Effector molecule of the innate immune system that acts via antibiotic-like properties against a broad array of infectious agents including bacteria, fungi, and viruses (PubMed:15616305, PubMed:15772169, PubMed:17142766). Possesses the ability to neutralize bacterial toxins such as B.anthracis lethal factor, Clostridium difficile cytotoxin B as well as leukocidin produced by Staphylococcus aureus (PubMed:15772169, PubMed:18435932, PubMed:25963798). Also blocks herpes simplex virus infection by interacting with envelope glycoprotein B and thus preventing its binding to heparan sulfate, the receptor for attachment (PubMed:17142766). {ECO:0000269|PubMed:15616305, ECO:0000269|PubMed:15772169, ECO:0000269|PubMed:15894545, ECO:0000269|PubMed:17142766, ECO:0000269|PubMed:17452329, ECO:0000269|PubMed:18435932, ECO:0000269|PubMed:2006422, ECO:0000269|PubMed:25963798}. This is the function of ENSG00000239839 (DEFA3, defensin alpha 3).