Comparison of Two Mice Strains, A/J and C57BL/6, in Caspase-1 Activity and IL-1β Secretion of Macrophage to Mycobacterium leprae Infection

A/J mice were found to have amino acid differences in Naip5, one of the NOD-like receptors (NLRs) involved in the cytosolic recognition of pathogen-associated molecular patterns and one of the adaptor proteins for caspase-1 activation. This defect was associated with a susceptibility to Legionella infection, suggesting an important role for Naip5 in the immune response also to other intracellular pathogens, such as Mycobacterium leprae. In this study, the immune responses of macrophages from A/J mice against M. leprae were compared to those of macrophages from C57BL/6 mice. Infection with M. leprae induced high levels of TNF-α production and NF-κB activation in A/J and C57BL/6 macrophages. Caspase-1 activation and IL-1β secretion were also induced in both macrophages. However, macrophages from A/J mice exhibited reduced caspase-1 activation and IL-1β secretion compared to C57BL/6 macrophages. These results suggest that NLR family proteins may have a role in the innate immune response to M. leprae

Tissue-specific down-regulation of RIPK 2 in Mycobacterium leprae-infected nu/nu mice.

RIPK 2 is adapter molecule in the signal pathway involved in Toll-like receptors. However, there has been no reported association between receptor-interacting serine/threonine kinase 2 (RIPK 2) expression and the infectious diseases involving mycobacterial infection. This study found that its expression was down-regulated in the footpads and skin but was up-regulated in the liver of Mycobacterium leprae-infected nu/nu mice compared with those of the M. leprae non-infected nu/nu mice. It was observed that the interlukin-12p40 and interferon-gamma genes involved in the susceptibility of M. leprae were down-regulated in the skin but were up-regulated in the liver. Overall, this suggests that regulation of RIPK 2 expression is tissue-specifically associated with M. leprae infection

Comparison of Two Mice Strains, A/J and C57BL/6, in Caspase-1 Activity and IL-1β Secretion of Macrophage to Mycobacterium leprae Infection

A/J mice were found to have amino acid differences in Naip5, one of the NOD-like receptors (NLRs) involved in the cytosolic recognition of pathogen-associated molecular patterns and one of the adaptor proteins for caspase-1 activation. This defect was associated with a susceptibility to Legionella infection, suggesting an important role for Naip5 in the immune response also to other intracellular pathogens, such as Mycobacterium leprae. In this study, the immune responses of macrophages from A/J mice against M. leprae were compared to those of macrophages from C57BL/6 mice. Infection with M. leprae induced high levels of TNF-α production and NF-κB activation in A/J and C57BL/6 macrophages. Caspase-1 activation and IL-1β secretion were also induced in both macrophages. However, macrophages from A/J mice exhibited reduced caspase-1 activation and IL-1β secretion compared to C57BL/6 macrophages. These results suggest that NLR family proteins may have a role in the innate immune response to M. leprae