Little is known about the precise mechanism of loading of peptides derived from HIV-1 onto MHC-II molecules expressed by antigen presenting cells (APC). This loading of HIV specific peptide on MHC-II molecules is essential for the activation of both na?ve and specific CD4+ T cells. It must occur because CD4- T cell responses can be demonstrated in some HIV-infected persons, and CD4+ T cell help is required to generate the anti-HIV humoral immune responses observed in patients. ? ? Hypothesis: 1. That HIV enters APC through a combination of specific receptor mediated mechanisms and nonspecific mechanisms some of which lead to rapid presentation of HIV peptides on MHC-II before productive infection occurs. 2. That different forms of HIV (HIV-1 virions, live or apoptotic HIV-infected cells, and HIV-containing exosomes) are presented on MHC-II with different efficiencies.
Specific Aim 1. To determine the mechanism(s) used by APC to internalize and process HIV-1 for presentation on MHC-II molecules. HLA-DR restricted T cell hybridomas that recognize HIV antigens presented by human DC and macrophages will be used. T cell hybridomas serve as a bioassay for specific peptide:MHC complexes. This system will allow the use antibody and pharmacologic inhibitors to study the mechanisms of uptake, processing, and presentation of HIV-1. These studies will be performed in monocyte derived DC, monocyte derived macrophages, primary blood myeloid and plasmacytoid DC, and primary DC and macrophages from colonic and cervicovaginal mucosa. Quantitative analysis of intracellular trafficking of HIV in DC will be performed by high-resolution microscopy.
Specific Aim 2. To determine the form of HIV-1 or HIV-1 antigen most efficiently processed and presented by MHC-II molecules. MHC-II antigen presentation of HIV-1 virions, HIV infected cells (live and apoptotic), and HIV-containing exosomes will be studied in human monocyte derived and primary APC. ? ? A better understanding of MHC-II antigen presentation of HIV-1 will aid in understanding events early ? in infection when CD4+ T cells are primed and the character of CTL and B cell responses is being ? determined by the quality of CD4+ T cell help they receive. A better understanding of the optimal forms of HIV antigen for presentation will aid in vaccine design and development. Knowledge gained may help aid in developing strategies to modulate HIV infection in APC to bias toward degradative pathways and not those that result in productive infection or trans-infection of CD4+ T cells. ? ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AI073217-02
Application #
7469545
Study Section
AIDS Immunology and Pathogenesis Study Section (AIP)
Program Officer
Embry, Alan C
Project Start
2007-07-15
Project End
2010-06-30
Budget Start
2008-07-01
Budget End
2010-06-30
Support Year
2
Fiscal Year
2008
Total Cost
$189,456
Indirect Cost
Name
Case Western Reserve University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106
Simmons, Daimon P; Wearsch, Pamela A; Canaday, David H et al. (2012) Type I IFN drives a distinctive dendritic cell maturation phenotype that allows continued class II MHC synthesis and antigen processing. J Immunol 188:3116-26
El Fenniri, L; Toossi, Z; Aung, H et al. (2011) Polyfunctional Mycobacterium tuberculosis-specific effector memory CD4+ T cells at sites of pleural TB. Tuberculosis (Edinb) 91:224-30
Canaday, D H; Burant, C J; Jones, L et al. (2011) Preserved MHC-II antigen processing and presentation function in chronic HCV infection. Cell Immunol 266:187-91
Woc-Colburn, Laila; Smultea, Lavinia; Ramachandra, Lakshmi et al. (2010) Preserved MHC class II antigen processing in monocytes from HIV-infected individuals. PLoS One 5:e9491
Simmons, Daimon P; Canaday, David H; Liu, Yi et al. (2010) Mycobacterium tuberculosis and TLR2 agonists inhibit induction of type I IFN and class I MHC antigen cross processing by TLR9. J Immunol 185:2405-15
Reuter, Morgan A; Pecora, Nicole D; Harding, Clifford V et al. (2010) Mycobacterium tuberculosis promotes HIV trans-infection and suppresses major histocompatibility complex class II antigen processing by dendritic cells. J Virol 84:8549-60
Canaday, David H; Wu, Mianda; Lu, Shigou et al. (2009) Induction of HIV type 1 expression correlates with T cell responsiveness to mycobacteria in patients coinfected with HIV type 1 and Mycobacterium tuberculosis. AIDS Res Hum Retroviruses 25:213-6