Host Immune Response Paper
The host immune response to the attack
The immune response is activated the moment an infection is detected, neutrophils release antimicrobial substances viz. antimicrobial peptides, reactive oxygen species (ROS), reactive nitrogen species (RNS), protease and lysozymes. However, S. aureus presents a defense by releasing antioxidant enzymes like the catalase and superoxide dismutase which counteract ROS, RNS and their effects. The antimicrobial peptides have also been found to be neutralized and degraded by S. aureus. As a preventive measure S. aureus also destroys neutrophils through secretion of toxins. The bacteria further survives in the host by acquiring of nutrients from the host especially Iron (Fe). The major part of the iron (95%) is
segregated in the host cells and the serum iron is bound to the host proteins which cannot be accessed easily. However, when bacterium S. aureus experiences iron starvation, it secretes high affinity iron binding compound namely aureochelin and staphyloferrin and at times also activates a cascade of iron acquisition program enabling transport of iron complexes through the plasma membrane and degradation of heme. Conclusively, a severe bacterial infection, triggers the activation of the adaptive immune response to restrict the infection and also to prevent reinfection. However, S. aureus reinfects the host repeatedly throughout life by evading the adaptive immune response which is poorly understood currently (Liu, 2009. P-3-4).
The immune response is activated the moment an infection is detected, neutrophils release antimicrobial substances viz. antimicrobial peptides, reactive oxygen species (ROS), reactive nitrogen species (RNS), protease and lysozymes. However, S. aureus presents a defense by releasing antioxidant enzymes like the catalase and superoxide dismutase which counteract ROS, RNS and their effects. The antimicrobial peptides have also been found to be neutralized and degraded by S. aureus. As a preventive measure S. aureus also destroys neutrophils through secretion of toxins. The bacteria further survives in the host by acquiring of nutrients from the host especially Iron (Fe). The major part of the iron (95%) is
segregated in the host cells and the serum iron is bound to the host proteins which cannot be accessed easily. However, when bacterium S. aureus experiences iron starvation, it secretes high affinity iron binding compound namely aureochelin and staphyloferrin and at times also activates a cascade of iron acquisition program enabling transport of iron complexes through the plasma membrane and degradation of heme. Conclusively, a severe bacterial infection, triggers the activation of the adaptive immune response to restrict the infection and also to prevent reinfection. However, S. aureus reinfects the host repeatedly throughout life by evading the adaptive immune response which is poorly understood currently (Liu, 2009. P-3-4).