Myeloid-derived suppressor cells help protective immunity to Leishmania major infection despite suppressed T cell responses.

Th1/Th2 cytokines play a key role in immune responses to Leishmania major by controlling macrophage activation for NO production and parasite killing. MDSCs, including myeloid precursors and immature monocytes, produce NO and suppress T cell responses in tumor immunity. We hypothesized that NO-producing MDSCs could help immunity to L.

Targeting caspases in intracellular protozoan infections.

Caspases are cysteine aspartases acting either as initiators (caspases 8, 9, and 10) or executioners (caspases 3, 6, and 7) to induce programmed cell death by apoptosis. Parasite infections by certain intracellular protozoans increase host cell life span by targeting caspase activation. Conversely, caspase activation, followed by apoptosis of lymphocytes and other cells, prevents effective immune responses to chronic parasite infection.

Inhibition of caspase-8 activity reduces IFN-gamma expression by T cells from Leishmania major infection.

Following infection with Leishmania major, T cell activation and apoptosis can be detected in draining lymph nodes of C57BL/6-infected mice. We investigated the mechanisms involved in apoptosis and cytokine expression following T cell activation. After two weeks of infection, apoptotic T cells were not detected in draining lymph nodes but activation with anti-CD3 induced apoptosis in both CD4 and CD8 T cells.

Histological approaches for high-quality imaging of zooplanktonic organisms.

The investigation of the internal organization of zooplankton communities provides important information on the plankton biology with special interest for the study of ecological processes. Zooplanktoners can play a structural function as indicators for ecosystem health or stress, but their study using histological techniques is still limited. Here we report that the internal structure of zooplanktonic organisms can be facilely observed by a histological approach that combines optimal fixation and processing with a plastic resin (glycol methacrylate) embedding, resulting in increased tissue resolution.

The Fas death pathway controls coordinated expansions of type 1 CD8 and type 2 CD4 T cells in Trypanosoma cruzi infection.

We investigated the role of the Fas ligand (FasL)/Fas death pathway on apoptosis and cytokine production by T cells in Trypanosoma cruzi infection. Anti-FasL, but not anti-TNF-alpha or anti-TRAIL, blocked activation-induced cell death of CD8 T cells and increased secretion of IL-10 and IL-4 by CD4 T cells from T. cruzi-infected mice.