Novel HIV Neutralizing Human MAbs from Transgenic Mice

Project Details

Description

DESCRIPTION: This project will use the transgenic "XenoMouse" system, developed
by Abgenix, to isolate novel human monoclonal antibodies against HIV-1 which
possess potential clinical utility. These mice contain -2 megabases of the
human Ig heavy and kappa light chain loci that functionally recapitulate the
human humoral immune system. In preliminary studies, we have immunized Xenomice
with a number of HIV envelope antigens, including recombinant fusion proteins
expressing several of the variable loop domains of the viral surface protein,
and a recombinant gpl20 derived from the primary virus isolate, SF162. This
latter antigen was uccessful in eliciting Mabs that recognized native viral
envelope proteins, including antibodies with potent neutralizing activities for
the SF162 strain. Multiple types of epitopes were recognized, including some
that had not been previously described. Domains recognized by neutralizing Mabs
included the CD4-binding domain and other conserved conformational epitopes in
gpl20, as well as sites in the V3 and V1/V2 hypervariable regions. The most
potently neutralizing antibodies were directed against type-specific V1/V2
epitopes. In further proposed studies, the epitopes recognized by current
neutralizing antibodies will be fully characterized, and the complete range of
their neutralizing activities determined. Additional immunizations will be
performed with related gpl20 immunogens derived from additional strains,
including non-clade B strains. In order to elicit antibodies to native epitopes
important for neutralization that may not survive gpl20 purification,
immunizations will also be performed with native envelope complexes expressed
on virion particles and on mouse B cells expressing the complete e n v gene.

Immunizations will also be performed with viral particles expressing the HIV
receptors, CD4, CCR5 and CXCR4, on their surfaces, as well as with mixtures of
particles expressing both Env and HIV receptors, in order to generate human
antibodies against 'activated gpl20' epitopes, or against the receptors
themselves. To facilitate the identification of antibodies with functional
activities, hybridomas will be screened directly by a sensitive neutralization
assay, in addition to traditional binding assays. Epitopes recognized by Mabs
with neutralizing activities will be fully mapped, and the full range of
antiviral activities of interesting Mabs will be characterized. It is
anticipated that these studies should help define the diversity of
neutralization epitopes present both on the surface of HIV-1 and its cellular
receptors. Ultimately, these studies may lead to the generation of a cocktail
of novel human Mabs with antiviral activities against multiple clinical
strains, that could serve as an effective immunotherapeutic reagent to control
and prevent HIV infection.
StatusFinished
Effective start/end date2/1/021/31/08

Funding

  • National Institute of Allergy and Infectious Diseases: $389,000.00
  • National Institute of Allergy and Infectious Diseases: $389,000.00

ASJC

  • Immunology

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