Failure to relate the anti-tumour action of cyclophosphamide with the immunogenicity of two murine fibrosarcomas
✍ Scribed by R. Evans
- Publisher
- John Wiley and Sons
- Year
- 1978
- Tongue
- French
- Weight
- 502 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0020-7136
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✦ Synopsis
Abstract
A single intraperitoneal injection of cyclophos‐phamide (CY) had a stronger anti‐tumour effect upon two syngeneic mouse fibrosarcomas when given within a few days of tumour implantation than when given 7‐20 days after. CY was more active against the fast‐growing, relatively non‐immunogenic CBA fibrosarcoma, FS13, inducing a higher proportion of permanent regressions, than the slower‐growing, highly immunogenic C57BL fibrosarcoma, FS6, at all comparable stages of tumour growth. Whole‐body irradiation, which suppressed concomitant immunity in FS6‐tumour‐bearing mice, had no effect on the anti‐tumour action of CY. A study of the cellular composition of the tumour masses over a 4‐day period immediately after CY injection showed that there was a decrease in total cell yields, involving mainly a decrease in neoplastic cells, although normal cells, Fc‐receptor‐positive and ‐negative, were also affected to a lesser degree. The overall findings indicated a lack of correlation between the anti‐tumour effects of CY and tumour immunogenicity. Moreover, it was apparent that the anti‐tumour action of CY was mediated by a direct effect of its metabolites on neoplastic cells rather than by host anti‐tumour effector mechanisms.