✓ The introduction of active specific immunotherapy as an adjunct to conventional therapy of the brain-tumor patient creates the risk of the concomitant induction of experimental allergic encephalomyelitis (EAE). The lack of resolution concerning the total group of central nervous system (CNS) antigens which may be encephalitogenic, and the lack of definition of the necessary conditions for the induction of an anti-CNS myelin response complicate the design of an immunotherapeutic regimen for brain-tumor patients. We report here the ready induction of EAE in four of four guinea pigs and both of two nonhuman primates (Macaca fascicularis) with human glioblastoma multiforme (GBM) tissue injected with either complete or incomplete Freund's adjuvant (CFA, IFA). Immunization protocols utilizing encephalitogenic GBM tissue and adjuvant which did not result in EAE induction were established in both of two macaques, and the production of significant levels of antibodies specifically reactive with immunizing GBM-derived cultured cell lines in all of 12 macaques without EAE induction was demonstrated. As the lower detection limit of the sodium dodecyl sulfate-polyacrylimide gel electrophoresis (SDS-PAGE) assay for human myelin basic protein (HBP) was 0.6 µg HBP/gel, and an extract prepared from WR-GBM tumor tissue contained less than 0.6 µg of detectable HBP/25 µg of pH 3 extractable protein, and as 100 to 1000 µg of purified human basic protein (HBP) failed to induce EAE in three of three macaques, it was hypothesized that 1) GBM tissue may act as an adjuvant and markedly lower myelin basic protein (MBP) threshold doses for EAE induction, that 2) MBP encephalitogenic fragments capable of EAE induction may be present in GBM tissue but difficult to quantitate in precipitates by in vitro methods, or that 3) secondary encephalitogenic antigens unrelated to MBP may be present in GBM tissue. The threat of EAE induction and the potential difficulty of its detection in the deteriorating brain-tumor patient receiving active specific immunotherapy warrants a biological screen in immunizing CNS material in experimental animals prior to administration to patients in immunotherapy protocols.
Darell D. Bigner, Olin M. Pitts and Carol J. Wikstrand
Part 8: Serological responses to active immunization of patients with anaplastic gliomas
M. Stephen Mahaley Jr., G. Yancey Gillespie, Ritchie P. Gillespie, Pamela J. Watkins, Darell D. Bigner, Carol J. Wikstrand, J. Marilyn MacQueen and Fred Sanfilippo
✓ Serial serological studies were carried out on 19 of 20 patients with malignant gliomas who were actively immunized with one of two human glioma tissue culture cell lines (D-54MG or U-251MG). Most patients mounted a significant serum reaction to histocompatibility antigens (HLA's), as well as an antibody response to fetal bovine serum (FBS) which was added to the glioma-cell inoculum. These two sources of antibody accounted for greater than 90% of the antibody induced by these inoculations. Two patients continued to have significant amounts of binding antibody to the original immunizing cell line following exhaustive absorptions of FBS and HLA antibodies. One of these two had all remaining significant antibody removed by further absorption of the serum against the 2-T osteogenic sarcoma tissue culture cell line known to possess antigens cross-reactive with human gliomas. One single patient continued to show significant antibody binding to the original glioma cell line following absorption against FBS, human platelets, and the 2-T cell line, and therefore seems to have produced glioma-distinctive antibodies in response to immunization. The antibody preparation from this patient was also cytotoxic against the original glioma cell line, as well as another recently cultured human glioblastoma cell line. The significance of these serological studies is discussed as it relates to immunological responses patients with gliomas may make to active immunization.