Experimental evidence suggests that both transmaternal and direct antibiotic exposure of neonatal mice compromises CD8+ T-cell responses to Escherichia coli K-12 or Klebsiella pneumoniae-induced neonatal sepsis (37) and to viral pathogens such as vaccinia virus (34) or lymphocytic choriomeningitis virus (LCMV) and influenza virus (21). This evidence concerns the gene CD8A and Neonatal sepsis.