Salmonella vaccine carrier strains: Effective delivery system to trigger anti-tumor immunity by oral route

Eva Medina, Carlos A. Guzmán, Lothar H. Staendner, Mario P. Colombo, Paola Paglia

Research output: Contribution to journalArticlepeer-review


Recombinant Salmonella strains expressing heterologous antigens can be delivered by oral route triggering the elicitation of efficient antigen-specific humoral, T helper and cytotoxic responses. The potential of attenuated Salmonella spp. to trigger anti-tumor immunity was evaluated for the first time by using β-galactosidase (β-gal) as a model tumor-associated antigen (TAA). β-gal was expressed in a Salmonella typhimurium aroA vaccine carrier strain either constitutively or under the control of a promoter activated upon infection. Oral immunization with both vaccine prototypes resulted in the elicitation of β-gal specific humoral and cell-mediated immunity. Although both strains were able to trigger antigen-specific CTL, responses were more efficient when the expression was controlled by the promoter activated upon infection. The anti-tumor efficacy of the stimulated response was validated by challenging vaccinated animals with an aggressive fibrosarcoma transfected with β-gal, which operationally acts as a TAA. Both groups of vaccinated mice exhibited a significant reduction in tumor take and growth with respect to animals vaccinated with plasmidless carrier (p <0.05). However, the overall efficiency was better in the group in which β-gal was controlled by the in vivo-activated promoter (85% versus 54%; p <0.05).

Original languageEnglish
Pages (from-to)693-699
Number of pages7
JournalEuropean Journal of Immunology
Issue number2
Publication statusPublished - 1999


  • Anti-tumor immunity
  • Live carrier
  • Oral vaccine
  • Salmonella typhimurium

ASJC Scopus subject areas

  • Immunology


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