Production of tumor-specific inducer of cellular cytotoxicity by lethally irradiated mice

Antisera taken 1 or 2 days after inoculation of BALB/c mice with transplantable sarcoma cells or Moloney sarcoma virus (MSV) induce tumor-specific cell-dependent cytotoxicity in vitro. In the present experiments, lethally irradiated (“immunosup-pressed”) mice were tested for the early appearance of the serum factor responsible for this anti-serum dependent cell-mediated cytotoxicity (E-ADC). BALB/c mice were injected with MSV, syngeneic sarcoma cells or sheep red blood cells 24 h following irradiation with 900 R. Sera were obtained from MSV and tumor cell recipients 48 or 72 h later and tested for E-ADC activity. Spleen cells from SRBC recipients were tested at day 4 or 5 for ability to form direct plaques in a modified Jerne plaque assay. Although the anti-SRBC response was obliterated in the irradiated mice, the E-ADC response appeared to be unimpaired. These studies indicate that newly synthesized immunoglobulin is not required for the formation of the E-ADC factor. Production d'un inducteur tumorispecifique de la cytotoxicite cellulaire Chez les souris letalement irradiees Les antiserums preleves 1 ou 2 jours apres l'inoculation de cellules de sarcome transplantable ou de virus du sarcome de Moloney (MSV) ´ des souris BALBIc induisent in vitro une cytotoxicitd tumorispe'cifique dipendant des cellules, Dans les experiences rapportees ici, des souris letalement irradetes (“immunosup-primees”) ont ete testees en vue d'ttudier l'apparition precoce du facteur serique responsable de cette cytotoxicite ´ mediation cellulaire dependant de I'antistrum (E-ADC). Les souris BALB/c ont ete une injection de MSV, de cellules de sarcome syngenique ou derythrocytes de mouton (SRBC) 24 h apres une irradiation a 900r. Les serums ont ete preleves 48 ou 72 h apres I'administration de MSV ou de cellules tumorales, puis on a etudie leur activit´ E-ADC. Les cellules spleniques des receveurs de SRBC ont ete testes au jour 4 ou 5 du point de vue de leur aptitude h former des plaques directes dans une Ppreuve de Jerne modifiie. La reponse anti-SRBC a disparu chez les souris irradides, tandis que la reponse E-A DC semble ne pas avoir ete modifee. Ces etudes indiquent qu'une immunoglobuline nuvellement syntheisee neest pas ntcessaire pour la formation du facteur E-ADC.