Distribution of O-acetylated sialomucin in the normal and diseased gastrointestinal tract shown by a new monoclonal antibody.

Abstract

AIMS:

To produce and characterise a monoclonal antibody specific for O-acetylated sialomucin and to assess its use in immunohistochemistry on a panel of normal and diseased intestinal tissue samples.

METHODS:

Mouse monoclonal antibodies were developed following immunisation with highly purified human colonic mucin. One of these (MMM-17) showed strong binding to mucin throughout the normal colon with relative lack of binding to colon cancer tissue. The binding epitope of MMM-17 was then characterised by screening for agglutination activity against a panel of human and animal erythrocytes and by assessment of its binding to a range of normal and chemically treated slot blotted mucins. Further immunohistochemical studies were then performed on formalin fixed, normal, and diseased human intestinal samples.

RESULTS:

Binding of MMM-17 to slot blotted human colonic mucin was reduced by 38 (SD 14%) (n = 4) by alkali treatment of the mucin, sequential alkali and sialidase treatment completely abolished binding. Sialidase treatment alone, however, caused only an 11 (11%) reduction in binding. MMM-17 failed to agglutinate any human, rabbit, rat or mouse erythrocytes. These findings were compatible with specificity of MMM-17 for sialomucins O-acetylated at the C-7 or C-8 positions on the sialic acid. Strong staining by MMM-17 was found in all goblet cells throughout all 40 normal colonic and rectal samples studied, but staining was absent in seven of 13 colorectal carcinomas. Normal duodenum (n = 16) and normal ileum (n = 3) all showed occasional positive goblet cells. The normal gastric antral mucosa was generally negative B MMM-17, but in all of 15 cases of gastritis with intestinal metaplasia the metaplastic glands were strongly positive for MMM-17.

CONCLUSION:

Monoclonal antibody MMM-17 has specificity for O-acetylated sialomucins and its binding depends both on the position of O-acetylation and on the adjacent oligosaccharide structure. Preliminary studies using the antibody on archival tissue samples support the previous reports of reduced O-acetylation in colon cancer demonstrated by indirect histochemistry and show the neo-formation of O-acetylated sialomucin in intestinal metaplasia in the stomach.

• Authors: J D Milton, D Eccleston, N Parker, A Raouf, C Cubbin, J Hoffman, C A Hart, J M Rhodes
• Journal: Journal of clinical pathology (J Clin Pathol) Vol. 46 Issue 4 Pg. 323-9 (Apr 1993) ISSN: 0021-9746 [Print] England
• PMID: 8496389 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Monoclonal
• Mucins
• Sialomucins

Topics

• Animals
• Antibodies, Monoclonal (metabolism)
• Antibody Specificity
• Colonic Neoplasms (chemistry)
• Digestive System (chemistry)
• Enzyme-Linked Immunosorbent Assay
• Gastric Mucosa (pathology)
• Gastrointestinal Diseases (metabolism)
• Humans
• Immunoenzyme Techniques
• Metaplasia (metabolism)
• Mice
• Mice, Inbred BALB C
• Mucins (analysis)
• Sialomucins