       Document 0104
 DOCN  M9620104
 TI    Construction and characterization of a Salmonella typhi-based human
       immunodeficiency virus type 1 vector vaccine.
 DT    9602
 AU    Fouts TR; Lewis GK; Hone DM; Department of Geographic Medicine, School
       of Medicine, University; of Maryland at Baltimore 21201, USA.
 SO    Vaccine. 1995 Apr;13(6):561-9. Unique Identifier : AIDSLINE MED/96065464
 AB    Since the human immunodeficiency virus type 1 (HIV-1) is transmitted
       either parenterally or sexually, both systemic and mucosal immune
       responses might be required to provide protective immunity. One option
       is to express HIV proteins in attenuated Salmonella vectors that elicit
       immune responses in both compartments. The first step to constructing
       such a strain was achieved by integrating a gene expression cassette
       encoding recombinant HIV-1 gp120 (rgp120) into the aroC locus of an
       attenuated vaccine strain of S. typhi. This rgp120 expression cassette
       utilizes the strong constitutive promoter, P1pp/lacUV5, and produces
       rgp120 to 0.05-01% of the total bacterial cell protein. Immunoblot
       analysis shows that the S. typhi strains containing the integrated
       cassette express a protein that is both recognized by anti-gp120
       monoclonal antibodies (mAbs) and is the appropriate size for
       nonglycosylated full-length gp120 (52 kDa). Immunoblot analysis also
       demonstrates that the recombinant S. typhi strains express the rgp120 as
       monomers and multimers found predominantly in the insoluble fraction of
       the bacteria. Antigen-capture ELISA, using antibodies specific for
       continuous epitopes on gp120, revealed that the exposure of these
       epitopes on S. typhi-expressed rgp120 differs from exposure of these
       epitopes on baculovirus-expressed rgp120 that binds CD4. Epitopes in the
       first conserved region (109-113) and the third conserved/fourth variable
       regions (376-380, 382-384, 395-400) are more surface-exposed, while one
       epitope in the third variable region (313-324) is more buried relative
       to the corresponding epitopes of baculovirus expressed gp120. Antibodies
       recognizing discontinuous epitopes of the CD4 binding domain do not
       react with the S. typhi expressed rgp120.(ABSTRACT TRUNCATED AT 250
       WORDS)
 DE    AIDS Vaccines/*GENETICS/IMMUNOLOGY  B-Lymphocytes/IMMUNOLOGY  Base
       Sequence  Cloning, Molecular  Comparative Study  Epitopes/IMMUNOLOGY
       Genetic Vectors  HIV Envelope Protein gp120/*GENETICS/*IMMUNOLOGY
       HIV-1/*IMMUNOLOGY  Molecular Sequence Data  Mutagenesis, Insertional
       Recombinant Proteins/GENETICS/IMMUNOLOGY  Salmonella
       typhi/*GENETICS/METABOLISM  Support, Non-U.S. Gov't  Support, U.S.
       Gov't, P.H.S.  Vaccines, Attenuated/GENETICS/IMMUNOLOGY  JOURNAL ARTICLE

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

