Expression of β-1,4-galactosyltransferase I in CD4^＋ TH cells and its effect on cellular adhesion ability

Objective To study the expression and localization of β-1,4-galactosyltransferase I （β-1,4- GaIT I ）in CD4^＋ helper T（TH ）lymphocytes and the effect of β-1,4-GalT I on adhesion ability of CD4^＋ TH ceils. Methods CD4^＋ TH ceils were isolated by CD4 positive immunomagnetic beads. The expression and localization of β-1,4-GAIT I in CD4^＋ TH cells was detected by RT-PCR, immunofluorescence and laser scanning confocal microscopy. Activation and differentiation of CD4^＋ TH ceils were introduced by cytokines such as rhIL-2, rhIL-12 and rhIL-4. The expression level of β-1,4-GalT I in CD4^＋ TH cells was measured by semi-quantitative RT-PCR and flow cytometry. The adhesion ability of CD4^＋ TH cells was compared by ceil adhesion assay, α-lactalbumin was used to interfere the activity and substrate specificity of ceil surface β-1,4-GalT I , then the influence of that on the adhesion ability of CD4^＋ TH ceils was analyzed by ceil adhesion assay. Results long and short β-1,4-GaiT I were expressed and localized on the cytomembrane and cytoplasm of CD4^＋ TH ceils. The expression level of long β- 1,4-GalTI and cell surface β-1,4-GalTI , and the adhesion ability of CD4^＋ TH ceils activated with rhIL-2 in- creased as compared with unactivated CD4＋ TH cells. The expression level of long β-1,4-GalT I and ceil surface β-1,4-GAIT I were both positively correlated with the adhesion ability of CD4^＋ TH ceils. The adhesion ability of CD4^＋ TH ceils decreased after the incubation with α-lactalbumin. Conclusion β-1,4-GalT I expression in CD4^＋ TH ceils is closely correlated with ceil adhesion ability, which suggests that β-1,4-GalT I may play an important role in the adhesion process of CD4^＋ TH cells. Key words: β-1,4-galactosyltransferase I ;  CD4^＋ helper T lymphocytes;  Cellular adhesion