The “immunity and inflammation” class (175 genes) is related to the inflammatory cascade after activation of leukocytes by LPS via TLR4 receptor (a receptor for bacterial lipopolysaccharide). TLR4 is a critical driver of immune responses to bacterial infections. Signals from TLR4 promote NF- κB and AP-1 activation, leading to inflammatory gene expression  (DEG for TLR4, TNF, JUNB, and NF-B pathway).