oral Salmonella vaccine promotes the down-regulation of cell surface Toll-like receptor 4 (TLR4) and TLR2 expression in mice

• Published in: FEMS immunology and medical microbiology 2007-08, Vol.50 (3), p.300-308
• Main Authors: Eguchi, Masahiro, Sekiya, Yukie, Suzuki, Masato, Yamamoto, Tomoko, Matsui, Hidenori
• Format: Article
• Language: English
• Subjects: Administration, Oral; Animals; Applied microbiology; Bacteriology; Biological and medical sciences; CD4-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - immunology; Cell surface; Cross-protection; Down-regulation; Female; Fundamental and applied biological sciences. Psychology; Immune system; Immune Tolerance; Immunization; Immunological tolerance; immunosuppression (physiological); Listeria; Listeria challenge; Listeria monocytogenes; Listeriosis - prevention & control; live Salmonella vaccine; macrophage; Macrophages; Macrophages, Peritoneal - immunology; Mice; Mice, Inbred BALB C; Microbiology; Miscellaneous; Peritoneum; Proteins; Salmonella; Salmonella enterica; Salmonella Infections - prevention & control; Salmonella typhimurium; Salmonella Vaccines - administration & dosage; Salmonella Vaccines - immunology; TLR2 protein; TLR4 protein; Toll-like receptor; Toll-Like Receptor 2 - antagonists & inhibitors; Toll-Like Receptor 2 - metabolism; Toll-Like Receptor 4 - antagonists & inhibitors; Toll-Like Receptor 4 - metabolism; Toll-like receptors; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects)
• ISSN: 0928-8244; 1574-695X; 2049-632X
• DOI: 10.1111/j.1574-695X.2007.00240.x

A single oral immunization with the Lon-protease-deficient Salmonella enterica serovar Typhimurium (strain CS2022) induced protective immunity in mice against a subcutaneous challenge with virulent Listeria monocytogenes as well as virulent Salmonella serovar Typhimurium. The populations of cell surface Toll-like receptor 4 (TLR4) and TLR2 on peritoneal macrophages decreased at week 6 after immunization. This population decrease was not reversed after a challenge with either Salmonella or Listeria. These results suggest that oral immunization with CS2022 induced immune tolerance correlated with the down-regulation of cell surface TLR expression. This down-regulation may in part account for the development of cross-protection against a Listeria challenge by immunization with CS2022.