Overcoming the histocompatibility barrier: transferrins as carriers and modulators of immunogenic identity

Proteic molecules were found in the bone marrow that were later identified as transferrins. When applied to transplantation of genetically incompatible bone marrow in supralethally irradiated recipient mice, the transferrins obtained from plasma of bone marrow donors promoted engraftment, permanent hemopoietic chimerism, and donor-type immune character. A combination of donor-matched transferrins and antigens was needed for induction of xenogeneic (interspecies) "tolerance" or unresponsiveness to donor antigens in chemically immunosuppressed mice treated with human transferrins and donor leucocytes. This novel and unique property of transferrins may explain the genesis and maintenance of immunogenic identity and allow a reshaping of the immune system.