Expression patterns of sialylated epitope recognized by KL-6 monoclonal antibody in ocular surface epithelium of normals and dry eye patients.
OBJECTIVE
To determine the association of the KL-6 epitope (sugar moiety) with MUC1 and its distribution on the ocular surface of human non-dry and dry eyes.


METHODS
The human ocular surface was examined immunohistochemically and immunoelectron microscopically using monoclonal antibody (mAb) KL-6, which recognize a carbohydrate epitope of MUC1. The expression patterns of KL-6 epitope in corneal and conjunctival cells were examined by impression cytology from 24 non-dry eye volunteers and 43 dry-eye patients.


RESULTS
In the cornea, bulbar conjunctiva, and limbus epithelium, mAb KL-6 reacted to the apical cell membrane of superficial cells and the intercellular space of superficial and wing cells. No immune reactivity of mAb KL-6 was observed in the basal plasma membrane of basal epithelial cells. Results of impression cytology indicated that the corneal epithelium of 13 of 24 non-dry eyes was weakly stained by mAb KL-6, whereas 42 of 43 dry eyes showed a mosaic pattern. In non-dry eyes, 19 of 24 bulbar conjunctival epithelia expressed the KL-6 epitope in a honeycomb pattern. In mild (17/19) and moderate (17/17) dry eye conjunctiva, the KL-6 epitope showed a mosaic pattern. However, the expression of KL-6 epitope decreased in severe dry eyes, showing a mosaic pattern in three of seven patients and labeling a few cells weakly in four of seven patients.


CONCLUSIONS
These findings suggest that there is an upregulation of the sialylated KL-6 epitope of MUC1 by apical corneal and conjunctival cells in mild and moderate dry eyes. This upregulation may in part alleviate the consequences caused by goblet cell mucin dysfunction in dry eyes. It is noteworthy that the KL-6 epitope is downregulated in the conjunctiva of severe dry eyes, a phenomenon that may be explained in part by the malfunction of conjunctival epithelial cells.
Hayashi
Yasuhito
Y
Department of Ophthalmology, Ehime University Medical School, Ehime, Japan. hayashy@email.uc.edu
Kao
Winston W-Y
WW
Kohno
Nobuoki
N
Nishihara-Hayashi
Miyuki
M
Shiraishi
Atsushi
A
Uno
Toshihiko
T
Yamaguchi
Masahiko
M
Okamoto
Shigeki
S
Maeda
Mitsuyo
M
Ikeda
Tomohiro
T
Hamada
Hironobu
H
Kondo
Keiichi
K
Ohashi
Yuichi
Y
D000911:Antibodies, Monoclonal / Q000276:immunology*; D000941:Antigens / Q000276:immunology / Q000378:metabolism*; D000951:Antigens, Neoplasm; D015415:Biomarkers; D003228:Conjunctiva / Q000378:metabolism* / Q000473:pathology; D015352:Dry Eye Syndromes / Q000378:metabolism* / Q000473:pathology; D004847:Epithelial Cells / Q000378:metabolism* / Q000473:pathology; D019573:Epithelium, Corneal / Q000378:metabolism* / Q000473:pathology; D000939:Epitopes / Q000276:immunology / Q000378:metabolism; D005260:Female; D006023:Glycoproteins / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018396:Mucin-1; D009077:Mucins / Q000276:immunology / Q000378:metabolism
D000911:Antibodies, Monoclonal; D000941:Antigens; D000951:Antigens, Neoplasm; D015415:Biomarkers; D000939:Epitopes; D006023:Glycoproteins; C060192:MUC1 protein, human; D018396:Mucin-1; D009077:Mucins