Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

This Article Full Text (PDF, 1144K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JEM Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Van Epps, H. L. Search for Related Content PubMed Articles by Van Epps, H. L. Related Collections Related Article Social Bookmarking                            What's this?

A disease-causing bacterium uses a tick (shown) salivary protein to establish infection in the insect's salivary glands. Pal/MacmillanIN THIS ISSUE

The bacterium Anaplasma phagocytophilum uses a tick protein to help it set up camp in the insect's salivary glands, according to Sukumaran and colleagues (page 1507).

Many tick-borne pathogens hijack host proteins to establish infection in their tick vector or mammalian host. Previous work by this group, for example, showed that the Lyme disease bacterium Borrelia burgdorferi induces the expression of the salivary protein Salp15 in infected Ixodes scapularis ticks as they feed. The bacterium then coats itself with Salp15 as it exits the tick, creating a shield against the destructive antibodies encountered in the mammalian host.

Here, Sukumaran and colleagues used a similar approach to study the obligate intracellular bacterium A. phagocytophilum, which causes a common and sometimes deadly tick-borne disease in humans called anaplasmosis (formerly granulocytic ehrlichiosis). They found that if I. scapularis ticks fed on A. phagocytophilum–infected mice, the ticks selectively increased their expression of the salivary protein Salp16.

But in this case, Salp16 was used for protection in the tick, not the mammalian host. Inhibiting Salp16 expression in the tick (using RNAi) reduced the number of bacteria in the insect's salivary glands, suggesting that Salp16 was needed for the bacterium to establish a foothold in the salivary gland where it resides after migrating from the gut. Once there, however, the bug no longer required Salp16 to maintain its residence. Inhibiting Salp16 had no effect on transmission of the bug to the mouse reservoir or on the initial uptake of the bug (with the blood meal) into the tick gut.

The authors are now trying to determine how Salp16 helps A. phagocytophilum to colonize the salivary gland. In the meantime, blocking Salp16 in ticks might provide a way to disrupt the transmission cycle of the pathogen and thus lower the prevalence of disease.

hvanepps{at}rockefeller.edu

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

Related Article

An Ixodes scapularis protein required for survival of Anaplasma phagocytophilum in tick salivary glands

Bindu Sukumaran, Sukanya Narasimhan, John F. Anderson, Kathleen DePonte, Nancy Marcantonio, Manoj N. Krishnan, Durland Fish, Sam R. Telford, Fred S. Kantor, and Erol Fikrig
J. Exp. Med. 2006 203: 1507-1517. [Abstract] [Full Text] [PDF]

This Article Full Text (PDF, 1144K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JEM Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Van Epps, H. L. Search for Related Content PubMed Articles by Van Epps, H. L. Related Collections Related Article Social Bookmarking                            What's this?