We seek to: (a) characterize the functional properties of antibodies (Abs) that bind HIV gp120 with irreversible character and catalyze the cleavage of the protein, (b) study the structural basis of these activities, and (c) study the neutralizing IgA responses induced by mucosal immunization with electrophilic gp120 analogs. The irreversibly binding Abs were raised by immunization with an electrophilic analog of full- length monomer gp120 and recognize two conserved peptide regions, one of which is a segment of the superantigenic site of gp120. The proteolytic Abs are naturally occurring human Abs that also recognize the superantigenic peptide region. Nucleophilic amino acids in the Ab combining sites are hypothesized to form dead-end irreversible complexes with gp120 or a covalent reaction intermediate that proceeds into the catalytic pathway, depending on the presence of accessory structural elements. As the structures of viral and monomer gp120 are different, we propose further study of Ab functional properties using intact virions as substrates. Neutralization studies will be done using peripheral blood mononuclear cells infected with diverse primary HIV isolates. Structural studies will entail identification of nucleophilic residues by crystallography, biochemical mapping and site-directed mutagenesis. Crystallography will also identify additional constituents of the nucleophilic site, the presence of the accessory catalytic structures (e.g., the oxyanion hole and water interacting residues), and the noncovalent binding contacts responsibe for the epitope specificity of the Abs. The Abs will be studied in unliganded state and complexed covalently to their peptide or peptide analog epitopes. To study whether the innate ability of IgAs to cleave gp120 can be recruited for defense against the virus, we will attempt to amplify the synthesis of neutralizing, proteolytic IgAs by mucosal immunization using our existing and novel electrophilic gp120 analogs. From these studies, we hope to identify the strengths and weaknesses of the Abs and immunogens relevant to HIV vaccination and therapy. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI067020-02
Application #
7341060
Study Section
AIDS Immunology and Pathogenesis Study Section (AIP)
Program Officer
Embry, Alan C
Project Start
2007-02-01
Project End
2012-01-31
Budget Start
2008-02-01
Budget End
2009-01-31
Support Year
2
Fiscal Year
2008
Total Cost
$437,589
Indirect Cost
Name
University of Texas Health Science Center Houston
Department
Pathology
Type
Schools of Medicine
DUNS #
800771594
City
Houston
State
TX
Country
United States
Zip Code
77225
Planque, Stephanie A; Mitsuda, Yukie; Chitsazzadeh, Vida et al. (2014) Deficient synthesis of class-switched, HIV-neutralizing antibodies to the CD4 binding site and correction by electrophilic gp120 immunogen. AIDS 28:2201-11
Planque, Stephanie A; Mitsuda, Yukie; Nishiyama, Yasuhiro et al. (2012) Antibodies to a superantigenic glycoprotein 120 epitope as the basis for developing an HIV vaccine. J Immunol 189:5367-81
Sapparapu, Gopal; Planque, Stephanie; Mitsuda, Yukie et al. (2012) Constant domain-regulated antibody catalysis. J Biol Chem 287:36096-104
Hanson, Carl V (2011) Vaccinogenicity. AIDS 25:581-4
Planque, Stephanie; Salas, Maria; Mitsuda, Yukie et al. (2010) Neutralization of genetically diverse HIV-1 strains by IgA antibodies to the gp120-CD4-binding site from long-term survivors of HIV infection. AIDS 24:875-84
Paul, Sudhir; Planque, Stephanie; Nishiyama, Yasuhiro et al. (2010) Back to the future: covalent epitope-based HIV vaccine development. Expert Rev Vaccines 9:1027-43
Paul, Sudhir; Planque, Stephanie A; Nishiyama, Yasuhiro et al. (2009) A covalent HIV vaccine: is there hope for the future? Future Virol 4:7-10
Planque, Stephanie; Nishiyama, Yasuhiro; Taguchi, Hiroaki et al. (2008) Catalytic antibodies to HIV: physiological role and potential clinical utility. Autoimmun Rev 7:473-9
Nishiyama, Yasuhiro; Mitsuda, Yukie; Taguchi, Hiroaki et al. (2007) Towards covalent vaccination: improved polyclonal HIV neutralizing antibody response induced by an electrophilic gp120 V3 peptide analog. J Biol Chem 282:31250-6