Amino acid-modified calcitonin immunization induces tumor epitope-specific immunity in a transgenic mouse model for medullary thyroid carcinoma.
Up to now, no relevant tumor antigen has been identified in medullary thyroid carcinoma (MTC). The aim of the present study was to prove the concept of an immunization with an amino acid-modified calcitonin (CT) for the treatment of MTC in a transgenic mouse model. Amino acid-modified (human) CT has been chosen for vaccination because of its higher binding affinity to the murine H2-Kb-MHC molecule. Mice were immunized over 6 months with monthly injections of amino acid-modified CT-pulsed dendritic cells. For enumeration of tumor epitope-specific CD8+ cytotoxic T cells, tetramer analyses were performed. CT peptide-treated mice revealed a mean 0.73 +/- 0.45 and 0.91 +/- 0.59% positive cells, depending on the two tetramers tested, whereas no increase was seen in control protein-immunized mice (0.08-0.12% tetramer-positive cells). Importantly, the subset of CT-specific CD8+ T cells also showed a high expression of interferon-gamma. In line with these results, CT-immunized mice also showed an intratumor infiltration with CD8+ T lymphocytes. Importantly, we also found a diminished tumor outgrowth of -57% and a decrease of the serum CT levels (2.0 +/- 0.1 pg/ml) compared with control protein-immunized Ret/Cal mice (3.0 +/- 0.4 pg/ml). In summary, we show that amino acid-modified CT is recognized from the immune system leading to a specific antitumor immune response and a diminished tumor outgrowth in transgenic MTC mice. The results are of potential importance because they might be applicable to patients with metastatic spread of a MTC.
Wuttke
Margret
M
Endocrine Cancer Center, Department of Endocrinology, Diabetology and Rheumatology, University Hospital Duesseldorf, 40225 Duesseldorf, Germany.
Papewalis
Claudia
C
Meyer
Yvonne
Y
Kessler
Caroline
C
Jacobs
Benedikt
B
Willenberg
Holger S
HS
Schinner
Sven
S
Kouatchoua
Christine
C
Baehring
Thomas
T
Scherbaum
Werner A
WA
Schott
Matthias
M
D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D000918:Antibody Specificity; D000951:Antigens, Neoplasm / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002116:Calcitonin / Q000737:chemistry / Q000276:immunology*; D018276:Carcinoma, Medullary / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D004195:Disease Models, Animal; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D007114:Immunization / Q000379:methods; D016233:Immunotherapy, Active; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D020556:Neutrophil Infiltration / Q000276:immunology; D013964:Thyroid Neoplasms / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D047368:Tumor Burden
D000596:Amino Acids; D000951:Antigens, Neoplasm; D018984:Epitopes, T-Lymphocyte; D002116:Calcitonin