The effect of malaria on the growth of two syngeneic transplantable murine tumours

Abstract

Infection of BALB/c mice with Plasmodium yoelii greatly facilitated the growth of a syngeneic virus-induced transplantable lymphoma, injected subcutaneously over a range of cell doses. A similar but less marked effect could be obtained by giving 200 mg kg⁻¹ cyclophosphamide one day before tumour inoculation. By contrast, P. yoelii infection did not alter the growth of a methylcholanthrene-induced fibrosarcoma (Meth A), given sc in medium or low doses (10⁴ or 10² cells), nor did it prevent the induction of resistance against a subsequent lethal challenge with the same cell line. Following a large sc dose of 10⁶ Meth A cells, tumour growth was actually slower in mice infected with malaria than in uninfected mice.