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

MÓNICA N. GIACOMODONATO, MARIÁNGELES NOTO LLANA, MARÍA DEL ROSARIO AYA CASTAÑEDA, FERNANDA R. BUZZOLA, SEBASTIAN H. SARNACKI, MARIA C. CERQUETTI.

MICROBIOLOGY-UK

SOC GENERAL MICROBIOLOGY

Lugar: London; Año: 2014 vol. 160 p. 1191 - 1199

1350-0872

Salmonellosis is a major health problem worldwide. Salmonella Enteritidis has been a primary cause of Salmonella outbreaks 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 translocated AvrA 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 by both 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.