Disruption of EAE pathogenesis by B cell depletion.
Panel A. EAE severity is similar in WTLM and hCD20Tg mice. EAE onset and severity were monitored using a 5-point scale on WTLM and hCD20Tg mice immunized with MOG1–125. These results are representative of at least two independent experiments. Panels B–D. Rituximab administration prevents the induction of EAE. WTLM or hCD20Tg mice were either left untreated or were injected with 100 µg Rituximab daily for three days (Day -3,-2,-1). On Day 0, EAE was induced by immunization with MOG1–125. Panel B. Disease course of WTLM and hCD20Tg mice, EAE onset and severity was monitored using a 5-point scale. Shown are the mean clinical score +/− SEM. Panel C. B cell depletion results in reduced levels of anti-MOG IgG in the serum. Serum was harvested on day 21 post-immunization and MOG-specific IgG levels were determined by ELISA. Results shown are the mean IgG concentration +/− SEM. Asterix indicates significant decrease as compared to Rituximab-treated WTLM mice. Panel D. Rituximab administration results in rapid depletion of B cells in the peripheral blood. Blood was taken from WTLM or hCD20Tg mice 3 days following the final dose of Rituximab (day 2 post-immunization). B cells were identified by flow cytometry using gates to identify lymphocytes and CD19 expressing cells. Results shown are the mean percentages of CD19+ B cells +/−SEM (*, p<0.01). Panels E/F. Treatment with Rituximab reduces EAE severity. EAE was initiated in WTLM and hCD20Tg mice on Day 0. Upon the appearance of clinical signs of EAE, Rituximab (100 µg) was administered daily for three treatments. Panel E. Disease course of WTLM and hCD20Tg mice, EAE onset and severity was monitored using a 5-point scale. Shown are the mean clinical score +/− SEM. Panel F. B cell depletion in peripheral blood on day 20. Significant differences were determined using an unpaired t-test (*, p<0.05; **, p<0.01). These results are representative of at least two independent experiments with Rituximab and two experiments using the 1F5 anti-human CD20 mAb (data not shown).