Replication And Distribution Of Toxoplasma Gondii In The Small Intestine After Oral Infection With Tissue Cysts

Infect Immun. 2013 Mar 4. [Epub ahead of print]

Replication And Distribution Of Toxoplasma Gondii In The Small Intestine After Oral Infection With Tissue Cysts

Gregg B, Taylor BC, John B, Tait-Wojno ED, Girgis NM, Miller N, Wagage S, Roos DS, Hunter CA.

Departments of Biology Penn Genome Frontiers Institute.

Natural infection by Toxoplasma gondii occurs via oral ingestion of tissue cysts that rupture in the small intestine releasing zoites that infect locally before disseminating throughout the host. The studies presented here use fluorescent parasites combined with flow cytometry and multi-photon microscopy techniques to understand the events associated with parasite replication in the mucosa. At three days post-infection with tissue cysts, parasites were localized in small foci and flow cytometry revealed parasites present in macrophages, neutrophils, and monocytes in the lamina propria. By day six post-infection there were large foci of replicating parasites; however, foci unexpectedly varied in the number of villi involved and were associated with the presence of viable tachyzoites within the intestinal lumen. Consistent with the flow cytometry data, neutrophils and monocytes in the lamina propria were preferentially associated with parasite plaques. In contrast, dendritic cells comprised a small fraction of the infected immune cell population and were localized at the periphery of parasite plaques. Together, these findings reveal the formation of localized sites of parasite replication and inflammation early during infection and suggest that sustained replication of T. gondii in the gut may be a function of pathogen luminal spread.

PMID: 23460516 [PubMed - as supplied by publisher]