Y. Mizukawa et al., Immunohistochemical detection of skin-homing T cells expressing fucosyltransferase VII (Fuc-TVII) in vitro and in situ, LAB INV, 81(5), 2001, pp. 771-773
Although expression of cutaneous lymphocyte-associated antigen (CLA) is tho
ught to be a specific marker of skin "homing" T cells, it has become clear
that CLA is a good marker for high levels of fucosyltransferase VII (Fuc-TV
II) activity but does not necessarily represent the epitope required for bi
nding to E-selectin (Wagers et al, 1996, 1997). Therefore, expression of Fu
c-TVII is an attractive candidate for identifying skin "homing" T cells. Ho
wever, analyses of Fuc-TVII expression in human T cells have been performed
only at the mRNA level (Nakayama et al, 2000) because of the lack of mAb.
In this study Fuc-TVII was for the first time visualized in individual cell
s by using a novel mAb that we developed. Double immunofluorescence and imm
unohistochemistry demonstrated the coexpression of Fuc-TVII and CLA in cell
lines in which Fuc-TVII mRNA was shown to be expressed at high levels: whe
reas CLA expression was seen in the cell membrane, Fuc-TVII was identified
in a supra- or perinuclear location. Cytoplasmic Fuc-TVII expression was al
so detectable in both CD4(+) and CD8(+) T cells purified from peripheral bl
ood. Fuc-TVII was also expressed at high levels in many CLA(+) T cells infi
ltrating the skin. In these peripheral T cells, unlike in cell lines, cytop
lasmic expression of Fuc-TVII was not always associated with surface CLA ex
pression. This mAb would serve as a valuable tool for selectively identifyi
ng a novel subset of skin "homing" T cells that are not detected by the con
ventional method because of the lack of CLA expression.