Evaluation of the cellular immune response in naturally infected cattle with Mycobacterium avium spp. paratuberculosis from Argentina

MOYANO RD; ROMERO MA; ALVARADO PINEDO, F.; GRAVISACO M. J.; SANTANGELO MP; TRAVERIA GE; ROMANO MI

Nantes

Congreso; 13th International Colloquium on Paratuberculosis (ICP 2016); 2016

International asociation for paratuberculosis

Introduction: Mycobacterial infections represent major health problems, both in humans and farm animals. Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of Johne_disease in ruminants such as cows and sheep causingchronic intestinal inflammation. Exposed animals enter a subclinical period of 2 to 5 years after which a proportion of the infected animals develop severe enteritis with chronic diarrhea.Objectives. Study the T lymphocytes response in naturally infected cattle with MAP in order to detect infection or protection markers.Materials and Methods. 9 female calves, born in a naturally infected dairy herd with MAP, were sampled over a period of 18 months. 9 female calves were sampled from a free TB and PTB herd as control. Blood samples and fecal material were collected every two months. The presence of MAP in positive fecal cultures was confirmed by amplification of the MAP specific IS900 by qPCR. Peripheral blood T lymphocytes (CD4+CD25+, CD8+CD25+, WC1+CD25+) stimulated for 24h with a protein extract of Mycobacterium avium (PPD-a,BOVIGAM®), were evaluated by flow cytometry.Results. The presence of MAP in fecal cultures was confirmed in 5/9 animals from the positive herd by qPCR with primers IS900 at 14 months of age. This result was accompanied by a high response of gamma-delta and CD8+ cytotoxic lymphocytes. The cytokines profile was evaluated by RT-qPCR, resulting in an increase of IFNg in 2 of the animals at 16 months of age. These preliminary studies could contribute to the development of new diagnostic techniques and the identification of infection or protection markers.