Characterisation and ontogeny of dendritic cells

The bursa of Fabricius is the primary lymphoid organ of birds, where B lymphocytes differentiate and mature, learning to differentiate between self and non-self antigens. From the bursa mature lymphocytes migrate to secondary lymphoid organs, where they can recognise foreign antigens that enter the body. The bursa has become an important part of immunological research, as our current understanding of B cells is largely based on research on the avian bursa.

Dendritic cells (BSDCs) in the lymphoid follicles of the bursa of Fabricius, together with reticular epithelial cells, create a microenvironment that is essential for the development and terminal differentiation of B cells. Infectious bursitis is a severe immunosuppressive disease affecting young chickens caused by the IBD (infectious bursal disease) virus. The target site of infection is the bursa of Fabricius, where IBDV infection causes a breakdown of the follicular medulla, alteration of tissue structure and increased destruction of B lymphocytes. Based on our previous experiments, we hypothesise that BSDCs are the primary targets of the virus and therefore play an important role in IBDV infection.

Very little is known about the ontogenesis, differentiation and function of BSDCs, although their role in B-cell maturation and antigen handling is essential. Our work aims to follow the role and changes of BSDCs during normal and pathological development of the bursa of Fabricius. Currently, we have three antibodies, presumably membrane antigen-recognizing antibodies, that label BSDCs and other dendritic cells. We aim to understand the tissue distribution, cellular localisation, molecular mass, ontogenetic appearance, behaviour during viral infection and possible roles in regeneration after acute involution of these antibody-recognised proteins.

Objectives:

  1. To characterize novel specific markers recognizing the secretory dendritic cells (BSDC) of the bursa of Fabricius. To study the ontogenesis of follicular dendritic cells and Langerhans cells in avian embryonic models.
    (Methods: immunocytochemistry, immunoelectron microscopy, Western blot)
  2. Isolation and in vitro culture of avian dendritic cells, implementing phenotypic and functional studies.
    (Methods: cell culture, immunocytochemistry, flow cytometry, in situ hybridization)
  3. Monitoring of BSDCs and elucidation of their role in immunosuppressive infections, characterisation of the internalisation of viral particles in dendritic cells
    (Methods: immunocytochemistry, confocal and electron microscopy)