SIRPA and infection: The same increases in tumor cell CD47 expression were not apparent following infection in vivo; however, increased baseline expression of tumoral CD47 was observed compared to tumor cells grown in vitro. This may be attributed to the presence of immune selection pressures in vivo, which are absent in vitro. Since CD47 expression is linked to inflammation, the CD47/SIRPα signaling axis stands to impact the efficacy of numerous immunotherapies.