Dendritic cells use the C-type lectin CD206 (Mannose Receptor) to recognize fungal cells. Neumann and Jacobson (doi:10.1371/journal.ppat.1000760) report the discovery of the fungipod, a novel protrusive structure triggered on dendritic cells after CD206 engagement by yeast. Fungipods are long, conical motile structures with abundant F-actin, as shown in this projection image of a phalloidin-stained dendritic cell bearing several fungipods. Both S. cerevisiae and some pathogenic Candida species induce fungipods.

Image Credit: Aaron K. Neumann and Ken Jacobson, University of North Carolina, Chapel Hill

2010-02-26T08:00:00Z

Quantitative Comparison of HTLV-1 and HIV-1 Cell-to-Cell Infection with New Replication Dependent Vectors

2010-02-26T08:00:00Z

Author Summary

Cell-free virus particles released from infected cells can be transmitted to target cells by diffusion or may be conveyed directly to target cells via specific intercellular contacts; the latter is referred to as cell-to-cell infection. Microscopic imaging has shown how viral proteins and virus particles move within and between cells, accumulating at sites of cell-cell contact. While we suspect that these images represent virus infection, it has been difficult to accurately quantify virus replication and provirus formation in most cell-to-cell infection experiments. Retroviral vectors that encode reporter proteins have been invaluable tools for analyzing retrovirus replication and restriction, but they have had limited utility in cell-to-cell infection studies due to high background noise resulting from reporter expression in the producer cells. We report the construction and characterization of retroviral vectors that express reporter protein exclusively in target cells and only after completing a full replication cycle. We have validated this approach and have begun to analyze cell and virus determinants for cell-to-cell infection with vectors for two human retroviruses that infect T cells. We show that the mechanism of transmission and ensuing virus replication depend on the particular virus, the effector and target cell types, and on the specific type of cell-cell interaction.

Differentiation, Distribution and γδ T Cell-Driven Regulation of IL-22-Producing T Cells in Tuberculosis

2010-02-26T08:00:00Z

Author Summary

2010-02-19T08:00:00Z

Author Summary

In man, hantavirus cardiopulmonary syndrome (HCPS) caused by Andes Virus (ANDV) is endemic in the Southern cone of Chile and Argentina but cases of HCPS are being increasingly reported all over South America since 1995. HCPS is characterized by fulminant pulmonary edema which progresses to shock and death in about 36% of patients with HCPS. Nevertheless, to date, neither antiviral treatments nor vaccines inducing neutralizing antibodies (NAb) have proven effective against HCPS-causing hantaviruses. We set out for the first study on human cellular immunity towards ANDV in 78 convalescent survivors of ANDV infection. We found that Gn-specific responses were predominant as compared to N- and Gc-specific responses, even up to 13 years after the infection. Surprisingly, most of the Gn-specific responses were restricted to two neighboring epitopes within the Gn carboxyterminus. Interestingly, among HLA-B*3501⁺ patients, Gn_465−473-specific CD8⁺ T-cells showed highly differentiated but resting phenotype and functions. It remains to be seen in future studies whether the immunodominace of Gn-specific T-cells is crucial for protective immunity. Most intriguingly, titers of neutralizing antibodies increased in 10/17 individuals months to years after the acute infection and independently of whether they were residents of endemic areas or not. Thus, our data suggest viral persistence or latency in part of ANDV-convalescent patients. However, it remains a major task for future studies to proof the concept of latent/persistent human ANDV infection by the determination of viral antigen in convalescent patients.