Assessment of lymphocyte development in radiation bone marrow chimeras.

The Basic Protocol utilizes congenic strains of mice that differ at the CD45 (common leukocyte antigen) locus. Bone marrow-derived cells from these strains of mice can be identified by monoclonal antibodies specific for the two allelic variants of the CD45 molecule. Because this antigen is expressed on all nucleated blood cells, it provides a convenient genetic marker for following the progeny of transplanted bone marrow cells. Transplantation of marrow between mouse strains congenic for CD45 after lethal irradiation establishes hematopoiesis driven by genetically marked cells in recipient animals. The first support protocol can be used to establish appropriate radiation doses for use in the Basic Protocol. After several weeks, peripheral blood or primary and secondary lymphoid organs of transplant recipients can be evaluated for the presence of donor-derived cells using the second support protocol. Two- or three-color flow cytometry can be used to identify the progeny of transplanted cells, to document their cell-surface phenotypes, and to follow development of T, B, and myeloid lineages in vivo.