Leishmania, innate immunity, and vaccine development
David M. Mosser, Ph.D.
Department of Cell Biology and Molecular Genetics
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Figure 1. Amastigotes growing inside a macrophage monolayer that was activated with IFN-γ. Two hours prior to IFN-γ treatment monolayers were treated with recombinant IL-10. These IL-10 pretreated macrophages are as permissive as resident macrophages for Leishmania growth. In this picture, monolayers were permeablized and stained with antisera to Leishmania amastigotes followed by FITC-conjugated anti-IgG. Amastigotes appear green. Macrophages were counterstained with Propridium iodide. Nuclei appear red. For details, see Mentink Kane, M. and Mosser, D.M. 2001. The role of IL-10 in promoting disease progression in Leishmaniasis. J. Immunology 166:1141-47. |
Figure 2.
The nuclear translocation of NF-κB was examined using fluorescence microscopy.
Monolayers of bone marrow-derived macrophages were infected with either Leishmania
amazonensis (left) or Rhodococcus equi (right). One hour later cells
were washed, permeablized and stained with an antibody to p65 followed by FITC-conjugated
anti-IgG. Following R. Equi infection there is a rapid nuclear translocation
of NF-κB into the nucleus (green). In macrophages infected with Leishmania,
however, the nuclei remain unstained. The p65 is diffuse throughout the cytoplasm
despite heavy parasite infection.
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Figure 3. Fluorescence confocal photomicrograph showing the localization of polymerized actin (green) around the “phagocytic cups” formed during the phagocytosis of Leishmania amazonensis amastigotes by macrophages. This specimen was counterstained with Propridium Iodide. The large red spheres represent macrophage nuclei. The small red dots represent parasite nuclei and kinetoplast. Some of the parasites can be clearly seen within structures that are partially or completely surrounded by f-actin. For details, see Love, D.C., Kane, M.M. and Mosser, D.M. 1998. Leishmania amazonensis: the phagocytosis of amastigotes by macrophages. Exp. Parasitol. 88:161-171. |