Fig. 4: MHCII is enriched underneath H18N11 viral particle upon attachment. | Nature Communications

Fig. 4: MHCII is enriched underneath H18N11 viral particle upon attachment.

From: The bat influenza A virus subtype H18N11 induces nanoscale MHCII clustering upon host cell attachment

Fig. 4: MHCII is enriched underneath H18N11 viral particle upon attachment.

a Viral particle tracking on the cell surface. Fluorescently-labeled viral particles were added to cells expressing MHCIITagRFP (wt) or MHCIITagRFPmut (mut). Scale bar 10 µm b Representative trajectories of viral particles on cells expressing MHCIITagRFP or MHCIITagRFPmut (right) and comparison of the cumulative track length from one experiment (left). wt: n = 97, mut: n = 79 c Inverse attachment assay. Labeled viral particles were immobilized and cells stably expressing MHCIImEos were seeded on top. Tracking of MHCIImEos molecules on top of H18N11 (d) or H1N1 (e) particles (white). Representative figures from n = 2 experiments. Scale bars: 1 µm (overviews) and 500 nm (zoom-ins). f Power-law exponent α of MHCII molecules on the surface of cells exposed to the indicated viruses at virus-bound areas (n = 2 experiments). Mock-infected cells served as control. wt+H18N11: n = 1027, wt+H1N1: n = 1042, mut+H18N11: n = 1017, wt + mock: n = 1021, mut + mock: n = 1025. g To calculate if a slowdown of receptor proteins at the virus binding site leads to local protein enrichment, we simulated the 2D random diffusion of MHCII using our measured diffusion coefficient DMHCII = 0.032 µm2/s. We added circular regions (red, r = 50 nm) to the simulation, where proteins were slowed down according to our PALM measurements to DMHCII+H18 = 0.015 µm2/s. We simulated 4000 time steps with 30 ms interval. We examined the number of receptors associated with circular regions (i.e., viruses). Each data point represents one simulation (n = 30). b, f, g Unpaired two-tailed Student’s t-test was used for pairwise comparison. b ****p < 0.0001 f ****p < 0.0001 for wt + H18N11 vs. wt + H1N1, ***p = 0.0002 for wt + H18N11 vs. mut + H18N11, ****p < 0.0001 for wt + H18N11 vs. wt w/o, ****p < 0.0001 for wt + H18N11 vs. wt w/o, ns: not significant. g ****p < 0.0001. a, c Schemes were created with BioRender.com (https://BioRender.com/c35p533). b, f, g Source data are provided as a Source Data file.

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