Journal: Infection and Immunity
Article Title: Rickettsia heilongjiangensis suppresses RIPK1 kinase-mediated host cell death during the infection
doi: 10.1128/iai.00158-25
Figure Lengend Snippet: Rh -B8 infection-induced host cell apoptosis in vivo and in vitro . (a) Survival analysis of Ifnar -/- mice infected with Rh -B8 ( n = 9) compared to control mice injected with SPG buffer ( n = 6). All mice died within one week following intravenous injection of Rh -B8. (b) Spleen tissue from Rh -B8-infected Ifnar -/- mice exhibited enlargement and more severe pathological changes compared to uninfected mice. TUNEL staining on splenic paraffin sections revealed a multitude of apoptotic cells (red). Scale bar, 20 µm. Nuclei were indicated by blue DAPI staining. (c) Bacterial counts in tissues, including the spleen, liver, kidney, lung, and brain from five Rh -B8-infected Ifnar -/- mice, were quantified using plaque assay. Means are shown with error bars representing ±SEM. (d) During infection at a multiplicity of infection (MOI) of 1.0, Rh -B8 exhibited slow propagation in the early stages of infection, followed by exponential growth starting at 48 hours post-infection (hpi). In parallel, the viability of HMEC-1 cells decreased significantly by 72 hpi. Data are expressed as mean ± standard deviation (SD), with each experiment conducted in biological triplicates, and results were averaged across all replicates. (e) Immunofluorescence microscopy images demonstrated an increase in the number of apoptotic HMEC-1 cells during Rh -B8 infection. Apoptotic cells were labeled using TUNEL staining (green), nuclei were visualized with DAPI (blue), and bacteria were detected using an anti-OmpB antibody (red). Scale bars, 20 µm.
Article Snippet: Finally, the cell side of the coverslip was inverted onto a microscope slide containing a DAPI anti-fade reagent (Beyotime, P0131).
Techniques: Infection, In Vivo, In Vitro, Control, Injection, TUNEL Assay, Staining, Plaque Assay, Standard Deviation, Immunofluorescence, Microscopy, Labeling, Bacteria