Vectors encoding carcinoembryonic antigen fused to the B subunit of heat-labile enterotoxin elicit antigen-specific immune responses and antitumor effects

Vaccine. 2007 Dec 21;26(1):47-58. doi: 10.1016/j.vaccine.2007.10.060. Epub 2007 Nov 20.


Vectors encoding CEA fused to the A (CEA-LTA) or B (CEA-LTB) subunits of the heat-labile enterotoxin were constructed and their immunogenicity was compared. The CEA-LTB fusion was shown to elicit a greater CEA-specific antibody and CD8+ T-cell response. Plasmid DNA and Adenovirus vectors encoding CEA-LTB proved to be immunogenic in CEA transgenic ( mice. mice immunized with repeated injections of plasmid pV1J/CEA-LTB followed by Ad/CEA-LTB were protected from tumor growth, but the adjuvant activity of the LTB protein was lost upon mutation of the LTB sequence. Depletion of T-regulatory cells increased the vaccine antitumor effect. Tumor protection was abrogated if the NK or CD8+ cell population was depleted before tumor challenge. Passive transfer studies demonstrated that CD8+ T cells contribute to the antitumor effect, thus suggesting that a genetic vaccine based on plasmid DNA and adenoviral vectors encoding CEA-LTB augments CEA-specific immune responses and significantly protects from tumor development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / genetics*
  • Animals
  • Bacterial Toxins / genetics*
  • Bacterial Toxins / immunology
  • CD8-Positive T-Lymphocytes / immunology
  • Cancer Vaccines / immunology*
  • Carcinoembryonic Antigen / genetics*
  • Carcinoembryonic Antigen / immunology*
  • Enterotoxins / genetics*
  • Enterotoxins / immunology
  • Escherichia coli Proteins / genetics*
  • Escherichia coli Proteins / immunology
  • Female
  • Genetic Vectors
  • Immunization
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Neoplasms, Experimental / therapy*
  • Recombinant Fusion Proteins / immunology*
  • T-Lymphocytes, Regulatory / physiology
  • Vaccines, Synthetic / immunology*


  • Adjuvants, Immunologic
  • Bacterial Toxins
  • Cancer Vaccines
  • Carcinoembryonic Antigen
  • Enterotoxins
  • Escherichia coli Proteins
  • Recombinant Fusion Proteins
  • Vaccines, Synthetic
  • heat-labile enterotoxin, E coli