The Antibacterial Activity Of Genetic Engineering Tachyplesin Ⅰ To Staphylococcus Aureus In Vitro/Vivo And Mechanism Of Enhancing Non-specific Immunity In Mice

The antibacterial activity of Genetic engineering Tachyplesin I to Staphylococcusaureus in vitro/vivo and mechanism of enhanced non-specific immunity in miceStaphylococcus aureus (S. aureus) is a common and dangerous pathogen that underliesvarious infectious diseases, including skin abscesses, wound infections, endocarditis, osteomyelitis,pneumonia, and toxic shock syndrome. Treatment of these infections has become ever moredifficult due to the emergence of multidrug-resistant strains, especially Methicillin-resistant S.aureus (MRSA), raising serious concerns within the medical community. Therefore, there is anurgent need for novel therapeutic agents directed against this formidable pathogen. Antimicrobialpeptides is an important area of novel therapeutic agents. Tachyplesin is one member ofantimicrobial peptides. Our goup has studied the Antimicrobial peptides Tachyplesin I for a longtime. In this study, Tchyplesin I has been researched to detect the ability of treating S. aureusinfection.First, the Tachyplesin I was expressed and purified， the minimal inhabit concentration (MIC)of Tachyplesin I against S. aureus strain ATCC29213is （3.26±0.76）μg/mL and thesub-inhibitory concentration is0.815μg/mL. The ability of Tachyplesin I to modify the immunefunction of the mice has been studied, the resultindicated that Tachyplesin I eliminated S. aureusin vivo and mitigated the damage in the lung of mice, exhibited a good therapeutic effect.Additionally, the β-defensins and thymosin were increased in mice after treated with Tachyplesin I.Simultaneously, the expression of TNF-ɑ, IL-4and other inflammatory factors were reduced. TheTachyplesin I also regulated the phagocytosis of macrophage in mice. Ten days after usingTachyplesin I, the weight and spleen index of mice were detected, compared with contol group,the weight of the mice in the Tachyplesin I groups were raised significantly (P<0.05),; thephagocytosis index and clearance index of macrophage were improved significantly. The resultsof ELISA and RT-PCR showed that the content of β-defensins and thymosin the in every tissuesand serum were raised after being treated with Tachyplesin I, which indicated that the defensecapabilities of mice have been improved.This study provided reference and theoretical basis for the clinical applying of Tachyplesin Ias ecological agents.