Our objective is to define the mechanisms that control lymphocyte trafficking in the GI tract, focusing on the colon vs. small intestines (SI), and to characterize their roles in targeting effector and memory cells to mucosal immunogens. Our underlying hypothesis is that specialized mechanisms differentiate lymphocyte trafficking along the digestive tract, and allow regional segregation and specialization of gastrointestinal immune responses.
Aim 1 : To identify colon-homing T cells, and determine whether colonic immunization imprints selective colon homing properties on responding T cells: The homing of T cells to the colon is poorly understood. Short-term homing assays will be used to identify T cell subsets that home optimally to the colon;to seek subsets that can home selectively to the colon vs. the small intestines;and to test the hypothesis that colonic immunization imprints specialized colon-selective trafficking programs on antigen-reactive T cells.
Aim 2 : To identify known and candidate novel trafficking receptors expressed by colon- and SI-homing T cell populations. Immunofluorescence and gene microarray studies will be used.
Aim 3 : To define the molecular mechanisms of T cell recruitment to the colon vs. small intestines, and the role(s) of colon- and small intestine- selective T cell chemoattractant and orphan G protein linked receptors (GPCRs): Short term homing studies using blocking monoclonal antibodies and gene-targeted lymphocytes will be used to test the hypothesized role of expressed trafficking receptors, including novel candidate colon- and SI-specific GPCRs, in T cell homing to normal or inflamed colon or SI. Mixed bone marrow chimeras will be generated to test the effects of genetic deletion of candidate GPCR SI and colon trafficking receptors on T cell repopulation and microenvironmental positioning within the GI tract. Understanding lymphocyte recruitment to normal and inflamed intestines may lead to novel therapeutic approaches in inflammatory bowel diseases, as well as providing insights that can improve methods of vaccination and monitoring of mucosal immunity to intestinal pathogens, and to HIV. 69

Public Health Relevance

Immune cells need to gain access to the gut wall to provide protection against pathogenic organisms, but they can also cause pathologic inflammation for example in inflammatory bowel diseases (IBD). We propose to define the molecules that control lymphocyte trafficking from the blood circulation into the intestines, particularly those that mediate immune cell recruitment into the colon and small intestines. Understanding lymphocyte recruitment to normal and inflamed intestines may lead to novel therapeutic approaches in IBD, as well as providing insights that can improve methods of vaccination and monitoring of mucosal immunity to HIV, SARS, rotavirus and other infectious agents.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37AI047822-13
Application #
8440353
Study Section
Immunity and Host Defense Study Section (IHD)
Program Officer
Rothermel, Annette L
Project Start
2000-08-01
Project End
2016-02-29
Budget Start
2013-03-01
Budget End
2014-02-28
Support Year
13
Fiscal Year
2013
Total Cost
$326,650
Indirect Cost
$91,650
Name
Palo Alto Institute for Research & Edu, Inc.
Department
Type
DUNS #
624218814
City
Palo Alto
State
CA
Country
United States
Zip Code
94304
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