Synthesis of sialyl Lewis(a) (sLe(a), CA19-9) and construction of an immunogenic sLe(a) vaccine Journal Article

Authors: Ragupathi, G.; Damani, P.; Srivastava, G.; Srivastava, O.; Sucheck, S. J.; Ichikawa, Y.; Livingston, P. O.
Article Title: Synthesis of sialyl Lewis(a) (sLe(a), CA19-9) and construction of an immunogenic sLe(a) vaccine
Abstract: Sialyl Lewis(a) (sLe(a)), also termed CA19-9 antigen, is recognized by murine mAb19-9 and is expressed on the cancer cell surface as a glycolipid and as an O-linked glycoprotein. It is highly expressed in a variety of gastrointestinal epithelial malignancies including colon cancer and pancreatic cancer, and in breast cancer and small cell lung cancer, but has a limited expression on normal tissues. sLe(a) is known to be the ligand for endothelial cell selectins suggesting a role for sLe(a) in cancer metastases and adhesion. For these reasons, sLe(a) may be a good target for antibody mediated immunotherapy including monoclonal antibodies and tumor vaccines. However, sLe(a) is structurally similar to sLe(x) and other blood group related carbohydrates which are widely expressed on polymorphonucleocytes and other circulating cells, raising concern that immunization against sLe(a) will induce antibodies reactive with these more widely expressed autoantigens. We have shown previously both in mice and in patients that conjugation of a variety of carbohydrate cancer antigen to keyhole limpet hemocyanin (KLH) and administration of this conjugate mixed with saponin adjuvants QS-21 or GPI-0100 are the most effective methods for induction of antibodies against these cancer antigens. We describe here for the first time the total synthesis of pentenyl glycoside of sLe(a) hexasaccharide and its conjugation to KLH to construct a sLe(a)-KLH conjugate. Groups of five mice were vaccinated subcutaneously four times over 6 weeks. Sera were tested against sLe(a)-HSA by ELISA and against sLe(a) positive human cell lines adenocarcinoma SW626 and small cell lung cancer (SCLC) DMS79 by FACS. As expected, mice immunized with unconjugated sLe(a) plus GPI-0100 or unconjugated sLe(a) mixed with KLH plus GPI-0100 failed to produce antibodies against sLe(a). However, mice immunized with sLe(a)-KLH conjugate without GPI-0100 produced low levels of antibodies and mice immunized with sLe(a)-KLH plus GPI-0100 produced significantly higher titer IgG and IgM antibodies against sLe(a) by ELISA. These antibodies were highly reactive by FACS and mediated potent complement mediated cytotoxicity against sLe(a) positive SW626 and DMS79 cells. They showed no detectable cross reactivity against a series of other blood group-related antigens, including Le(y), Le(x), and sLe(x) by dot blot immune staining. This vaccine is ready for testing as an active immunotherapy for treating sLe(a) positive cancer in clinical settings. © 2009 Springer-Verlag.
Keywords: controlled study; unclassified drug; human cell; nonhuman; flow cytometry; adenocarcinoma; mouse; animals; mice; lung neoplasms; ca 19-9 antigen; animal experiment; animal model; cancer cell culture; drug synthesis; mice, inbred c57bl; immunoglobulin g; cancer vaccine; cancer vaccines; immunogenicity; immunological adjuvant; enzyme-linked immunosorbent assay; cross reaction; immunoglobulin g antibody; antibody titer; complement dependent cytotoxicity; keyhole limpet hemocyanin; ca19-9; carbohydrate conjugate vaccine; sialyl lewis<sup>a</sup>; gpi 0100; human serum albumin; immunoglobulin m antibody; sialyl lewis a antigen keyhole limpet hemocyanin conjugate; hemocyanin; immunoglobulin m; lewis blood-group system; saponins; small cell lung carcinoma; vaccines, conjugate
Journal Title: Cancer Immunology, Immunotherapy
Volume: 58
Issue: 9
ISSN: 0340-7004
Publisher: Springer  
Date Published: 2009-09-01
Start Page: 1397
End Page: 1405
Language: English
DOI: 10.1007/s00262-008-0654-7
PUBMED: 19190907
PROVIDER: scopus
PMCID: PMC2828770
Notes: --- - "Cited By (since 1996): 2" - "Export Date: 30 November 2010" - "CODEN: CIIMD" - "Source: Scopus"
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MSK Authors
  1. Govindaswami Ragupathi
    133 Ragupathi
  2. Payal Damani
    9 Damani