Several reports have brought to light new and interesting findings on the involvement of autophagy and apoptosis in pathogenesis of viral and bacterial diseases, as well as presentation of foreign antigens. Our model studies focused on the involvement of apoptosis during replication of highly virulent Moscow strain of ectromelia virus (ECTV-MOS). Here, we show evidence that autophagy is induced during mousepox replication in a cell line. Fluorescence microscopy revealed increase of LC3 (microtubule-associated protein 1 light chain 3) aggregation in infected as opposed to non-infected control L929 cells. Furthermore, Western blot analysis showed that replication of ECTV-MOS in L929 cells led to the increase in LC3-II (marker of autophagic activity) expression. Beclin 1 strongly colocalized with extranuclear viral replication centers in infected cells, whereas expression of Bcl-2 decreased in those centers as shown by fluorescence microscopy. Loss of Beclin 1-Bcl-2 interaction may lead to autophagy in virus-infected L929 cells. To assess if Beclin 1 has a role in regulation of apoptosis during ECTV-MOS infection, we used small interfering RNA directed against beclin 1 following infection. Early and late apoptotic cells were analyzed by flow cytometry after AnnexinV and propidium iodide staining. Silencing of beclin 1 resulted in decreased percentage of early and late apoptotic cells in the late stage of ECTV-MOS infection in L929 cells. We conclude that Beclin 1 plays an important role in regulation of both, autophagy and apoptosis, during ECTV-MOS replication in L929 permissive cells.
Aims: The objective of this study was to access APC–effector cell cluster formation in genetically susceptible BALB/c (H‐2d) mice infected with highly virulent Moscow strain of ectromelia virus (ECTV‐MOS) and estimate of lymphocyte activation based upon expression of CD62L and CD44 molecules.
Methods and Results: APC–effector cell clusters were obtained by enzymatic digestion from draining lymph nodes (DLNs) and spleens of BALB/c mice. We found that APCs infected with ECTV‐MOS form unstable clusters with effector cells, and thus may diminish T‐cell activation at the early stage of mousepox. Different types of effector cells including T‐cell subsets (CD4+ and CD8+), B cells and polymorphonuclear cells colocalize within individual clusters. Increase in CD19+ B cells within APC–effector cell clusters during severe clinical mousepox may reflect B‐cell activation.
Conclusions: Our studies indicated vigorous changes in APC–effector cell cluster formation in genetically susceptible BALB/c mice during mousepox (up to 2 weeks). ECTV‐MOS can modulate APC interactions with effector cells and consequently may impair T‐cell activation probably owing to unstable cluster formation and/or subsequent weak stimulation by infected APCs at the early stages of mousepox.
Significance and Impact of the Study: This is the first report of APC–effector cell cluster formation in BALB/c mice during mousepox. It gives us a new light on the mutual cell–cell interactions and development of the immune response during ECTV‐MOS infection.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.