Isolation by using albumin columns of a cohort of fast-swimming human spermatozoa

Unwashed human spermatozoa enter columns of 20% albumin in cohorts and not in a continuous stream. Using normospermic ejaculates, a single cohort, representing approximately 10% of the total number of spermatozoa added, appeared within 1 h of addition. In contrast, when ejaculates from asthenozoospermic men were tested using the same incubation period (1 h), the cohorts contained less than 5% of the total. Exposure of ejaculates to 2-deoxyadenosine, a potent stimulator of sperm motility, doubled the number of spermatozoa present in the cohort, but not the average velocity of the group. We suggest that spermatozoa also enter the cervical mucus and pass through the female reproductive tract in cohesive groups.