MKs can process OVA into peptides. MKs were pulsed with DQ-OVA and fluorescence was monitored over 60 minutes at 37°C (A). Scale bars represent 10 µm, except in 2 right panels scale bars represent 2 μm. MKs were incubated with 0, 100, or 500 µg/mL of DQ-OVA for 1, 4, or 24 hours at 37°C or on ice (B). Two-way ANOVA P < .01 and 1-way ANOVA with a Tukey correction for multiple testing at 24 hours; n = 4; mean with standard deviation (SD). Incubation of MKs with the proteasome inhibitor, MG132, or with the tubulin dynamic inhibitor, Nocodazole, was used to assess the proteasome and cytoskeleton contribution, respectively, to OVA processing (C). One-way ANOVA with a Tukey correction for multiple testing; n = 5; mean with SD; ****P < .0001; **P < .01; each n corresponds to an independent MK donor mouse.