Dataset_Inactivation of the <i>porB</i> gene reduces the virulence of <i>Neisseria meningitidis</i> in transgenic mice

This study used transgenic mice expressing human transferrin to compare the virulence of carriage and invasive meningococcal isolates by following the outcome of infection after intraperitoneal infections by these meningococcal isolates. Clinical scores (fur quality, strength, and temperature) and bacterial load in blood were measured to determine bacterial virulence. Inflammatory cytokines were determined in blood. The invasive isolates provoked significantly more severe infections compared to the carriage isolates. Carriage isolates of <i>porB</i> class 3 were significantly less virulent than the invasive isolates of <i>porB</i> class 2 or 3. An invasive PorB- isolate caused milder infections than its parental isolate. This study confirms the ability of invasive isolates of N. meningitidis to cause more severe infection than carriage isolates in transgenic mice, and suggests that <i>porB</i> expressed in invasive isolates seems to contribute to their higher virulence compared to carriage isolates.