Purification Of A Lectin From Musca Domestica Pupae And Its Immune Activity

Musca domestica is an important resource in the study of insects, which grow in the environment full of pathogens all their lives and spread diseases between humans and animals, but themselves are not infected with pathogens. There is a class of biologically active proteins or peptides in Musca domestica bodies. Some lectins, which have been isolated and characterized from Musca domestica pupae could inhibit proliferative of tumor cells. However, the research of the lectin with immune activities was rare.In this study, an immune lectin from Musca domestica pupae (MBL-1) had been purified by affinity chromatography on ConA-Sepharose-4B and anion-exchange chromatography. MBL-1 was a glycoprotein and its molecular weight was 24 kDa which confirmed by SDS-PAGE, periodic acid-schiff stain and HPLC. Remarkable change was observed in morphology of macrophages after treated with MBL-1 through the observation of SEM. The results of AO staining and PAS staining indicated that the metabolic ability of DNA and RNA were enhanced, and the production of hepatin was increased in macrophages.The results of Immunofluorescence and Western blot showed that nuclear factor-κB (NF-κB) inhibitory κB (IκB) in endochylema was inhibited, the NF-κB in nucleus was increased and Notchl, TLR4 in cell membrane was up-regulated by MBL-1. The mRNA expressions of IL-6, IL-12 and TNF-α were up-regulated through NF-κB signal pathway.To elucidate the immunomodulatory effect of MBL-1 in vivo, the effects of MBL-1 on immune organ weight, mitogen-induced proliferation of spleen lymphocyte, phagocytosis activity of macrophages, NK cell activity, and the mRNA expression of immune factor in spleen were investigated in cyclophosphamide immunosuppressive mice. The weight index of spleen and thymus were significantly increased, the proliferation of spleen lymphocyte was enhanced, NK cell activity and phagocytosis activity of macrophages had been improved, and the mRNA expressions of IL-6, IL-12 and INF-γ in spleen were potentialized in a dose-dependent manner by MBL-1 administration. These results demonstrated that MBL-1 had a remarkable immunomodulatory effect on organism, which suggested that MBL-1 could be useful for further study as an immunomodulating agent.