Summary:

To study the effects of nagalase on the bioactivity of GcMAF.A cancer cell line with high levels of nagalase, produced by the human salivary gland (HSG), was studied.GcMAF prepared enzymatically was able to activate macrophages.However, GcMAF treated with nagalase did not do this.Thus, salivary gland cancer in this study was able to produce large quantities of nagalase, which inactivates GcMAF produced from GcProtein, resulting in reduced phagocytic activity.This study suggests that HSG nagalase acts as an immunodeficiency factor in cancer patients.

Abstract

The aim of this study was to clarify the effects of alpha-N-acetylgalactosaminidase (alpha-NaGalase) produced by human salivary gland adenocarcinoma (SGA) cells on the bioactivity of macrophage-activating factor (GcMAF). High exo-alpha-NaGalase activity was detected in the SGA cell line HSG. HSG alpha-NaGalase had both exo- and endo-enzyme activities, cleaving the Gal-GalNAc and GalNAc residues linked to Thr/Ser but not releasing the [NeuAc2-6]GalNac residue. Furthermore, GcMAF enzymatically prepared from the Gc protein enhanced the superoxide-generation capacity and phagocytic activity of monocytes/macrophages. However, GcMAF treated with purified alpha-NaGalase did not exhibit these effects. Thus, HSG possesses the capacity to produce larger quantities of alpha-NaGalase, which inactivates GcMAF produced from Gc protein, resulting in reduced phagocytic activity and superoxide-generation capacity of monocytes/macrophages. The present data strongly suggest that HSG alpha-NaGalase acts as an immunodeficiency factor in cancer patients.