FIG. 4.

Recycling of MHC-I molecules in MCMV-infected cells. (A) Recycling efficiencies, expressed as the percentage recycled, and recycling kinetics, expressed as the t_1/2 required to reach the maximal signal, were determined for uninfected and Δm138-MCMV-infected (6 h p.i.) fibroblasts after 1 h of internalization of K^d-MAb complexes. Recycled complexes were captured by Alexa⁴⁸⁸-conjugated anti-mouse IgG2b, and fluorescence intensity was determined by flow cytometry. (B) Recycling of internalized Tf determined by Western blot detection of intracellular Tf-biotin. The loss of Tf-biotin from cells occurs by recycling. Quantification was made by densitometry of blots, and results are expressed as a percentage of Tf-biotin after internalization (control value). Shown are data from one representative experiment out of four experiments. (C) Recycling of internalized (i) D^d-MAb (red fluorescence) from the juxtanuclear retention compartment at 16°C. Recycled (r) D^d-MAb was captured by Alexa⁴⁸⁸-conjugated anti-mouse IgG2a (green fluorescence) and stacked in subplasmalemmal endosomes at 16°C. Bars, 10 μm.