母乳喂养可有效预防感染，是新生儿最理想的食物。β-casein 65是我们通过串联质谱技术发现的、显著高表达于早产母亲初乳中、功能未知的内源性多肽。实验证实β-casein 65对新生儿感染常见致病菌S. aureus、K. pneumoniae、E. coli均具有杀伤作用；生物信息学分析和预实验提示β-casein 65可破坏细胞膜、结合核内物质发挥作用。本研究拟进一步论证β-casein 65抗新生儿常见致病菌功能并探索其杀伤机制；在体评估β-casein 65对大鼠NEC、肺炎动物模型的治疗作用；初步建立β-casein 65临床应用前大规模制备方法。β-casein 65功能未见报道，若研究成功，无疑具有巨大的潜在临床应用价值。

Breast milk which has an effective function on preventing infection is the ideal food for newborns. β-casein65 is a novel endogenous peptides found in preterm milk by Liquid chromatography–mass spectrometry/mass spectrometry (LC-MS/MS) technique. Experiments confirmed that β-casein65 has strong antibacterial activity. Further study found that β-casein65 has cell killing and injury effect on common newborn infection bacteria, e.g. S. aureus, K. pneumoniae and E. coli. Bioinformatics analysis and preliminary experiments suggested that β-casein 65 may damage cell membranes and combine with nuclear material. This study was to investigate the antibacterial activity and mechanism of β-casein 65 against common bacterial infection in premature children on this basis, to assess the therapeutic effect of β-casein65 in vivo through NEC and pneumonia rat model, and to establish the method of β-casein65 large-scale preparation before clinical application. β-casein 65 function have not been reported. If succeed β-casein65 will undoubtedly have a huge potential clinical value.