The Journal of Immunology
Characterization of the Antibody Response against NeuGcGM3 Ganglioside Elicited in Non-Small Cell Lung Cancer Patients Immunized with an Anti-Idiotype Antibody1 Ana María Herna´ndez,2* Darie´n Toledo,* Darel Martínez,* Tania Grin˜a´n,* Victor Brito,* Amparo Macías,† Sailyn Alfonso,‡ Teresa Rondo´n,* Eduardo Sua´rez,* Ana María Va´zquez,* and Rolando Pe´rez* 1E10 mAb is an anti-Id murine mAb (Ab2 mAb) specific for an Ab1 mAb that reacts with NeuGc-containing gangliosides, sulfatides, and Ags expressed in some human tumors. In preclinical studies, this Ab2 Ab was able to mimic NeuGc-containing gangliosides only in animals lacking expression of these Ags in normal tissues. In this study, we report on the immune responses elicited in 20 non-small cell lung cancer patients treated with 1 mg of aluminum hydroxide-precipitated 1E10 mAb. In the hyperimmune sera from 16 of 20 patients, a strong specific Ab response of both IgM and IgG isotypes against NeuGcGM3 ganglioside was observed. Patient immune sera were able to induce complement-independent cell death of NeuGcGM3-expressing X63 murine myeloma target cells. Significant immunoreactivity to NeuGcGM3 was still detected after the complete abrogation of the reactivity against 1E10 mAb by the adsorption of patient sera with this Ab. We hypothesize that IdⴚAgⴙ Abs could reflect the activation of an autologous idiotypic cascade into the patients. Both IdⴙAgⴙ and IdⴚAgⴙ fractions were separated by affinity chromatography and characterized. Although IgG isotype Abs were found in both fractions, IgM isotype Abs were found only in the IdⴚAgⴙ fraction. Both IdⴙAgⴙ and IdⴚAgⴙ Abs were able to specifically recognize and induce cell death in NeuGcGM3expressing X63 myeloma target cells. Patients that developed IgG and/or IgM Abs against NeuGcGM3 showed longer median survival times. The Journal of Immunology, 2008, 181: 6625– 6634.
L
ung cancer is the leading cause of cancer-related mortality, with 1.2 million new cases worldwide diagnosed each year. The most frequent histological type is non-small cell lung cancer (NSCLC),3 which constitutes ⬃80% of the total number of new cases (1, 2). Surgery is currently the only curative treatment for NSCLC, but because the majority of the patients are diagnosed with advanced disease this is seldom an effective course of action. The majority of NSCLC patients will require systemic chemotherapy, but unfortunately the median survival time even after the best available combination of systemic active drugs is limited to ⬃8 –9 mo, and a 1-year survival rate is roughly 30 –36% (3–7). These facts underscore the urgent need to develop new therapeutic approaches for NSCLC. NeuGc-containing gangliosides are attractive targets for cancer immunotherapy as these glycolipids are not normally expressed in humans and are therefore foreign Ags, but they have been detected
*Department of Antibody Engineering and †Department of Clinical Trials, Center of Molecular Immunology, Havana, Cuba; and ‡Oncology Unit, Celestino Herna´ndez Robau Hospital, Villa Clara, Cuba Received for publication January 8, 2008. Accepted for publication August 20, 2008. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. 1
This work was supported by Recom-Bio S.L. and by the Cuban Government.
2
Address correspondence and reprint requests to Dr. Ana María Herna´ndez Va´zquez, Department of Antibody Engineering, Center of Molecular Immunology, 216 Street and 15 Avenue, Atabey, Playa, Havana 11600, Cuba. E-mail address: anita@ict.cim.sld.cu
3
Abbreviations used in this paper: NSCLC, non-small cell lung cancer; Ab2, anti-Id Ab; Ab1, idiotypic Ab; HPTLC, high performance TLC; PI, propidium iodide; CI, confidence interval. Copyright © 2008 by The American Association of Immunologists, Inc. 0022-1767/08/$2.00
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in a range of human tumors by Abs and chemical analysis (8 –12). Additionally, recent experimental data suggest that NeuGcGM3 is relevant for tumor progression (13). One strategy to generate immune responses to these glycolipids is the use of anti-Id Abs (Ab2). This approach arose from Jerne’s idiotypic network theory (14), which postulates that, due to the large potential diversity of Ig variable regions, the Id repertoire can mimic the universe of self and foreign epitopes. Thus, properly selected anti-idiotypic Abs could act as tumor-associated ganglioside surrogates. In addition to our own experience, two other anti-idiotypic mAbs mimicking gangliosides have been used in clinical trials with cancer patients, but with limited results (15, 16). We previously reported a vaccine preparation featuring a murine anti-Id mAb related to the NeuGc-containing ganglioside Ag model. This Ab2, named 1E10 (17), was generated from the immunization of BALB/c mice with P3, an idiotypic Ab (Ab1) that recognizes NeuGc-containing gangliosides, sulfated glycolipids, and Ags present in different human tumors including those from the lung, and which contains a regulatory Id according to Bona’s concept (18 –24). Preparations containing 1E10 mAb were able to induce antitumor effects against lung metastases in murine models, and phase I clinical trials have proven the safety and immunogenicity of 1E10 Id vaccination in melanoma and breast cancer patients (20, 25, 26). From these latter studies, high titer Ab responses to NeuGc-containing gangliosides were measured in the sera of cancer patients. A fraction of non-suppressible anti-NeuGc-containing ganglioside Abs was demonstrated through adsorption of these sera with 1E10 mAb, suggesting that 1E10 Id vaccination might enhance antitumor natural immune response (20, 26). Furthermore, NeuGcGM3specific IFN-␥-secreting cells were measured by ELISPOT from PBMC of 1E10-vaccinated breast cancer patients (27).