Protection by subcellular fractions prepared from lymph-nodes and spleens of specifically allergized C57 BL mice against fatal challenge with BP8 ascites tumour cells in C3H mice.

C57 B1 mice were immunized against BP8 tumour cells emulsified in Freund's complete adjuvant. Spleens and lymph-nodes from the immunized animals were homogenized and crude preparations of mitochondria, microsomes and the soluble supernatant fraction were made by centrifugation. Injected into C3H mice, all 3 fractions were able to protect against fatal challenge with BP8 tumour cells, but only animals protected by the pellet fractions were able to reject a second challenge 40 days later. Protection by the soluble supernatant was not abolished by pretreatment with ribonuclease, and it was found that the active factor could be eluted from microsomes by treatment with EDTA. For comparison purposes some results of protecting C3H mice with similar extracts made from immunized C3H mice or guinea-pigs are included.