The effects of leukocyte's RNA-binding proteins on the immune responses of dogs infected with canine parvovirus.

BACKGROUND: Canine parvovirus (CPV) is a highly contagious virus that can lead to severe clinical complications in dogs. RNA-binding proteins (RBPs) play a crucial role in regulating translation and stabilizing RNA. Due to the failure of the immune system to respond effectively in dogs infected with CPV, this study aimed to investigate various immunological markers in CPV-infected dogs and to evaluate the impact of RBPs from these infected dogs on immune responses. Blood samples were collected from both healthy and parvovirus-infected dogs. Parvovirus infection was confirmed using immunochromatographic kits. Monocytes were isolated, and exosomes were extracted from these cells and other leukocytes. RBPs were isolated from the leukocytes of parvovirus-infected dogs using Fe-nanoparticles conjugated to RNA. The delivery of RBPs into monocytes and leukocytes was achieved through exosomes. Subsequently, the activities of anti-protease, lysozyme, myeloperoxidase, survival rates, and the expression some of the inflammatory response genes were assessed in the recipient cells. RESULTS: Dogs with acute CPV exhibited significantly lower specific antibody titers and comparable total immunoglobulin levels, along with reduced lysozyme and myeloperoxidase activities in their leukocytes compared to asymptomatic dogs. A significant effect of exosomes and RBPs were observed on lysozyme activity, myeloperoxidase levels, and leukocyte survival. The expression of interferon-gamma (IFN-γ) (16.4-fold) and NOX2 (7.61-fold) was significantly elevated in monocytes treated with RBPs compared to untreated cells. Additionally, no viral proteins were found in RBPs extracted from infected animals. CONCLUSIONS: The RBPs from infected dogs demonstrated a compensatory role in regulating immune responses in infected animals, rather than mediating immune regulation by CPV through RBPs. These findings enhance our understanding of the immune response alterations in dogs affected by parvovirus infection, the role of RBPs in this process, and the potential development of novel therapeutic approaches.