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Roles of Salmonella enterica serovar Typhimurium encoded Peptidase N during systemic infection of Ifnγ(-/-) mice.

Bhosale,, Manoj and Kadthur, Jayachandra C and Nandi, Dipankar (2012) Roles of Salmonella enterica serovar Typhimurium encoded Peptidase N during systemic infection of Ifnγ(-/-) mice. In: Immunobiology, 217 (3). pp. 354-362.

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Abstract

Pathogen encoded peptidases are known to be important during infection; however, their roles in modulating host responses in immunocompromised individuals are not well studied. The roles of S. typhimurium (WT) encoded Peptidase N (PepN), a major aminopeptidase and sole M1 family member, was studied in mice lacking Interferon-γ (IFNγ), a cytokine important for immunity. S. typhimurium lacking pepN (ΔpepN) displays enhanced colony forming units (CFU) compared to WT in peripheral organs during systemic infection in C57BL/6 mice. However, Ifnγ(-/-) mice show higher CFU compared to C57BL/6 mice, resulting in lower fold differences between WT and ΔpepN. Concomitantly, reintroduction of pepN in ΔpepN (ΔpepN/pepN) reduces CFU, demonstrating pepN-dependence. Interestingly, expression of a catalytically inactive PepN (ΔpepN/E298A) also lowers CFU, demonstrating that the decrease in CFU is independent of the catalytic activity of PepN. In addition, three distinct differences are observed between infection of C57BL/6 and Ifnγ(-/-) mice: First, serum amounts of TNFα and IL1β post infection are significantly lower in Ifnγ(-/-) mice. Second, histological analysis of C57BL/6 mice reveals that damage in spleen and liver upon infection with WT or ΔpepN is greater compared to ΔpepN/pepN or ΔpepN/E298A. On the other hand, Ifnγ(-/-) mice are highly susceptible to organ damage by all strains of S. typhimurium used in this study. Finally, greater survival of C57BL/6, but not Ifnγ(-/-) mice, is observed upon infection with ΔpepN/pepN or ΔpepN/E298A. Overall, the roles of the host encoded IFNγ during infection with S. typhimurium strains with varying degrees of virulence are highlighted.

Item Type: Journal Article
Additional Information: Copyright to this article belongs to Elsevier
Keywords: Host response;Immunocompromised;IFN;Infection;Peptidase;S. typhimurium
Department/Centre: Division of Biological Sciences > Biochemistry
Date Deposited: 21 Feb 2012 08:03
Last Modified: 21 Feb 2012 08:03
URI: http://eprints.iisc.ernet.in/id/eprint/43580

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