Induction of cellular immunity in chimpanzees to human tumor associated antigen mucin by vaccination with MUC-1 cDNA-transfected Epstein-Barr virus-immortalized autologous B cells

Aberrant glycosylation of the mucin molecule (encoded by the gene MUC-1) on human epithelial cell tumors leads to the exposure of tumor-associated epitopes recognized by patients' antibodies and cytotoxic T cells. Consequently, these epitopes could be considered targets for immunotherapy. We designed a cellular vaccine, employing, instead of tumor cells, autologous Epstein-Barr virus (EBV)-immortalized B cells as carriers of tumor-associated mucin, to take advantage of their costimulatory molecules for T-cell activation. The vaccine was tested in chimpanzees because of the identity of the human and chimpanzee MUC-1 tandem repeat sequence. EBV-immortalized B cells derived from two chimpanzees were transfected with MUC-1 cDNA, treated with glycosylation inhibitor phenyl-N-acetyl-alpha-D-galactosaminide to expose tumor-associated epitopes, irradiated, and injected subcutaneously four times at 3-week intervals. One vaccine preparation also contained cells transduced with the interleukin 2 (IL-2) cDNA and producing low levels of IL-2. Already after the first injection we found in the peripheral blood measurable frequency of cytotoxic T-cell precursors specific for underglycosylated mucin. The highest frequency observed was after the last boost, in the lymph node draining the vaccination site. Delayed-type hypersensitivity reaction to the injected immunogens was also induced, whereas no appearance of mucin-specific antibodies was seen. Long-term observation of the animals yielded no signs of adverse effects of this immunization. Autologous antigen-presenting cells, like EBV-immortalized B cells, expressing tumor-associated antigens are potentially useful immunogens for induction of cellular anti-tumor responses in vivo

Cancer immunology

Tumorimmunolog

Editorial: Cancer Prevention: Targeting Premalignant Epithelial Neoplasms in the Era of Cancer Immunotherapy and Vaccines

Experimental cancer immunology and therap

Humoral immunity against a tandem repeat epitope of human mucin MUC-1 in sera from breast, pancreatic, and colon cancer patients

Using synthetic peptides 60,80, and 105 residues long, corresponding to 3, 4, and 5.25 tandem repeats of human mucin MUC-1 protein core, as antigens in a solid-phase enzyme-linked immunosorbent assay, we screened sera from 24 breast cancer patients, 10 colon cancer patients, and 12 pancreatic cancer patients, at various stages of disease, for the presence of mucin-specific antibodies. The 105-residue peptide was superior in allowing detection of high levels of anti-mucin antibodies in 10.9% of sera in each cancer group. Another 4.3% showed intermediate reactivity. Lower levels of detection were achieved with the 80-residue peptide, and no specific reactivity was detectable with the 60-residue peptide. Anti-mucin antibodies were previously undetectable when this assay was performed with purified whole mucin or short synthetic peptides. The presence or absence of antibody did not correlate with the levels of circulating mucin or stage of disease. One highly reactive serum sample was used to identify more precisely the epitope on the long synthetic peptide to which the reactivity was directed. The reactivity of this serum specific for the 105-residue peptide was blocked by a 9-residue peptide from the NH2-terminal region of the 20-residue tandem repeat containing the previously identified immunogenic epitope APDTRP. Another 9-residue mucin peptide, from the COOH-terminal region of the tandem repeat which does not contain the APDTRP epitope, had no effect. All the mucin-specific reactivity was found to be of the IgM isotype, indicating a helper T-cell-independent response, unusual for an antibody against a peptide epitope, but not unexpected for tandemly repeated epitopes