The presence of GBS in systemic organs at P3 was associated with increased IL-1β and IL-6 (Figure 4(b, c)), which are associated with both clinical GBS disease and rodent models of GBS infection.31,32 Flow cytometric analysis of the lungs of P3 pups revealed a significant increase in the proportion of Ly6G+ neutrophils, including antigen-experienced MHCII+ neutrophils (Figure 4(d, e)) compared to uninfected pups, suggesting vertical transmission of GBS and resulting EOS disease is associated with pneumonia-like disease. This evidence concerns the gene IL6 and susceptibility to pneumonia measurement.