Intestinal transport and catabolism of IgE: a major blood-independent pathway of IgE dissemination during a Trichinella spiralis infection of rats
Negrão-Corrêa, D.; Adams, L.S.; Bell, R.G.
Journal of Immunology 157(9): 4037-4044
1996
ISSN/ISBN: 0022-1767 PMID: 8892637 Document Number: 463071
In this study, AO rats (2 to 3-months-old) were each inoculated orally with 2000 infective Trichinella spiralis larvae. IgE levels in the small intestine lumen, draining thoracic duct lymph and serum were measured by ELISA. Total IgE levels in intestinal fluid from infected rats were elevated by 4 days pi, but were not elevated in serum and lymph until 7 days pi. IgE levels in the whole intestine wash sample ranged from 1-6 micro g between 10 and 21 days pi, and serum and lymph IgE levels ranged from 100-200 ng/ml. In serum a maximum level of 220 ng/ml of total IgE was reached at 14 days pi. Immunoprecipitation of intestinal fluid and enterocyte lysate at 11 days pi showed a protein of 190 kDa that was recognized by mouse anti-rat IgE-MARE-1 in Western blots. This protein was removed from intestinal wash samples with anti-IgE (A2)-Sepharose. Radiolabelled IgE ([125I]IgE) showed that the half-life of intact IgE in the intestinal lumen of rats at 10 days pi was 3.25 min; in serum, the half-life of IgE was 5 h. Analysis of IgE production and consumption at 10 days pi showed that approximately 4.67 micro g IgE per day entered the serum, while 2570 micro g IgE per day entered the intestinal lumen. It is concluded that the IgE present in serum at 10 days pi originated in the gut and/or associated lymphoid tissue and was transported to the circulation via thoracic duct lymph.