Tropomyosin isoforms in intestinal mucosa: production of autoantibodies to tropomyosin isoforms in ulcerative colitis.
OBJECTIVE
Autoantibodies against tropomyosins (TMs) have been reported in ulcerative colitis (UC). In this study the hTM isoforms (hTM1-5) present in intestinal epithelial cells and in smooth muscle were investigated, and the immunoreactivity against hTMs by immunoglobulin G (IgG) produced in vitro by colonic mucosal lymphocytes (LPMCs) from patients with UC, Crohn's disease (CD), and controls was examined.


METHODS
TMs were extracted from colonic and jejunal epithelial cells and smooth muscle, and hTM isoforms were identified using isoform-specific monoclonal antibodies by enzyme-linked immunosorbent assay and transblot analysis. The immunoreactivity of IgG produced by colonic LPMCs was analyzed against the recombinant hTM isoforms.


RESULTS
The major hTM isoforms present in colonic and jejunal epithelial cells are hTM5 and hTM4, whereas intestinal smooth muscle contains the hTM1-3 isoforms. The IgG synthesized in vitro by LPMCs from UC (n = 19) recognized hTM5 and hTM1, more significantly (P < 0.04 to <0.001) when compared with CD (n = 12) and controls (n = 17). However, IgG produced by LPMCs from CD did not show such anti-hTM reactivity. Mucosal anti-hTM IgG mainly belonged to the IgG1 subclass.


CONCLUSIONS
Intestinal epithelial cells and smooth muscle have distinct hTM isoforms. Patients with UC, and not CD, show mucosal autoantibody response against hTM isoforms, particularly hTM5 and hTM1.
Geng
X
X
Division of Gastroenterology and Hepatology, Department of Medicine, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, New Jersey 08903, USA.
Biancone
L
L
Dai
H H
HH
Lin
J J
JJ
Yoshizaki
N
N
Dasgupta
A
A
Pallone
F
F
Das
K M
KM
D000328:Adult; D000368:Aged; D000906:Antibodies / Q000032:analysis; D001323:Autoantibodies / Q000276:immunology*; D003093:Colitis, Ulcerative / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D003424:Crohn Disease / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000473:pathology; D007536:Isomerism; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D014335:Tropomyosin / Q000276:immunology* / Q000378:metabolism*
D000906:Antibodies; D001323:Autoantibodies; D007074:Immunoglobulin G; D014335:Tropomyosin