This project addresses the hypothesis that gp96, a heat shock protein that has been implicated in antigen presentation in mammals, is part of an ancestral pathway that is antecedent to, and independent of, the antigen presentation pathway that uses MHC molecules. We will test this hypothesis by exploring the role of gp96 in immune processes in the frog, Xenopus. Moreover, since the Amphibia occupy a pivotal position in the evolution of vertebrates, it is anticipated that if our hypothesis is correct, gp96 should be involved in immune processes in frogs as well as mammals. Since premetamorphic immunocompetent Xenopus tadpoles do not express cell surface MHC class I molecules, the frog model allows us to explore the role of gp96 in immune processes in the absence (larvae) and presence (adults) of MHC class I-dependent presentation pathways. To begin to determine whether gp96 is involved in immune processes in Xenopus, four specific aims will be addressed.
Aim 1 deals with the hypothesis that gp96 purified from normal Xenopus tissues can bind peptides. This hypothesis will be tested by examining the ability of Xenopus gp96 loaded with peptides from vesicular stomatitis virus and ovalbumin to prime murine CTL clones. In addition to determining whether Xenopus gp96 is normally associated with native peptides, we will clone the Xenopus gp96 homologue and determine the degree to which its primary structure, particularly its putative peptide-binding domain, has been conserved. In addition, cloning the gp96 homologue of Xenopus will provide useful tools to determine whether this gp96 gene is linked to genes of the MHC (like hsp70) or to genes encoding other members of the hsp90 family; and determine whether its promoter contains an IFN-gamma-responsive element.
Aim 2 focuses on testing the hypothesis that if Xenopus gp96 is involved in antigen presentation and/or immunomodulation, it may be detectable as a cell surface molecule. Recent data reveal cell surface gp96 on a subset of adult Xenopus B-cells, on larval lymphocytes, and on lymphocytes from teleosts and hagfish. Experiments are proposed to further characterize the pattern of this cell surface gp96 on lymphocytes from MHC class I+ adults and MHC class I- larvae.
Aims 3 and 4 develop the novel hypothesis that in vivo, the immunogenicity of gp96 may be revealed by its capacity to evoke accelerated rejection of minor H-antigen disparate skin allografts in adults, and tolerance of the same grafts in larvae. Experiments to evaluate the specificity and peptide complex-dependency of these putative alloimmune reactivities are presented as are experiments to reveal the nature of effector cells involved.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
3R01AI044022-03S1
Application #
6605215
Study Section
Special Emphasis Panel (ZRG1 (02))
Program Officer
Gondre-Lewis, Timothy A
Project Start
2000-04-01
Project End
2004-03-31
Budget Start
2002-04-01
Budget End
2003-03-31
Support Year
3
Fiscal Year
2002
Total Cost
$11,165
Indirect Cost
Name
University of Rochester
Department
Microbiology/Immun/Virology
Type
Schools of Dentistry
DUNS #
208469486
City
Rochester
State
NY
Country
United States
Zip Code
14627
Kinney, Kevin S; Cohen, Nicholas (2009) Neural-immune system interactions in Xenopus. Front Biosci (Landmark Ed) 14:112-29