Cx/BMT-treated mice display an increased rate of reconstitution and subsequent increased cellularity, with no alteration in autoreactivity. (A) Peripheral blood of Cx/BMT and BMT-only groups were analyzed by flow cytometry for the donor CD45.1 congenic cell surface marker expression. By week 2 after BMT, Cx/BMT mice demonstrate a significantly higher donor presence than BMT-alone groups and remained higher until week 4 after BMT, when the BMT-only mice achieved similar levels of chimerism. (B) Untreated EAE mice had a significantly reduced cellularity in the thymus, with irradiation conditioning in the BMT-only group inducing even further thymic atrophy. By contrast, castration overcame the degenerative effects of EAE and irradiation. (C) Similar results were seen in the spleen. (D,E) Whereas the general T-cell proliferative capacity did not differ between groups, MOG_35-55–specific proliferation of mice treated with either BMT only or BMT in combination with castration was significantly reduced in comparison with untreated groups. Results are expressed as mean plus or minus SEM from 2 or more independent experiments. *P < .05 versus normal young; #P < .05 versus BMT alone; **P < .01 versus normal young; ##P < .01 versus BMT alone; ∧P < .05 versus EAE alone; and $P < .001 versus all groups.