Immune System Adaptation to Rapid Changes in Bacteremia

Abstract

Analogous to sepsis, relapsing fever (RF) borreliosis is a rapidly progressive and at times fatal infection of blood and tissues caused by different Borrelia species. RF offers a valuable opportunity to study the adaptation of the mammalian immune system to rapid changes in pathogen load due to the rapid appearance and disappearance of large numbers of bacteria from the circulation The purpose of the present study was to investigate how the immune system adapts to the rapid changes in pathogen load that take place before, during, and after bacteremia in immunocompetent mice. The course of bacteremia varies depending of the initial inoculum and the genetic background. The kinetics on specific antibody production depends of the initial inoculum. The anti‐inflammatory cytokines response is fundamental at the time of high pathogen load. The chemokine responses are different on each period of bacteremia but are command by CCL2, CXCL10 and CXCL13. Cells from the innate immune system play an important role during the first peak bacteremia in the acute infection. The results identified the key molecular and cellular immunological events that play a leading role during the various phases of bacteremia in this model.