In Vitro Determination of Canine Immunological Responses Due to Exposure to Recombinant Wolbachia Surface Protein

Abstract

Dirofilaria immitis is the causative agent of heartworm disease in several hosts, including dogs and cats. Like other filarial parasites, D. immitis harbors a strain of Wolbachia pipientis, an obligate, intracellular, Gram-negative bacterium found in many arthropods and nematodes. During heartworm treatment, Wolbachia is released and may play a role in the host inflammatory response. I analyzed the immune response elicited from five heartworm positive dogs and three heartworm negative dogs when exposed to recombinant Wolbachia surface protein (rWSP). ELISA results indicated that heartworm positive dogs had developed antibodies specific to rWSP due to previous exposure to Wolbachia. When stimulated by rWSP, lymphocytes from heartworm positive dogs produced primarily IFN-γ, IL-4, and IL-12, with trends suggesting that increased concentrations of rWSP induce immunosuppression. Overall, in the present study, cytokine profiles did not indicate rWSP incited heartworm positive dogs to elicit an inflammatory response.