Antibody-mediated inhibition of the human alloimmune response to platelet transfusion in Hu-PBL-SCID mice

Severe combined immune deficient (SCID) mice were engrafted with human (Hu) peripheral brood lymphocytes (PBL) from a previously alloimmunized donor a nd transfused with HLA-mismatched platelets. We have previously shown this to be a useful model for platelet transfusion. These engrafted mice (Hu-PBL -SCID mice) produced high levels of alloantibody in response to standard pl atelet preparations. However, when the first platelet challenge was presens itized with anti-HLA antibody and then transfused there was a marked reduct ion in the amount of alloantibody produced to Eve subsequent untreated plat elet transfusions, Platelets pretreated with platelet-specific anti-HPA-la (PLA1) sera did not induce a decrease in the anti-HLA alloantibody response . This demonstrated that platelet-induced HLA alloimmunization can be block ed by anti-HLA antibody-sensitized cells.