[Lymphocyte reactivity of tumor-bearing mice to a 3M KCl extract of fetal mouse tissue: removal of diffusion chambers containing tumor cells reverses the reactivity].

Sensitization of lymphocytes to 3M KCl fetal extracts was shown by the MEM test after diffusion chambers containing tumor cells have been implanted into mice. Lymphocyte reactivity was still present 2, 4 and 6 weeks after removal of the chambers. When tested after 9 and 12 weeks the sensitization was no longer detectable. This results show the reversibility of sensitization after complete removal of tumor cells.