Evaluation of the effect of saliva and plasma exosomes of domestic cats (Felis catus) on feline leukemia virus (FeLV) infected cells in vitro

• Grant number: 16/06755-1
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: May 20, 2016
• End date: August 21, 2016
• Field of knowledge: Agronomical Sciences - Veterinary Medicine
• Principal Investigator: João Pessoa Araújo Junior
• Grantee: Claudia Filoni
• Supervisor: Regina Hofmann-Lehmann
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Institution abroad: University of Zurich (UZH), Switzerland
• Associated to the scholarship: 13/12253-0 - Characterization of exosomes in plasma and saliva of domestic cats (Felis catus) and evaluation of their innate immune defense role against infection with Feline leukemia virus (FeLV), BP.PD

Abstract

Feline leukemia virus (FeLV) is an exogenous, horizontally-transmissible, worldwide naturally occurring retrovirus of the domestic cat (Felis catus) and some wild felids. Most cats (approximately 60%) mount an effective immune response against the virus and present a regressive FeLV infection outcome. In approximately 30% of infected cats, the virus establishes persistent infection (progressive infection). A minor proportion of cats (approximately 10%) develop atypical outcomes. There is currently no method available to predict which cats are potentially regressors or highly susceptible to FeLV before exposure to the virus. Exosomes are are circular fragments of membrane containing bioactive molecules that are actively released from the endosomal compartment and are involved in a broad range of biological processes, including immunological activities. We hypothesize that the effectiveness of innate immune defense as conferred by delivered exosomes in saliva of cats at the main entry site of FeLV - the oropharyngeal mucosa - might play a relevant role in determining the susceptibility of cats to FeLV. Exosome preparations from cat saliva and plasma from three groups of cats - a control group, a group of FeLV infected and healthy cats (regressors) and a group of FeLV infected and clinically ill cats (progressors), according to previous diagnostic tests performed in Brazil - will be sent to Switzerland for performing interference assays using feline QN10s cells. Microscopic description and measurements of FeLV viral load (RNA) in supernatants and FeLV proviral load (DNA) will be performed using qPCR and RT-qPCR. Plasma samples from all cats will be tested by indirect ELISA to confirm the categories of infection of each cat. (AU)