Identifying innate immune receptors causing production of inflammatory cytokines by infection of Francisella tularensis

Abstract

Francisella tularensis is a pathogenic species and a causative agent of tularemia. This bacterium is incredibly infectious and often lethal in that F. tularensis causes the overproduction of pro-inflammatory cytokines. The objective of this study is to identify the innate immune receptors responsible for the production of inflammatory cytokines in response to F. tularensis infection. The study uses an immortalized C57BL/6 Bone Marrow Macrophage (BMMac) cell line as the control and knockout BMMac that are deficient in various innate immune receptors. The cells are passaged and seeded before infecting them with F. tularensis for 2 hours. The cells are treated with a high dose of gentamicin for 2 hours followed by a low dose of gentamicin for an incubation period of 24 hours. The supernatant from these cells are then collected and analysis processed by ELISA, an enzyme-linked immunosorbent assay, to measure production of inflammatory cytokines. These data were compared with the positive control of wild type BMMac and the negative control of uninfected BMMac cells. Analysis of these mutants reveal the involvement of innate immune receptors in triggering the pro-inflammatory cytokine storm in response to F. tularensis infection that leads to death of the host.