The effect of vitamin B-6 deficiency on host susceptibility to Moloney sarcoma virus-induced tumor growth in mice.

The effect of vitamin B-6 deficiency on in vivo host susceptibility to primary Moloney sarcoma virus (MSV)-induced tumor growth and to secondary challenge with MSB sarcoma cells was examined in mice. Female C57BL/6 mice, 6 weeks of age, were fed 20% casein diets with pyridoxine (PN) added at 1, 0.5, 0.1 or 0 mg/kg diet for 21 weeks. After 4 weeks of dietary treatment the mice were challenged with MSV. Vitamin B-6 deficiency resulted in an enhancement of tumor susceptibility as well as an increase in tumor size and regression time. The animals resistant to both MSV and MSV-transformed tumor cells ( MSB ) challenge showed splenic tumor development at necropsy 51 days after MSB challenge. Total incidence of MSV/ MSB /splenic tumors was 2/11, 2/11, 4/10 and 8/11 in animals fed PN 1, 0.5, 0.1 and 0 diets, respectively. Since MSV-induced tumors regressed spontaneously in immunocompetent hosts, the increased susceptibility to MSV oncogenesis in vitamin B-6-deficient animals suggests that reactivity of T cells and/or other effector cells is impaired in vitamin B-6-deficient animals suggests that reactivity of T cells and/or other effector cells is impaired in vitamin B-6 adequacy.