qs-21 and Carcinoma--Small-Cell

Long chain polysialic acid (polySA) is a side chain on embryonal neural cell adhesion molecules that, in the adult, is largely restricted to small cell lung cancer (SCLC). Long chains of polySA are also expressed on group B meningococcus. In this clinical trial, we aimed to elicit an immune response against polysialic acid to target clinically inapparent residual disease in patients with SCLC who had successfully completed initial therapy.. Patients were vaccinated with either 30 micro g unmodified polySA or N-propionylated-polySA (NP-polySA), conjugated to keyhole limpet hemocyanin (KLH) and mixed with 100 micro g of immunological adjuvant QS-21 at weeks 1, 2, 3, 4, 8, and 16.. Of the 5 evaluable patients vaccinated with unmodified polySA, only 1 mounted an IgM antibody response to polySA. On the other hand, all 6 of the patients vaccinated with NP-polySA produced IgM antibodies to NP-polySA and these cross-reacted with unmodified polySA in all but 1 case. IgG antibodies to NP-polySA were observed in 5 of the patients, but these did not cross-react with polySA. The presence of IgM antibodies reactive with SCLC cell lines was confirmed in this group by flow cytometry. Complement-dependent lysis of tumor cells could not be demonstrated. However, postimmunization sera induced significant bactericidal activity against group B meningococcus when combined with rabbit complement.. Vaccination with NP-polySA-KLH, but not polySA-KLH, resulted in a consistent high titer antibody response. We are now conducting a de-escalation dosing study with NP-polySA-KLH to better assess the immunogenicity, toxicities, and optimal dose of this vaccine. We plan to incorporate this vaccine as a component of a polyvalent vaccine with GM2, fucosylated GM1, and Globo H to target SCLC.

Topics: Adjuvants, Immunologic; Aged; Antigens, Tumor-Associated, Carbohydrate; Cancer Vaccines; Carbohydrate Sequence; Carcinoma, Small Cell; Complement System Proteins; Enzyme-Linked Immunosorbent Assay; Female; Flow Cytometry; G(M1) Ganglioside; G(M2) Ganglioside; Hemocyanins; Humans; Immunoglobulin G; Immunoglobulin M; Immunotherapy; Lung Neoplasms; Male; Middle Aged; Models, Chemical; Molecular Sequence Data; Saponins; Sialic Acids; Time Factors; Vaccines, Conjugate

Fucosyl-GM1 (Fuc-GM1) [Fucalpha1 --> 2Galbeta1 --> 3GalNAcbeta1 --> 4(NeuAcalpha2-3)Galbeta1 --> 4Glcbeta1 --> O-Cer] is a small-cell-lung-cancer (SCLC)-associated ganglioside initially defined by the murine monoclonal antibody F12. On the basis of its known distribution, Fuc-GM1 is a potential target for active immunotherapy in SCLC patients. Fuc-GM1 has been extracted and purified from bovine thyroid. The immunogenicity of Fuc-GM1 was tested in mice either alone, mixed with carrier protein keyhole limpet hemocyanin (KLH) or covalently linked with KLH, plus immunological adjuvant QS-21. The Fuc-GM1-KLH conjugate plus QS-21 adjuvant was found to be optimal. It induced consistent IgM and IgG enzyme-linked immunosorbent assay (ELISA) titers against Fuc-GM1. These antibodies were strongly reactive with the strongly Fuc-GM1-positive rat hepatoma cell line H4-II-E, and they were moderately reactive with the moderately positive human SCLC cell line H146 by flow cytometry and complement-mediated lysis. Both ELISA and fluorescence-activated cell sorting (FACS) reactions were inhibited with Fuc-GM1or H4-II-E but not with the structurally related ganglioside GM1 or Fuc-GM1-negative colon cancer cell line LS-C. On the basis of these results, a vaccine comprising Fuc-GM1-KLH plus QS-21 is being prepared for testing in patients with SCLC.

Topics: Adjuvants, Immunologic; Animals; Antibodies, Neoplasm; Cancer Vaccines; Carcinoma, Small Cell; Cattle; Colonic Neoplasms; Complement System Proteins; Cytotoxicity, Immunologic; Enzyme-Linked Immunosorbent Assay; Female; G(M1) Ganglioside; Humans; Immunization; Liver Neoplasms, Experimental; Lung Neoplasms; Mice; Organ Specificity; Rats; Saponins; Tumor Cells, Cultured