Expression of CD34 and L-selectin on human corneal keratocytes.
OBJECTIVE
To investigate the expression of CD34, a hematopoietic stem cell marker and an adhesion molecule, and its ligand L-selectin in the human cornea.


METHODS
Seventeen normal adult human corneal specimens were studied by immunohistochemistry using a panel of monoclonal antibodies against all three classes of the hematopoietic stem cell marker CD34 and its ligand L-selectin. An additional six corneal specimens were used for protein extraction and analysis by Western blotting, using the CD34 and L-selectin antibodies. PCR was used to determine expression of mRNA for CD34 and L-selectin in the corneal specimens.


RESULTS
Only corneal keratocytes showed positive immunostaining for all three classes of CD34. Western blotting confirmed the expression of CD34 by these cells and mRNA expression for CD34 in the corneal stroma was demonstrated by PCR. For L-selectin, positive staining around keratocytes was noted on immunohistochemistry but L-selectin could not be detected either by Western blotting or PCR.


CONCLUSIONS
Normal human corneal keratocytes express all three classes of CD34. The expression of this adhesion molecule on corneal keratocytes suggests that it may have a role in keeping the keratocytes anchored in their microniche, between the collagen lamellae. The positive staining for L-selectin found by immunohistochemistry but not by Western blotting or PCR would indicate the presence of either another ligand from the selectin family or a cross-reactive epitope on corneal keratocytes.
Larry A. Donoso Laboratory for Eye Research, Division of Ophthalmology and Visual Sciences, Eye, Ear, Nose, and Throat Centre, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom.
Annie
A
Joseph
Parwez
P
Hossain
Seema
S
Jham
Rhodri E
RE
Jones
Paddy
P
Tighe
Richard S
RS
McIntosh
Harminder S
HS
Dua
D000911:Antibodies, Monoclonal; D018952:Antigens, CD34 / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D003319:Corneal Stroma / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D019041:L-Selectin / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism
D000911:Antibodies, Monoclonal; D018952:Antigens, CD34; D012333:RNA, Messenger; D019041:L-Selectin