SIRPA and neoplasm: Anti SIRPα antibody expression. In order to disrupt the tumour cell CD47 interaction with SIRPα of macrophages, oncolytic poxvirus VV expressing a chimeric molecule that consists of the ectodomain of SIRPα and the Fc domain of IgG4 (SIRPα-Fc-VV) was engineered [172].