Work Package 4
Analyzing avian T cell development and function during infection: Insights from chicken TCR knockout models
αβ and γδ T cells are central components of the avian adaptive immune system and play a crucial role in the defense against pathogens such as Marek's disease virus (MDV) and low pathogenic avian influenza virus (LPAIV). To improve the protection against these diseases in chickens, it is important to better understand the specific functions of these T cell subpopulations. By using state-of-the-art CRISPR/Cas9-mediated gene knockout technology, we aim to assess the distinct roles of αβ- and γδ-T cells in the immune defense and thus gain important insights into their contribution to adaptive immunity.
The importance of the β-chain of T cell receptor in chickens lies not only in the formation of T cell receptor (TCR), but also in its essential role in thymic development through the formation of a pre-TCR. Therefore, deletion of the β-chain results in a severe phenotype in chickens. We hypothesize that knocking out the α-chain of the TCR results in healthy knockout chickens that completely lack αβ-T cells. To answer this question, we generate TCR Cα-knockout chickens and characterize them phenotypically to decipher the difference between α- and β-chain knockout and enable detailed analysis of the αβ T cells in chickens. The newly generated TCR Cα-KO chickens will then be used to study the function of αβ T cells in MDV infection.
Avian influenza, a highly mutagenic viral infection in birds, leads to significant economic losses and has a high zoonotic potential. Previous studies have shown that γδ T cells in mice play a central role in the immune response against influenza A viruses. However, the role of γδ T cells in influenza infections in the natural host, the chicken, remains unclear. To investigate the immune response and survival of birds lacking γδ T cells, we will infect TCR Cγ KO chickens with LPAIV compared to wild type chickens. Furthermore, adoptive transfer of primed mCherry+ γδ T cells into TCR Cγ KO chickens that are subsequently infected with LPAIV will determine the role of γδ T cells in immunity against LPAIV. The proposed experiments will specify the importance of the different TCR chains for the development of the chicken immune system. In addition, we will elucidate the role of αβ T cells in MDV infection and the function of γδ T cells in the context of low pathogenic avian influenza.