HIV disease is characterized by high level CD8+ T cell activation and impairment in T cell function. Despite being the distinguishing characteristic of HIV-1 infection, the basis for the variation in CD8+ T cell activation in humans is not well understood. Variation in circulating strains of HIV-1 may account for this variation. We intend to map viral genetic determinants of T cell activation within the HIV-1 Nef protein. The HIV-1 Nef protein has been repeatedly implicated in manipulation of the human immune system. Adopting a very wide array of functions, HIV-1 Nef down modulates expression of key surface receptors, such as CD4, CD28, and MHC, facilitates viral entry and release, directly interacts with signaling proteins, such as the T cell receptor proximal kinase, Lck, and induce IL-2 expression. The sites c ? onferring these functions to Nef fall in distinct regions of the protein - regions which vary in sequence across HIV-1 strains. Nef is expressed early in infection, and is a target for CTL immune escape. HIV-1 Nef activity within infected CD4+ T cells influences cellular response to stimuli, cytokine secretion patterns, and interaction with CD8+ T cells. In this way, Nef may influence CD8+ T cell activation levels and T cell maturation. While Nef has been studied extensively in vitro, the impact of Nef sequence variation in vivo has not been well studied. We propose to relate HIV-1 viral nef sequence to T cell activation levels, T cell phenotype, and T cell signaling alterations by use of advanced bioinformatic mapping tools. We will perform these studies in a cohort of 220 recently HIV-1 infected adults with well-characterized disease course and in collaboration with the UCSF/CFAR Core Immunology Laboratory and the UCSF Laboratory of Clinical Virology. We will use tree- structured biostatistical methods and their extensions which are well suited to handling of high-dimensional biological data types, such as genetic sequence and flow cytometry. The strengths of this application include the availability of specimens from a well-characterized cohort of HIV-1 infected adults; the use of advanced bioinformatic mapping tools; high-dimensional flow cytometric measures of function and signaling; a highly qualified inter-disciplinary research team; and a longitudinal approach to study of a genetically diverse entity, HIV-1. This work will facilitate development of therapies to improve the effectiveness of T cell responses and design of an effective HIV vaccine. HIV disease is characterized by high level CD8+ T cell activation and impairment in T cell function. Despite being the distinguishing characteristic of HIV-1 infection, the basis for the variation in CD8+ T cell activation in humans is not well understood. Variation in circulating strains of HIV-1 may account for this variation. We intend to map viral genetic determinants of T cell activation within the HIV-1 Nef protein. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AI076014-02
Application #
7433916
Study Section
AIDS Clinical Studies and Epidemiology Study Section (ACE)
Program Officer
Gezmu, Misrak
Project Start
2007-06-15
Project End
2010-05-31
Budget Start
2008-06-01
Budget End
2010-05-31
Support Year
2
Fiscal Year
2008
Total Cost
$113,306
Indirect Cost
Name
University of California San Francisco
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Crawford, Timothy Q; Jalbert, Emilie; Ndhlovu, Lishomwa C et al. (2014) Concomitant evaluation of PMA+ionomycin-induced kinase phosphorylation and cytokine production in T cell subsets by flow cytometry. Cytometry A 85:268-76
Crawford, Timothy Q; Hecht, Fredrick M; Pilcher, Christopher D et al. (2013) Activation associated ERK1/2 signaling impairments in CD8+ T cells co-localize with blunted polyclonal and HIV-1 specific effector functions in early untreated HIV-1 infection. PLoS One 8:e77412
Ndhlovu, Lishomwa C; Lopez-Verg├Ęs, Sandra; Barbour, Jason D et al. (2012) Tim-3 marks human natural killer cell maturation and suppresses cell-mediated cytotoxicity. Blood 119:3734-43
Crawford, Timothy Q; Ndhlovu, Lishomwa C; Tan, Alice et al. (2011) HIV-1 infection abrogates CD8+ T cell mitogen-activated protein kinase signaling responses. J Virol 85:12343-50
Long, Brian R; Erickson, Ann E; Chapman, Joan M et al. (2010) Increased number and function of natural killer cells in human immunodeficiency virus 1-positive subjects co-infected with herpes simplex virus 2. Immunology 129:186-96
Favre, David; Lederer, Sharon; Kanwar, Bittoo et al. (2009) Critical loss of the balance between Th17 and T regulatory cell populations in pathogenic SIV infection. PLoS Pathog 5:e1000295
Long, Brian R; Ndhlovu, Lishomwa C; Oksenberg, Jorge R et al. (2008) Conferral of enhanced natural killer cell function by KIR3DS1 in early human immunodeficiency virus type 1 infection. J Virol 82:4785-92