Functional analysis of a novel mutation in the CD70 gene leading to primary immunodeficiency disease

Official URL: https://risc01.sabanciuniv.edu/record=b2486372 _(Table of contents)

Immunity is the broad definition that embodies all protective mechanisms employed by the body against pathogens. T cell activation is central to a functional immune response, as T cells are fully activated by antigen-specific-interactions, co-stimulation, and instructive cytokines, according to the three-signal hypothesis. Primary immunodeficiencies (PIDs) are the heterogenous group of congential immune system defects that result in either partial or complete loss of immune responses against pathogens. Individuals with the PIDs are highly prone to recurrent infections. Epstein- Bar virus (EBV) is a ubiquitous oncogenic virus that is mostly asymptomatic, yet it can cause lymphoproliferative disorders (LPDs) in individuals with genetic defects. In this thesis, we identified a novel point mutation in the CD70 gene that leads to EBVassociated PID. The CD27/CD70 signalling pathway was previously shown to be responsible for the expansion and maintanence of EBV-specific CD8+ T cells, and humoral immunity. To analyze further, we generated stable cell lines through HIV-1 based lentiviral vector production, and transduction to transfer the wild-type and mutant CD70 proteins to K-562 and Namalwa cell lines. We performed cell surface and intracellular staining experiments to investigate wild-type and mutant CD70 gene products with flow cytometry. We also aimed to construct an in vitro functional assay employing CD27-Fc fusion protein production to evaluate the functionality of the identified CD70 mutations. Overall, we report a novel mutation in the CD70 gene that causes CD70 deficiency that can potentially contribute to the diagnosis of the suspected PID cases