Figure 3

Infection with Francisella increases expression of transferrin receptor. A. RAW264.7 macrophages were infected with Francisella that constitutively expressed Gfp. After 2 h infected cells were fixed and processed for immunofluorescence with a mouse anti-TfR1 antibody followed by an Alexa594 conjugated goat-anti-mouse IgG (red fluorescence). Single confocal planes for merged fluorescence channels are shown. B. RAW264.7 cells were infected with live or formalin-inactivated Francisella (dead) for two and twenty-four hours. Immunoblotting of solubilized proteins was done with mouse anti-TfR1 and mouse anti-GAPDH as control. Visualization was by chemiluminescence. C. mRNA levels for TfR1 in RAW264.7 macrophages were determined after 2 or 24 h of infection with Francisella by quantitative light cycler PCR; levels are normalized to GAPDH-mRNA levels. Means of n = 6 experiments +/- 1 standard error of mean (SEM) are shown.