I have made the bone marrow chimeras from the B6.MHC-II KO bone marrow into B6.WT mice (6.5x106 T-cell depleted BM cells). The chimerism was sucessfull as the irradiated control died 9-12 post-irradiation (9 Gy). The mice were given Baytril (antibiotic) for 2 weeks post--transplantation.

However after one and a half months post-transplantation the MHC-II KO BM chimeras started loosing weight, whereas the WT BM controls maintained their weight. These chimeras do not show any sign of GvHD or infection. Now they are around day 80 post-transplantation but the mice are still not gaining weight.

Do the MHC-II KO BM chimeras behave in this way or should I be doing anything different!