[Role of complement for the sensitivity of sperm immobilization test (author's transl)]

For detecting the sperm immobilizing antibody in the sera of infertile women with unknown cause, Isojima's sperm immobilization test was widely used, but there was great difference on the percentage of positive results among several laboratories. For analysis of factors influencing the sensitivity of the test, source and amount of complement were studied, and the following results were obtained. 1. Guinea pig serum which contained more than 200 CH50 as hemolytic titer was best for this test. 2. Rat and rabbit sera which contained much lower CH50 than guinea pig indicated relatively good sensitivity for the test. 3. Human serum which contained 34.9 CH50/ml and mouse serum which contained less than 5 CH50/ml, both could not work on sperm immobilization test. The human serum (AB) which was concentrated to the level of guinea pigs serum as CH50 did not work well on sperm immobilization test as guinea pig serum. 4. When the complement from same source was used, the positive correlation between CH50 (hemolytic titer) and 50% sperm immobilization titer (SI50) was present, but if the complement source was different, there was no correlation between CH50 and SI50. 5. It was proved that more than 10 CH50 of guinea pig serum was necessary for sperm immobilization test to obtain the most sensitive results.