Effects of therapeutic treatment with the MER tubercle bacillus fraction on Rous sarcomas of chickens induced by the Rous sarcoma virus

Enhancement of avian sarcoma virus-induced tumor growth after pretreatment with BCG

“…Thus, Old et al (10) reported success with BCG in treating certain lines of chemically derived malignancies while achieving tumor growth enhancement in others. Along the same lines, Markson et al (8) have recently reported that pretreatment of chickens with MER before inoculation with RSV can exert a significant protective effect upon tumor development. These results, which clearly differ from our own (we found that MER had no effect whatever), may be due to the facts that: (i) the above authors used the Schmidt-Ruppin strain (subgroup A) of RSV, whereas we utilized both the Prague A and B77 strains of ASV; (ii) Markson et al (8) used chickens from a different source than that which supplied us; (iii) most importantly, the above authors used a dose of virus (106 focus-forming units per animal) sufficient to achieve irreversible, progressive tumor growth, a dose, incidentally, which was 1,000-fold in excess of that which we employed.…”