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Synergism between GM–CSF and IFNγ: Enhanced immunotherapy in mice with glioma
Author(s) -
Smith Karin E.,
Janelidze Shorena,
Visse Edward,
Badn Wiaam,
Salford Leif,
Siesjö Peter,
Darabi Anna
Publication year - 2006
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.22286
Subject(s) - glioma , immunotherapy , medicine , cancer research , immunization , immune system , infiltration (hvac) , immunology , active immunization , physics , thermodynamics
Glioblastoma multiforme is the most common malignant primary brain tumor and also one of the most therapy‐resistant tumors. Because of the dismal prognosis, various therapies modulating the immune system have been developed in experimental models. Previously, we have shown a 37–70% cure in a rat glioma model where rats were peripherally immunized with tumor cells producing IFNγ. On the basis of these results, we wanted to investigate whether a combination of GM–CSF and IFNγ could improve the therapeutic effect in a mouse glioma model, GL261 (GL‐wt). Three biweekly intraperitoneal (i.p.) immunizations with irradiated GM–CSF‐transduced GL261 cells (GL‐GM) induced a 44% survival in mice with intracranial glioma. While treatment of GL‐wt and GL‐GM with IFNγ in vitro induced upregulation of MHC I and MHC II on the tumor cells, it could not enhance survival after immunization. However, immunizations with GL‐GM combined with recombinant IFNγ at the immunization site synergistically enhanced survival with a cure rate of 88%. Tumors from mice receiving only 1 immunization on Day 10 after tumor inoculation were sectioned on Day 20 for analysis of leukocyte infiltration. Tumor volume was reduced and the infiltration of macrophages was denser in mice immunized with GL‐GM combined with IFNγ compared with that of both wildtype and nonimmunized mice. To our knowledge, this is the first study to demonstrate a synergy between GM–CSF and IFNγ in experimental immunotherapy of tumors, by substantially increasing survival as well as inducing a potent anti‐tumor response after only 1 postponed immunization. © 2006 Wiley‐Liss, Inc.