Dynamic changes of Foxp3(+) regulatory T cells in spleen and brain of canine distemper virus-infected dogs.

Canine distemper virus (CDV) infection causes immunosuppression and demyelinating leukoencephalitis in dogs. In viral diseases, an ambiguous function of regulatory T cells (Treg), with both beneficial effects by reducing immunopathology and detrimental effects by inhibiting antiviral immunity, has been described. However, the role of Treg in the pathogenesis of canine distemper remains unknown. In order to determine the effect of CDV upon immune homeostasis, the amount of Foxp3(+) Treg in spleen and brain of naturally infected dogs has been determined by immunohistochemistry. In addition, splenic cytokine expression has been quantified by reverse transcriptase polymerase chain reaction. Splenic depletion of Foxp3(+) Treg was associated with an increased mRNA-expression of tumor necrosis factor and decreased transcription of interleukin-2 in the acute disease phase, indicative of disturbed immunological counter regulation in peripheral lymphoid organs. In the brain, a lack of Foxp3(+) Treg in predemyelinating and early demyelinating lesions and significantly increased infiltrations of Foxp3(+) Treg in chronic demyelinating lesions were observed. In conclusion, disturbed peripheral and CNS immune regulation associated with a reduction of Treg represents a potential prerequisite for excessive neuroinflammation and early lesion development in canine distemper leukoencephalitis.

Species-specific properties and translational aspects of canine dendritic cells.

Dogs are affected by spontaneously occurring neoplastic and inflammatory diseases which often share many similarities with pathological conditions in humans and are thus appreciated as important translational animal models. Dendritic cells (DCs) represent the most potent antigen presenting cell population. Besides their physiological function in the initiation of primary T cell responses and B cell immunity, a deregulation of DC function is involved in immune-mediated tissue damage, immunosuppression and transplantation complication in human and veterinary medicine. DCs represent a promising new target for cancer immunotherapy in dogs. However, the therapeutic use of canine DCs is restricted because of a lack of standardized isolation techniques and limited information about dog-specific properties of this cell type. This article reviews current protocols for the isolation and in vitro generation of canine monocyte- and bone marrow-derived DCs. DCs of dogs are characterized by unique morphological features, such as the presence of cytoplasmic projections and periodic microstructures. Canine DCs can be discriminated from other hematopoietic cells also based on phenotypic properties and their high T cell stimulatory capability in mixed leukocyte reactions. Furthermore, the classification of canine DC-derived neoplasms and the role of DCs in the pathogeneses of selected infectious, allergic and autoimmune diseases, which share similarities with human disorders, are discussed. Future research is needed to expand the existing knowledge about DC function in canine diseases as a prerequisite for the development of future therapies interfering with the immune response.