the site of cell-to-cell contact is
       associated with co-polarization of intercellular adhesion molecules and
       HIV-1 viral matrix protein.
 DT    9510
 AU    Fais S; Capobianchi MR; Abbate I; Castilletti C; Gentile M; Fei PC;
       Ameglio F; Dianzani F; Institute of Virology, La Sapienza University,
       Rome, Italy.
 SO    AIDS. 1995 Apr;9(4):329-35. Unique Identifier : AIDSLINE MED/95314787
 AB    OBJECTIVES: To explore the possibility that HIV-1 budding and cellular
       adhesion molecules co-polarize at cell-to-cell contact sites. To
       investigate the incorporation of host-cell-derived adhesion molecules
       into HIV-1. METHODS: The cellular sites involved in HIV-1 budding were
       examined by transmission electron microscopy. Single and double
       immunocytochemistry staining was used to evaluate the cellular
       distribution of the viral matrix protein and adhesion molecules.
       Quantitative flow cytometry was used to measure the cellular expression
       of adhesion molecules. An immunocapture technique was used to measure
       the presence of cell-derived proteins on HIV-1. The captured virus was
       measured by a p24 antigen assay. The infectivity of virus captured by
       monoclonal antibodies was tested by measuring the virus antigen yield in
       supernatants after the addition of sensitive cells. RESULTS: Released
       and budding HIV-1 was mainly localized at the cell-to-cell contact
       regions. This feature was consistent with a polarized staining for the
       virus matrix protein p18 at cell-to-cell contact regions. Intercellular
       adhesion molecules (ICAM)-1 in HIV-1-infected cells were polarized on
       both isolated cells and syncytia, co-localizing with HIV-1 matrix
       protein. HIV-1 incorporated all the adhesion molecules expressed by the
       host cells, although without quantitative correlation with their
       cellular expression. CONCLUSIONS: HIV-1 is released at cell-to-cell
       membrane contact sites. Both ICAM-1 and virus matrix protein
       co-polarized on isolated cells and syncytia at the sites involved in the
       recruitment of uninfected cells. The impressive concentration of ICAM at
       cell sites where most virions are released may account for the
       acquisition of these membrane proteins by the HIV-1 progeny, and may be
       important for the cell-mediated spread.
 DE    Antigens, CD/METABOLISM  Binding Sites  Cell Adhesion  Cell Adhesion
       Molecules/*METABOLISM  Cell Line  Cell Polarity  CD4-Positive
       T-Lymphocytes/ULTRASTRUCTURE/VIROLOGY  Human  HIV Core Protein
       p24/METABOLISM  HIV-1/*GROWTH & DEVELOPMENT/IMMUNOLOGY/*PHYSIOLOGY
       Intercellular Adhesion Molecule-1/METABOLISM  Lymphocyte
       Function-Associated Antigen-1/METABOLISM  Microscopy, Electron  Support,
       Non-U.S. Gov't  Viral Matrix Proteins/*METABOLISM  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

