Human neutrophil antigens (HNAs) are a group of 5 glycoproteins that are expressed on human neutrophils, and in some cases, also on other cells and tissues. Endogenous antibodies against HNAs have been implicated in cases of alloimmune neonatal neutropenias, autoimmune neutropenias, febrile transfusion reactions and transfusion-related acute lung injury (TRALI). The availability of mAbs to HNAs permits the use of solid phase assays to detect endogenous antibodies specific to these antigens. While mAb reagents against HNA-1, HNA-2, HNA-4 and HNA-5 antigens are available, there are not yet any mAbs available for HNA-3. This project aims to develop mAbs against the two alleles of HNA-3 that can then be used to develop cell-based assays to detect anti-HNA-3a and anti-HNA-3b antibodies in blood donors. Furthermore, this project aims to use the anti-HNA-3 mAbs in existing in vitro transfusion models to help understand the mechanisms by which TRALI develops.