Rabbit and bull spermatozoa were observed undergoing phagocytosis by polymorphonuclear leucocytes after being injected into ligated uteri of oestrous and luteal phase rabbits. An interaction between the species of spermatozoa injected and the reproductive phase of the rabbit occurred in the number of recovered spermatozoa.
Killing the bull spermatozoa prior to injection decreased the recovery rate significantly while killing the rabbit spermatozoa had no significant effect.
Treating either bull or rabbit spermatozoa with uterine exudates induced by bull spermatozoa decreased significantly the recovery rates from oestrous rabbits as compared to treatment with saline solution or exudates induced by rabbit spermatozoa.
In leucopenic rabbits, differences in recovery rates due to species of spermatozoa injected and reproductive phase of the rabbit were not evident. Approximately 75 to 80% of the spermatozoa injected were recovered compared to less than 20% for the controls.
In none of the experiments did the number of recovered leucocytes vary with the different treatments, except after the induction of leucopenia.