Junko Goto

Inactivation of interleukin-8 by aminopeptidase N (CD13).

Aminopeptidase (APN) was found to degrade interleukin‐8 (IL‐8) and inactivate its chemotactic activity. The chemotactic activity of IL‐8 was decreased by APN or neutrophil plasma membranes dose‐ and time‐dependently. The chemotactic activity was not inactivated in the presence of bestatin or WM15 monoclonal antibody. The expression of IL‐8 was measured by flow cytometry. On lipopolysaccharide (LPS) stimulation, IL‐8 expression increased for 60 min and then decreased markedly. In contrast, on treatment with LPS and bestatin, the expression of IL‐8 increased continuously for at least 120 min. These results suggest that the expression and release of IL‐8 from phagocytic cells are regulated by the proteolytic effect of APN on IL‐8. J. Leukoc. Biol. 57: 129–134; 1995.

Changes in oligosaccharide expression on plasma membrane of the mouse oocyte during fertilisation and early cleavage.

It has been reported that various structural and functional changes occur on the surface of the plasma membrane of the ovum and embryo during fertilisation and cleavage in preparation for implantation. Glycoproteins are thought to be one of the factors in cell attachment. Thus, we investigated the changes in glycoprotein expression on the cell surface membrane of the mouse embryo by using lectins. Among seven types of lectin (ConA, WGA, UEA-I, MPA, LCA, DBA and PNA), the fluorescent intensities of ConA and WGA markedly increased from unfertilised ova to blastocysts. By quantitative analysis using immuno-scanning electron microscopy, the numbers of ConA-gold particles were small until 4-cell cleavage, but increased significantly at the blastocyst stage. In contrast, an increased number of WGA-gold particles was detected even at the 4-cell stage, and this increase continued to the blastocyst stage. From the above observations, we conclude that the numbers of sugar chains bound to both ConA andWGA increases with blastocyst formation and earlier expression is observed with WGA. The present study dearly shows that glycoproteins on the cell membrane surface of the mouse embryo quantitatively increase at the time of implantation, and the possibility has been indicated that glycoproteins are involved in intercellular recognition and adhesion between the embryo and endometrial epithelium.