Journal of immunotherapy with emphasis on tumor immunology : official journal of the Society for Biological Therapy最新文献

Previously we have demonstrated that two doses of a cytotoxic T lymphocyte (CTL) epitope-based peptide vaccine of human papillomavirus type 16 (HPV 16) E7 aa 49-57 elicit protection against outgrowth of HPV 16-transformed tumor cells (C3 cells) in B6 mice. Incomplete Freund's adjuvant (IFA), as a carrier, was used to induce this response. To avoid side effects caused by the use of external adjuvants, we have now investigated the effectiveness of highly purified spleen dendritic cells (DC) that efficiently induce primary peptide-specific CTL responses in vitro, as physiological carriers for the HPV 16 E7(49-57) peptide-based vaccine. This is the first report demonstrating that mice immunized once i.v. with syngeneic spleen DCs pulsed with the HPV 16 E7(49-57) peptide in vitro were protected against the outgrowth of C3 tumor cells. In comparison, a single injection of the HPV 16 E7(49-57) peptide in IFA s.c. also resulted in effective induction of tumor-specific immunity in vivo. In both immunization protocols, protective tumor-specific immunity was mediated by CTL that recognized HPV 16 E7(49-57) peptide-pulsed target cells, as well as C3 cells in vitro. Peptide affinity of the CTL induced by both protocols was similar. Thus under the conditions tested, a single injection of spleen DCs pulsed with a CTL epitope-based peptide in vitro elicited tumor-antigen-specific CTL in vivo, which protected mice against a subsequent tumor inoculation. This result indicates that spleen DCs pulsed with a CTL epitope can effectively serve as a tumor-specific vaccine.

We have developed and characterized a murine monoclonal antiidiotype (Id) antibody (Ab2), designated 3H1 (IgG1-k) that mimics human carcinoembryonic antigen (CEA). 3H1 was raised against an anti-CEA monoclonal antibody (mAb) 8019 (Ab1) that recognizes a distinct and specific epitope of the 180,000 MW CEA. 3H1 induced specific anti-CEA immune responses in mice and rabbits. In this preclinical study, cynomolgus monkeys (Macaca fascicularis) were immunized with aluminum hydroxide-precipitated 3H1 and tested for the induction of anti-CEA antibodies. Monkeys were injected with 2 mg of 3H1, intracutaneously, four times biweekly. All monkeys developed specific anti-anti-Id (Ab3) responses that were capable of inhibiting binding of the immunizing 3H1 (Ab2) to 8019 (Ab1) and vice versa. Furthermore, immune sera from monkeys contained Ab3 (Abl') antibody that bound to CEA-positive colon carcinoma cell lines but not to CEA-negative MOLT-4 or melanoma cell lines. Also, the Ab3 reacted with purified CEA and competed with Ab1 (8019) for binding to CEA positive LS174-T cells, suggesting that Ab1 and Ab3 may bind to the same epitope. In addition, affinity-purified Ab3 from monkey sera immunoprecipitated the same 180,000 MW CEA as Ab1 8019 and showed an identical pattern as the Ab1 on colon carcinoma specimens by immunoperoxidase staining. The induction of anti-tumor antibodies in monkeys did not cause any apparent side effects. These data suggest that internal image anti-Id can induce tumor-specific humoral immune responses in nonhuman primates and can serve as potential network antigen for triggering active anti-CEA antibodies in colorectal cancer patients.

Cardiac toxicity and hemodynamic alterations are frequently associated with high-dose interleukin-2 (IL-2) immunotherapy in cancer patients. Serious cardiac events including myocardial infarction, ischemia, and noninfectious myocarditis have been observed. We document two cases of unusually severe but reversible cardiac abnormalities related to IL-2 therapy: one patient with a profound form of global myocardial hypocontractility and a second patient with regional aneurysmal and dyskinetic changes of the left ventricle. These cases exhibit unique features not previously described in IL-2-treated patients. The possible pathophysiologic mechanisms underlying these global and regional forms of cardiomyopathy, including the production of secondary-messenger molecules such as nitric oxide and myocardial stunning, are discussed. Both patients remain disease free of their cancer (> 3 years since completing therapy), are without residual cardiac dysfunction or recurrent related symptoms, and have not experienced any additional cardiac events. The report demonstrates the complexity of the cardiac toxicities associated with IL-2-based immunotherapy and recognizes a need for treating physicians to be familiar with their management.

We report one patient with paralysis of the right upper extremity, bilateral cerebellar syndrome, and cognitive changes after treatment with interleukin-2 for metastatic renal cell carcinoma. Focal neurologic disturbances were associated with multiple images of cerebral infarcts but also with extraneurologic signs and autoantibodies. We suggest that this is a case of cerebral vasculitis with an autoimmune mechanism triggered by interleukin-2 therapy.

In the development of cytotoxic T lymphocyte (CTL)-mediated immunotherapy, the identification of CTL epitopes is of crucial importance. Binding of a peptide to major histocompatibility complex (MHC) class I molecules is one of the prerequisites for its function as a CTL epitope. We describe the technique, validation, and application of a simple cellular assay, intended for the screening of peptides for binding, that can be applied to any human leukocyte antigen (HLA) allele. Reconstitution of peptides in MHC class I molecules after elution by acid treatment was previously shown to be possible in specially engineered cell lines expressing only one type of MHC class I, and was applied for the HLA-A*0201 allele. We now report the optimal conditions for application of this type of binding assay to the HLA-A*0301 allele. The adaptations that were necessary to make the technique operational for HLA-A*0301 are shown in detail. These consisted of lowering the pH during acid treatment to 2.9 and lengthening the duration of elution to 90 s. Furthermore, immediate aspiration of eluted peptides appeared to be essential for this allele. We found also that the use of Epstein-Barr virus (EBV)-transformed B cell lines (B-LCL) yields results similar to those of the use of cell lines expressing only one specific MHC class I allele. Homozygosity for the desired HLA allele improves the sensitivity of the assay, but heterozygous cells can also be employed. Finally, we applied this technique to a search for HLA-A*0301 binding peptides derived from carcinoembryonic antigen (CEA). Of a set of 34 CEA-specific peptides that fit with a specified HLA-A*0301-binding motif, we identified a set of six peptides with high binding affinity to this allele. These peptides can be regarded as potential CTL epitopes.