Naturally occurring cytotoxic anti-tumour antibodies in sera of congenitally athymic (nude) mice

Abstract

IT has been suggested that a natural function of the immune system is the detection and elimination of nascent autochthonous tumours and that clinical tumour development reflects a failure of this immune surveillance function¹. Evidence for the involvement of thymus dependent immune processes in the prevention of spontaneous malignant disease is lacking. Thus, no significant increase in tumour incidence has been observed in either neonatally thymectomised (R. T. Prehn, personal communication) or congenitally athymic (nude) mice^2,3. If, as suggested by other studies, immune surveillance does, in fact, operate⁴, it is likely that it will involve a thymus-independent immune process. We have detected in sera of many normal mice IgM antibodies which are cytotoxic for several spontaneous and induced tumour cell lines (unpublished). The possible role of these antibodies in immune surveillance is uncertain, but if they are a manifestation of active immune surveillance, they would be expected also to occur in the sera of nude mice.