engleski

Indoleamine 2, 3-dioxygenase mRNA expression in different tissues of neonatal mice during Listeria monocytogenes infection

L. monocytogenes infection causes serious morbidity during the fetal and neonatal period. Bacterium has a predilection for placenta and brain tissue. Previous studies have shown the involvement of the indoleamine 2, 3-dioxygenase (IDO) in maintaining the immune privilege of these organs. In this study we investigate the role of TNF receptor 1 (TNFR1) in IDO regulation during experimental neonatal listeriosis. We infected wild-type (WT) C57BL/6 and TNFR1 knockout (KO) newborn mice with attenuated actA-deficient L. monocytogenes. Tissue levels of IDO mRNA were detected by RT-PCR. The extent of cell infiltration in the organs was assessed using immunohistochemical methods. The number of bacteria in tissue was determined using conventional microbiological techniques. Infection resulted in a hyperinflammatory and ultimately fatal host reaction and high bacterial load in KO mice in contrast to 100% survival rate without clinical disease in WT mice. The basal levels of IDO in WT and KO mice were the highest in the brain tissue. After infection basal levels of IDO mRNA transcription in liver, spleen and brain of WT mice were retained while in KO mice were enhanced. Macrophage tissue infiltration was paralleled by an induction of IDO mRNA in KO L. monocytogenes infected mice. KO mice succumbed to uncontrolled infection and inflammation mediated injury, despite high local IDO mRNA expression. TNFR1 is required for the efficient antilisterial host immune response.

Listeria monocytogens ; neonatal mice ; IDO ; TNFR1KO

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