Journal of Vaccines & Vaccination

Neutrophil-associated disruption of the granulomatous response in BCG-vaccinated mice exposed to environmental mycobacteria

16^th Euro Global Summit and Expo on Vaccines & Vaccination

June 19-21, 2017 Paris, France

Marcela Henao-Tamayo, Brendan Podell and Ian Orme

Colorado State University, USA

Posters & Accepted Abstracts: J Vaccines Vaccin

Abstract:

Multiple studies over the past 20-30 years have concluded that exposure to mycobacteria widely distributed in the environment [EM] can often subvert the efficacy of the BCG vaccine. A variety of possibilities have been proposed to explain this phenomenon, and here we provide a new hypothesis. In the studies reported here we demonstrate that exposure of mice to Mycobacterium avium, given periodically over a prolonged period of time in drinking water can sensitize these animals and establish a low grade infection in the lungs. A consequence of this is the gradual accumulation of certain T cell subsets, principally TH17 cells and a smaller number of -TCR+T cells, in the lungs of these animals. After challenge with a Beijing strain of M. tuberculosis acquired protective TH1 immunity developed in a normal manner, but the ability of EM-exposed BCG-vaccinated mice to control the growth of the infection was severely impaired. Examination of the lung pathology indicated that large numbers of neutrophils accumulated in the lungs of the EM-exposed mice, causing substantial �??spatial disruption�?� of the normal granulomatous response. We hypothesize that the establishment of TH17 cells in the lungs of these animals prior to the challenge results in the recruitment of this disruptive neutrophil influx, and studies to directly test this possibility are now underway.

Biography :

Email: marcela.henao_tamayo@colostate.edu