Tolerance to class I major histocompatibility complex antigens in chicken B cell chimeras. Effect of B cell depletion on transferability of tolerance

摘要

AbstractB cells from bursa of Fabricius of newly hatched chickens are able to reconstitute the B cell compartment of chemically bursectomized chickens. The resulting B cell chimerism can be detected with monoclonal antibodies against donor B cell alloantigen. Chimeric chickens accept donor‐type skin grafts and are unresponsive to donor major histocompatibility complex (MHC) antigens in graft‐vs.‐host splenomegaly assay and mixed lymphocyte reaction. To study the capability of B cells to induce tolerance to selected MHC antigens, we transplanted class I or total MHC‐incompatible bursa cells into cyclophosphamide‐treated recipients. The recipients of class I or total MHC‐incompatible bursa cells were equally tolerant of donor‐MHC antigens. To further analyze the mechanisms of tolerance to class I antigensvs.total MHC, spleen cells from tolerant chickens were transferred to irradiated, histocompatible secondary hosts. The secondary recipients were also unresponsive to bursa cell donor‐strain MHC antigens. However, if the chimeric B cells were depleted before the spleen cell transfer, the transfer of tolerance to total MHC was severely inhibited. Instead, most recipients of B cell‐depleted spleen cells tolerant of class I antigens were still tolerant of bursa cell donor MHC. Our results indicate differences in the transferability of tolerance to class I antigensvs.entire MHC, although in primary recipients of bursa cells the tolerance is similar. These data suggest that a mechanism that is not dependent on the presence of donor cell chimerism contributes to the maintenance of tolerance to donor class I antigens. The transfer of tolerance to total MHC disparity requires the presence of chimeric cells indicating that donor alloantigen expression is needed for induction of tolerance in th