Factors affecting immune responses to Salmonella vaccine reported.

2004 JUL 7 - (NewsRx.com & NewsRx.net) -- Scientists outline the host and bacterial factors affecting induction of immune responses to flagellin expressed by attenuated Salmonella vaccine strains in a recent issue of Infection and Immunity.

"Previous observations demonstrated that the delivery of recombinant Salmonella enterica serovar Dublin strains to mice via mucosal routes did not efficiently activate systemic and secreted antibody responses to either type d flagellin or genetically fused heterologous B-cell epitopes, thus reducing the usefulness of the protein as a carrier of epitopes for vaccine purposes. In this work, we investigated murine systemic and mucosal flagellin immunogenicity after oral immunization with attenuated Salmonella strains," scientists in Brazil report.

"The reduced anti-type d flagellin antibody responses in mice immunized via mucosal routes with three doses of flagellated S. enterica serovar Dublin strains were not caused by oral tolerance and could not be restored by co-administration of a mucosal adjuvant," said Maria Elisabete Sbrogio-Almeida and colleagues at Sao Paulo University. "The induction of antibody responses to Salmonella flagellins was shown to differ according to the genetic background, but not the haplotype, of the mouse lineage."

"Moreover, BALB/c mice orally immunized with S. enterica serovar Typhimurium strains developed anti-type i flagellin sera and secreted antibody responses, which indicated that the serovar of the Salmonella vaccine strain also affected flagellin immunogenicity," stated Sbrogio-Almeida and her collaborators. "Analyses of cytokine responses of BALB/c mice immunized with three oral doses of flagellated S. enterica serovar Dublin vaccine strains showed that, in spite of the lack of antibody responses, elevated type d flagellin-specific CD4-cell-activation-dependent gamma interferon (IFN-gamma) and ...