Comparison of the cytokine immune response to pathogenic Yersinia enterocolitica bioserotype 1B/O:8 and 2/O:9 in susceptible BALB/C and resistant C57BL/6 mice

We investigated the lethality of pathogenic Yersinia enterocolitica bioserotypes 1B/O:8 and 2/O:9 in susceptible BALB/C and resistant C57BL/6 mice; the cytokine alterations and histopathological changes were observed comparing the two strains in BALB/C mice. The data showed the 50% lethal dose (LD50) for the pathogenic Y. enterocolitica bioserotype 1B/O:8 was 10(3) cfu in both BALB/C and C57BL/6 mice; while the LD50 for the 2/O:9 was 10(8) cfu in BALB/C mice and 10(9) cfu in C57BL/6 mice, a large difference. After infection with the two strains in BALB/C mice, GM-CSF (granulocyte-macrophage colony stimulating factor), IFN-gamma (interferon-gamma), (interleukin-1 beta), IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, and TNF-alpha (tumor necrosis factor-alpha) appeared as a cytokine storm in a short period, reached peak values, and then quickly decreased. This appeared important for the immune response and cytokine immunopathogenesis in pathogenic Y. enterocolitica infections. In the initial infection stage, GM-CSF, IL-6, and TNF-alpha of 2/O:9 were higher than 1B/O:8; and subsequently the status was reversed. However, levels of IFN-gamma, IL-1 p, IL-2, IL-4, 1L-5, IL-10, IL-12 following infection with 1B/O:8 were always higher than with 2/O:9. The histopathological changes in the liver and spleen in BALB/C mice infected with the two strains were similar at different times and doses. These observations show the different immunological effects and changes for pathogenic Y. enterocolitica 1B/O:8 and 2/O:9 infections using the mouse model. (C) 2013 Elsevier Ltd. All rights reserved.