Khayamabed R, et al. - In the present study, researchers incubated human processed spermatozoa with recombinant β-defensin 1 (500 ng/ml) for 1, 2 and 3 hr at 37°C under 5% CO₂ atmosphere and examined the sperm viability and motility in 59 semen samples. They conducted an analysis of semen samples such as sperm concentration, motility, viability, morphology, and semen volume according to the World Health Organization. Outcomes suggest that in the studied time intervals, the incubation of spermatozoa with recombinant β-defensin notably maintained the percentage of sperm viability and motility than processed spermatozoa incubate in the absence of β-defensin. Hence, it was concluded that sperm viability and motility in vitro conditions was maintained by the recombinant β-defensin 1 protein as an agent with antimicrobial activity.