AvrA effector protein of Salmonella enterica serovar Enteritidis is expressed and translocated in mesenteric lymph nodes at latestages of infection in mice

GIACOMODONATO MN; NOTO LLANA, M; AYA CASTAÑEDA MR; BUZZOLA FR; SARNACKI SH; CERQUETTI, MC

MICROBIOLOGY-UK

SOC GENERAL MICROBIOLOGY

Año: 2014 vol. 160 p. 1191 - 1199

1350-0872

Salmonellosis is a major health problem worldwide.  SalmonellaEnteritidis has been a  primary cause of  Salmonellaoutbreaks in many countries. AvrA is an SPI-1 effector protein involved in the enteritis pathway with critical roles in inhibiting inflammation  and apoptosis.  In this work, we constructed an AvrA-FLAG-tagged strain of Salmonella Enteritidis to analyze the expression profile of AvrA in vitro, in cell culture and in vivo.  AvrA expression and secretion were observed in vitro under culture conditions that  mimic intestinal and intracellular environments. In agreement, bacteria isolated from infected cell monolayers expressed and translocatedAvrA for at least 24 h post  inoculation. For in vivo experiments, BALB/c mice were inoculated by the natural route  of infection with AvrA-FLAG strain. Infecting bacteria and infected cells were  recovered from mesenteric lymph nodes. Our results  showed that AvrA continues to be  synthesized in vivo up to day 8 post inoculation.  Moreover, AvrA translocation was  detected in the cytosol of cells isolated from lymph nodes 8 days after infection.  Interestingly, we observed that AvrA is secreted byboth T3SS-1 and T3SS-2. In  summary, these findings indicate that AvrA expression is not constrained to the initial  host bacteria encounter in the intestinal environment as defined previously. AvrA effector may participate also in systemic Salmonella Enteritidis infection.