抗菌肽在自然界生物体广泛存在，以其分子量小、抗菌谱广、热稳定性好、不易产生耐药及增强动物天然免疫力等优势，被国际上公认为是当前抗生素最理想的替代品。近年来，抗菌肽的研究虽然取得了一定的进展，但其对动物体增强免疫能力的分子作用机制还不十分明确，影响了抗菌肽的综合开发利用。本项目在前期研究基础上，以牛源抗菌肽类似物JH-3为研究对象，通过细胞趋化、吞噬、胞内杀菌等试验，以阐明JH-3对巨噬细胞生物功能影响。通过检测巨噬细胞对脂多糖（LPS）结合、胞内活性杀菌分子含量及其信号传导通路，以证明JH-3增强细胞吞噬功能的分子机制。最后，通过动物感染试验，来评价JH-3在多重耐药鼠伤寒沙门氏菌及其脂多糖（LPS）缺失突变株对小鼠侵袭的作用。本课题将阐明JH-3增强动物天然免疫能力的分子机制，为未来安全、高效抗菌肽的临床推广应用提供必要的理论依据。

Antimicrobial peptides widely exist in organism in nature, and are regarded presently as the most ideal substitute of antibiotics, with its small molecular weight, broad antibacterial spectrum, good thermal stability, non-producing resistance, enhancing animal natural immunity and other advantages. In recent years, the study of antimicrobial peptides has made some progress, but its enhancing immune ability is not very clear, which affect their comprehensive development and utilization. On the basis of preliminary study, using antimicrobial peptide analogue JH-3 from bovine as the object, its effect on the innate immune cells will be study by chemotaxis assay, phayocytosis assay and killing bacteria in cell. In addition, the molecular mechanism of JH-3 enhancing cell phagocytosis will be clarified by testing the binding between macrophage and lipopolysaccharide (LPS), the content of active molecules killing bacteria and its signal transmission. Finally, the role of JH-3 in protecting the mice from invading by a multidrug resistance Salmonella enterica serovar Typhimurium and its mutants with the deficient of LPS will also be detected. In summary, the results will provide a necessary theoretical basis for further development of safe and high efficiency of new antibacterial peptide preparation.