Selection of an Inactivated Enterococcus faecium and Evaluation of its Potential as an Immunomodulator via Intravenous Injection

YouFei Selection of an Inactivated Enterococcus faecium and Evaluation of its Potential as an Immunomodulator via Intravenous Injection. Abstract Immunosuppression of livestock has become one of the key problems troubling the healthy development of the livestock industry in China. Research on the development of novel and highly effective immune enhancers to alleviate immunosuppression in livestock is important. In this study, a dexamethasone immunosuppressed mouse model was used to investigate the possibility of inactivated Enterococcus faecium by intravenous injection as an immunomodulatory agent. The effects of intravenous injection inactivated E. faecium in normal, model and immunosuppressed mice were examined using carbon clearance index, EdU marker cell assay, real-time fluorescent quantitative PCR and flow cytometry. The results showed that the inactivated E. faecium retained its intact morphology. Intravenous injection was the most potent route of administration among the different routes. The spleen, thymus and mesenteric lymph node cells of all groups of mice showed different degrees of proliferation. The cytokine expression levels, nonspecific immunity and specific immune function of normal, and DXM-immunosuppressed mice were significantly increased by intravenous injection of different doses of inactivated E. faecium . The above studies suggest that morphologically intact inactivated E. faecium can exert good immune enhancing effects by intravenous injection into mice, which has potential wide application in human medicine and veterinary clinics.