CD4 T helper cells are critical for the proper orchestration of the immune response and are essential for helping B cells make high affinity antigen-specific antibody. Follicular helper T (Tfh) cells are a recently characterized subset of CD4 T cells whose role is specifically to help B cells produce antibody, in part by promoting the germinal center reaction. However, deregulated development of Tfh cells can lead to autoimmune disease. Tfh cells are localized to B cell follicles and thus express the chemokine receptor CXCR5. Tfh cells are also characterized by high expression of the transcription repressor BCL6, and secretion of the B cell stimulatory cytokine IL-21. Recent data indicates that BCL6 is the master transcriptional regulator for Tfh cells: forced BCL6 expression can induce the Tfh phenotype in T cells, and Tfh cells cannot develop in the absence of BCL6. In this proposal, we seek to take advantage of the central role for BCL6 in Tfh development and function to better understand the link between Tfh cells and auto-immunity. Our hypothesis is that increased Tfh activity promoted by BCL6 can lead to non-specific antibody responses and eventually to autoimmunity, while blockade of BCL6 activity can block Tfh function and thus inhibit autoimmune disease progression. This hypothesis will be tested in the specific aims described below. This study will provide information that is critical for the manipulation of Tfh cells in vaccine development. Further, these experiments may lead to novel treatments for autoimmune diseases such as lupus.

Public Health Relevance

CD4 T helper cells are critical for the proper orchestration of the immune response, and CD4 T cells are particularly important in helping B cells in make antigen-specific antibody that fights disease. Follicular helper T (Tfh) cells are a recently discovered type of CD4 T cells whose role is specifically to help B cells produce antibody. However, Tfh cells can also promote autoimmune disease. Here we want to probe the relationship between Tfh cells and autoimmunity using a novel system, and also use a novel drug to block Tfh function. These studies may lead to new therapies for the treatment of autoimmune disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AI090150-02
Application #
8072744
Study Section
Hypersensitivity, Autoimmune, and Immune-mediated Diseases Study Section (HAI)
Program Officer
Rothermel, Annette L
Project Start
2010-05-15
Project End
2012-04-30
Budget Start
2011-05-01
Budget End
2012-04-30
Support Year
2
Fiscal Year
2011
Total Cost
$228,690
Indirect Cost
Name
Indiana University-Purdue University at Indianapolis
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
603007902
City
Indianapolis
State
IN
Country
United States
Zip Code
46202
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