BCG immunotherapy of rat tumours in athymic nude mice

Abstract

CONSIDERABLE emphasis is now being placed on the use of bacterial adjuvants such as bacillus Calmette Guerin (BCG) and Corynebacterium parvum for the immunotherapy of malignant disease. While general immunostimulation by these adjuvants produces a therapeutic response against some but not all experimental animal tumours^1,2, there is evidence to suggest that a more effective suppression of tumour growth can be achieved by contacting the adjuvant with the tumour^3,4. Tumour cells injected into compatible hosts in admixture with BCG often do not produce progressively growing tumours⁴ and in some cases regression of established tumour grafts can be produced by intralesional injections of BCG (ref. 3) or C. parvum⁵. Clinically this is akin to the observation that cutaneous melanoma nodules may regress following intralesional injection of BCG (refs 6 and 7). Adjuvant contact immunotherapy has also been used in experimental animal studies to suppress growth of tumours developing in pulmonary or pleural sites, which are models for the treatment of metastatic disease^8–10.