It has been conclusively shown that immunization of female mice with spermatozoa can significantly decrease their fertility (McLaren, 1964, 1966; Edwards, 1964; Bell, 1969; Bell & McLaren, 1970). All of the work by McLaren and Bell (McLaren, 1964, 1966; Bell, 1969; Bell & McLaren, 1970) has involved very extensive courses of immunization: from twenty-one to twenty-four injections of 6 to 15 × 106 spermatozoa or fractions thereof. Edwards (1964) used shorter and more varied immunization schedules, with three to eleven booster injections in different individuals of one experimental group, and found a smaller effect on the number of eggs fertilized than McLaren and Bell found on the number of liveborn offspring (McLaren, 1964, 1966; Bell, 1969; Bell & McLaren, 1970). However, none of the female mice in Edwards experiments received fewer than
R. P. ERICKSON
Although a variety of methods have been used for measuring antibodies to spermatozoa, many have only been qualitative, for instance immunofluorescence. The most commonly used technique, sperm agglutination, would not measure non-precipitating antibodies. The more recently developed cytotoxic tests (Hamerlynck & Rümke, 1968) also detect a limited spectrum of antibody types. Binding tests which measure antibody absorbed to a target cell have rarely been used in studies of sperm antigens. Noyes (1969) used a direct binding test for human anti-sperm antibodies which involved labelling a patient's sera with131I. In the work described here, an isotopic antiglobulin technique (Harder & McKhann, 1968; Bomford, Breitner, Mitchison, Negroni & Raff, 1969; Sparks, Ting, Hammond & Herberman, 1969) has been adapted for use with mouse spermatozoa. This is an indirect or `sandwich' technique which utilizes125I-rabbit-anti-mouse-γ-globulin to detect mouse anti-mouse-spermatozoa antibodies bound to spermatozoa. The one radioactive reagent
R. P. ERICKSON and HALINA KRZANOWSKA
Braden (1958) demonstrated that inbred strains of mice differ significantly in the proportion of eggs in which the zona pellucida is penetrated by more than one spermatozoon (supplementary spermatozoa). This difference was shown to be dependent on the strain of the male while differences in the rate of dissolution of the cumulus oophorus were dependent on the strain of the female.
These and other properties have been studied in great detail in the low fertility strain KE, maintained by one of us (H.K.), and the results have been compared with those for some other inbred strains of mice. In the KE strain, 30% of ova remain unfertilized (Krzanowska, 1960) and there is delayed penetration of the vitellus (Krzanowska, 1964).
J. M. Kramer and R. P. Erickson
Summary. Cells were labelled by intratesticular injection of [35S]methionine. After 14–16 h the relative rates of incorporation of label in spermatocytes, early spermatids and late spermatids were 10:2:1 respectively. Approximately 15% of the soluble (100 000 g supernatant) and 20% of the particulate proteins solubilized by NP-40 (from the 100 000 g pellet) that were detectable on two-dimensional gels showed stage-specific synthesis. A large number of proteins were detectable only in post-meiotic cells and may be valuable for studying the control of gene expression in haploid cells.
H. SPIELMANN, R. P. ERICKSON and C. J. EPSTEIN
Lactate dehydrogenase and glucose-6-phosphate dehydrogenase in Day-1 and Day-4 preimplantation mouse embryos was assayed by immunotitration. For both enzymes, immunoreactive protein was found to decrease in parallel with enzyme activity, indicating that loss of activity is probably the result of enzyme degradation. The identification of embryonic lactate dehydrogenase as isoenzyme LDH-1 and of glucose-6-phosphate dehydrogenase as the form found in red cells is corroborated by the immunological data.