SipA, SopA, SopB, SopD and SopE2 effector proteins of Salmonella enterica serovar Typhimurium are synthesized at late stages of infection in mice

GIACOMODONATO MN, UZZAU S, BACCIU D, CACCURI R, SARNACKI SH, RUBINO S, AND CERQUETTI MC.

MICROBIOLOGY-UK

SOC GENERAL MICROBIOLOGY

Lugar: Spencers Wood, UK; Año: 2007 vol. 153 p. 1221 - 1228

1350-0872

Salmonella pathogenicity island-1 (SPI-1) is essential for invasion of non-phagocytic cells whereas SPI-2 is required for intracellular survival and proliferation in phagocytes. Some SPI-1 effectors however, are induced upon invasion into both phagocytic and non-phagocytic cells, suggesting that they may also be required post invasion. In the present work we analyzed the presence of SipA, SopA, SopB, SopD, and SopE2 effector proteins of Salmonella enterica serovar Typhimurium in vitro and in vivo during the murine salmonellosis. Tagged (3xFLAG) strains of Salmonella enterica serovar Typhimurium were inoculated intraperitoneally or intragastrically to BALB/c mice and recovered from spleen and mesenteric lymph nodes of moribund mice.  Tagged proteins were detected by SDS-PAGE and immunoblotting with anti FLAG antibodies.  In vitro experiments showed that SPI-1 effector proteins SipA, SopA, SopB, SopD and SopE2 are secreted under SPI-1 conditions.  Interestingly, it was found that Salmonella enterica serovar Typhimurium continued to synthesis SipA, SopB, SopD and SopE2 in colonized organs for several days, regardless the route of inoculation.  Altogether, these results indicate that SPI-1 effector proteins may participate in the late stages of Salmonella infection in mice.