Yersinia

Studies from State University of New York in the area of immunology published

"An autophagic process known as xenophagy, which destroys pathogens in acidic autophagolysosomes, can occur in naive macrophages and is upregulated in activated macrophages. Studies were undertaken here to investigate the mechanism of Y. pestis survival in phagosomes of naive and activated macrophages and to determine if the pathogen avoids or co-opts autophagy. Colocalization of the YCV with markers of autophagosomes or acidic lysosomes and the pH of the YCV were determined by microscopic imaging of infected macrophages. Some YCVs contained double membranes characteristic of autophagosomes, as determined by electron microscopy. Fluorescence microscopy showed that similar to 40% of YCVs colocalized with green fluorescent protein (GFP)-LC3, a marker of autophagic membranes, and that YCVs failed to acidify below pH 7 in naive macrophages. Replication of Y. pestis in naive macrophages caused accumulation of LC3-II, as determined by immunoblotting. While activation of infected macrophages increased LC3-II accumulation, it decreased the percentage of GFP-LC3-positive YCVs (similar to 30%). A viable count assay showed that Y. pestis survived equally well in macrophages proficient for autophagy and macrophages rendered deficient for this process by Cre-mediated deletion of ATG5, revealing that this pathogen does not require autophagy for intracellular replication," wrote C. Pujol and colleagues, State University of New York.

The researchers concluded: "Although YCVs can acquire an autophagic membrane and accumulate LC3-II, the pathogen avoids xenophagy by preventing vacuole acidification.."

Pujol and colleagues published their study in Infection and Immunity (Yersinia pestis Can Reside in Autophagosomes and Avoid Xenophagy in Murine Macrophages by Preventing Vacuole Acidification. Infection and Immunity, 2009;77(6):2251-2261).

For additional information, contact J.B. Bliska, SUNY Stony Brook, Center Infectious Disease, Stony Brook, NY 11794, USA.

Publisher contact information for the journal Infection and Immunity is: American Society Microbiology, 1752 N St. NW, Washington, DC 20036-2904, USA.

Keywords: United States, Stony Brook, Life Sciences, Bacteriology, Bubonic Plague, Yersinia Pestis, Interferon, Immunology, State University of New York.

This article was prepared by Medical Imaging Law Weekly editors from staff and other reports. Copyright 2009, Medical Imaging Law Weekly via NewsRx.com.