Expression of CD44 in human cumulus and mural granulosa cells of individual patients in in-vitro fertilization programmes

CD44 is a polymorphic and polyfunctional transmembrane glycoprotein widely expressed in many types of cells. Here, the expression of this protein on human membrana granulosa was studied by two techniques. Using confocal laser scanning microscopy (CLSM) with the mouse monoclonal antibody to human CD44 (clone G44-26), cells immunoreactive for CD44 were observed in both cumulus and mural granulosa cell masses. On the other hand, using monoclonal antibody to human CD44(v9), goat polyclonal antibody to human CD44(v3-10) and the clone G44-26, no immunoreactivity for CD44(v9) and/or CD44(v3-10), was observed in either cell group by flow cytometry. In the flow cytometric analysis of 32 patients, the incidence of CD44 expression in cumulus cells (62.6 +/- 1.3%) was significantly higher than that in mural granulosa cells (38.5 +/- 3.2%) (P < 0.0001). In the comparison of CD44 expression by flow cytometry according to the maturation of each cumulus-oocyte complex, the incidence of CD44 expression of cumulus cells was significantly higher in the mature group than in the immature group (P < 0.05). In a flow cytometric analysis, patients with endometriosis showed a significantly lower incidence of CD44 expression in cumulus cells compared to the infertility of unknown origin group (P < 0.05), and compared to both the male infertility group and the unknown origin group in mural granulosa cells (P < 0.01). These findings suggest that the standard form of CD44 is expressed in human membrana granulosa with polarity and may play an important role in oocyte maturation.