Basic analyses of proteins of interest for xenotransplantation

Proteins are the focus of numerous xenotransplantation studies because they provide structure and function to the graft. Their presence, absence, or even a functional incompatibility among species can compromise the long-term functioning of the xenograft. In particular, many cell-surface and soluble proteins, such as cytokines and chemokines, are involved in triggering rejection. For this reason, the identification and characterization of key proteins for xenografting, of either pig or human origin, are very important. Understanding their role in the xenogeneic setting can set the bases for the development of genetic engineering approaches that prolong graft survival and ensure function. There are multiple ways of determining and attaining protein expression, as well as studying protein interactions. In this chapter, we describe some basic techniques that allow us to detect and characterize pig and human proteins in order to better understand the molecular bases of rejection and function of pig xenografts.