Heterotransplantability testing in nude mice of candidate cell for vaccine production

Regulations for vaccine production require that candidate cells of human origin must be controlled for the absence of tumourigenic activities by heterotransplantability in animals. Usually, the test was done in the cheek-pouch of three week old hamsters, but this method presents disadvantages; long observation period (3 months) and a high rate of intercurrent diseases. The authors describe their experience using nude mice pretreated with antithymocyte serum of rabbit origin; the observation period is reduced to three weeks, the test is easy to perform and to read.