HIV-1 indirectly affects the uptake of Leishmania parasites inside monocyte-derived macrophages.

“Concurrent uncontrolled development of human immunodeficiency virus type 1 (HIV-1) and Leishmania spp. is regarded as an emerging pathogenic combination in countries where human beings are exposed to these two micro-organisms.

“The present study was aimed at exploring whether HIV-1 development within a culture of human monocyte-derived macrophages (MDMs) affected the further development of luciferase-encoding Leishmania infantum using the luciferase activity as a readout assay,” scientists in Canada report.

According to C.Q. Zhao and colleagues at Laval University in Quebec City, “It was demonstrated that, in cultures of HIV-1-loaded MDMs; exposed to axenic amastigotes, the luciferase activity was higher than in HIV-1-free MDMs.

“As a preliminary approach to deciphering the possible mechanism through which HIV-1 can affect Leishmania infantum, attention was focused on the very early processes that could underlie this increased luciferase activity.”

“Using GFP-labeled parasites, it was possible to establish that, in HIV-1-infected MDMs, the percentage of GFP-expressing MDMs was higher (10-20%) than in cell cultures not exposed to HIV-1 (5%).

“Two-color immunofluorescence staining suggested that HIV-1 indirectly affects the uptake of parasites inside MDMs. Thus, the observed phenomenon seems to be linked with a higher uptake of parasites within MDMs,” researchers wrote.

“Taken together,” concluded Zhao, “the data reported here may contribute to our understanding of disseminated Leishmania infection in HIV-1-infected individuals.”

Zhao and colleagues published their study in the Journal of General Virology (In primary human monocyte-derived macrophages exposed to Human immunodeficiency virus type 1, does the increased intracellular growth of Leishmania infantum rely on its enhanced uptake? J Gen Virol, 2006;87(Part 5):1295-1302).

For more information, contact M.J. Tremblay, CHUL, Research Center, Research Center Infectious Disease, RC709, 2705 Laurier Blvd., Quebec City, PQ G1V 4G2, Canada.

Publisher contact information for the Journal of General Virology is: Society General Microbiology, Marlborough House, Basingstoke Rd., Spencers Woods, Reading RG7 1AG, Berks, England.