Stimulation with type I IFN results in reduced B-cell homing to Peyer’s patches. Purified splenic B cells were cultured in the presence of recombinant IFN-α for 24 hours. (A) Surface expression of CD69, CD62L, and α4β7 was determined by flow cytometry. (B) Splenic B cells were either stimulated with IFN-α or treated with adhesion molecule–blocking antibodies. Binding of the fluorescently labeled cells to plate-bound MAdCAM-1 was determined by spectrophotometer. All data give the mean value of triplicate samples ± SEM. (C) IFN-α–stimulated splenic B cells were fluorescently labeled and adoptively transferred into naïve recipient mice. Four hours later, recipients were euthanized, and lymphoid organs assessed for the presence of transferred B cells. The HI represents the ratio of IFN-α–activated B cells to unstimulated B cells. Data show the mean value of individual recipient mice (n = 3) ± SEM. The asterisk indicates comparison with the HI for the spleen. (D) Mice were injected intraperitoneally with an anti-α4β7 or an isotype control antibody. Twenty-four hours later, cell numbers in secondary lymphoid organs were determined by flow cytometry. Data show the mean value of individual mice (n = 7 for Peyer’s patches and spleen, n = 4 for PLNs) ± SEM pooled from 2 independent experiments. All data are representative of at least 2 independent experiments. LFA-, lymphocyte function-associated antigen 1; MFI, mean fluorescence intensity; PP, Peyer's patches; Unstim, unstimulated.
