| Abstract: | The comparisons of immune responses to tumour allografts in male and female mice showed the following intersex differences: 1. Production of humoral antibodies is, in general, higher in females; since, however, the time course of titres differs for haemagglutinating and cytotoxic antibodies as well as with the sex, the titre of the same antibody may be higher in males at certain time intervals when the peak is delayed and the production in females is already declining. 2. In recipients specifically presensitized with spleen extract as well as in controls, the growth of allogeneic tumour (SaI) exhibits quantitative intersex differences being reduced in females. In the initial phase of growth, following the spleen extract, the facilitation (enhancement) of the tumour allograft is apparent olny in males, whereas in females it is delayed. 3. The facilitating effect of antibodies passively transferred from males or females corresponds mainly to the sex and strain of the recipient, only rarely to the sex of the producer. 4. In CBA strain mice, females are more resistant to the growth of SaI and also mortality from the primary tumour is lower in females; in contrast, the frequency of metastases in females is higher. 5. In the IC strain, where the sex effect on tumour growth is particularly pronounced, the consequences of castration were concordant with the inferred hormonal control of the allograft response: in males, the relatively high percentage of lethal spontaneous takes (60%) was reduced following castration (to 13%), whereas the opposite trend was observed in females, namely an increase from 0% in sham-operated controls to 23% in the castrated group. |
