BACKGROUND _ AIMS: The gut is the largest immunologic organ in the @entity1 body, but little is known about the antigen specificity of @entity33 cells. This study sought to determine whether T cells resident in the duodenal mucosa could recognize astrovirus, a common and clinically important @entity1902 virus. Serum antibodies against astrovirus are prevalent, indicating frequent viral exposure and postinfectious induction of systemic immune responses. Mucosal immune responses may conceivably mediate protection on astroviral reinfections. METHODS: Small intestinal biopsy specimens with normal histology were obtained from 8 adults and challenged in an organ culture system with inactivated @entity11679 . T cells activated by the viral challenge were isolated either by immunomagnetic positive selection of mucosal resident cells or by collecting cells emigrating into the culture supernatant. RESULTS: Astrovirus-specific, @entity33 -cell lines were isolated from all 8 subjects. Analysis of 29 @entity404 + T-cell clones from 3 subjects showed predominant HLA-DR restriction of astrovirus responses. Most of the T-cell clones showed a @entity1198 -like cytokine profile when restimulated with astrovirus. CONCLUSIONS: Helper T cells residing in normal, duodenal mucosa of adult subjects recognize a common enteropathogenic virus. These mucosal @entity404 + T cells are presumably important in @entity33 against recurrent @entity281 .

@entity404 + T cells with specific reactivity against astrovirus isolated from normal XXXX small intestine.

@entity1 :: ('9606', 'Species') :: ['human'] @entity404 :: ('920', 'Gene') :: ['CD4'] @entity33 :: ('MESH:D052016', 'Disease') :: ['mucosal defense', 'mucosal T'] @entity11679 :: ('12702', 'Species') :: ['human astrovirus'] @entity1198 :: ('51497', 'Gene') :: ['Th1'] @entity1902 :: ('MESH:D005759', 'Disease') :: ['gastroenteritis'] @entity281 :: ('MESH:D007239', 'Disease') :: ['astroviral infections']
@entity1 :: (9606,Species) :: ['human']
