A Flow Cytometry Study of the Binding and Stimulation Potential of Inactivated toward Dromedary Camel Leukocytes.

Surra, a wasting disease caused by , is one of the major animal health burdens in camel-rearing countries, imposing significant economic losses due to reduced fertility and high mortality rates. The present study used inactivated (from the Card Agglutination Test for Trypanosomes/; CATT/) and flow cytometry to investigate their binding and activation potential toward camel leukocyte subsets. Labeling with propidium iodide (PI) enabled their flow cytometric enumeration and identification with forward scatter (FSC; indicative for cell size) and side scatter (SSC; indicative for cell internal complexity) characteristics that are comparable with values reported for . The incubation of PI-labeled non-opsonized with camel leukocyte populations revealed that camel monocytes have the highest potential to bind , followed by granulocytes and lymphocytes. The identification of pattern recognition receptors (PRRs) on camel immune cells and the pathogen-associated molecular patterns (PAMPs) in that are responsible for this different binding capacity requires further studies. Stimulation of camel neutrophils with induced shape change, reactive oxygen species (ROS) production, and neutrophil extracellular traps (NET)-formation. To ensure that , in the parasite concentration used in this study, is not apoptotic or necrotic to camel leukocytes, we evaluated cell apoptosis and necrosis after stimulation with . The results revealed no impact of stimulation for 2 h on the cell viability of camel leukocytes. Subsequent work may focus on the diagnostic employment of labeled and flow cytometry for the detection of anti- antibodies in camel serum. In addition, more efforts should be deployed to investigate the host-pathogen interaction mechanisms and the escape mechanisms of in camels. To complete these data, further studies using the living or freshly killed parasites could also be implemented in camels and/or horses.