How do reactive oxygen species kill pathogens?

ROS can kill pathogens directly by causing oxidative damage to biocompounds or indirectly by stimulating pathogen elimination by various nonoxidative mechanisms, including pattern recognition receptors signaling, autophagy, neutrophil extracellular trap formation, and T-lymphocyte responses.

Do immune cells release ROS?

High local concentrations of ROS are produced by immune cells to kill pathogens [4], while the much higher concentration of ROS can damage cellular components such as proteins, lipids, and nucleic acids [5].

How do cells deal with reactive oxygen species?

Under normal physiological conditions, cells control ROS levels by balancing the generation of ROS with their elimination by scavenging systems. But under oxidative stress conditions, excessive ROS can damage cellular proteins, lipids and DNA, leading to fatal lesions in the cell that contribute to carcinogenesis.

What is ROS immune system?

Reactive oxygen species (ROS) are a group of highly reactive chemicals containing oxygen produced either exogenously or endogenously. ROS are related to a wide variety of human disorders, such as chronic inflammation, age-related diseases and cancers.

What reactive oxygen products are used in the lysosome to kill the pathogens?

Reactive oxygen species (ROS) such as superoxide, hydroxyl radical, and hydrogen peroxide appear to be essential agents for killing microbes within the phagolysosome.

How are reactive oxygen species ROS generated?

Reactive oxygen species (ROS) are generated during mitochondrial oxidative metabolism as well as in cellular response to xenobiotics, cytokines, and bacterial invasion. Oxidative stress refers to the imbalance due to excess ROS or oxidants over the capability of the cell to mount an effective antioxidant response.

Does oxidative stress effect immune system?

Oxidative stress can cause chronic inflammation. Infections and injuries trigger the body’s immune response. Immune cells called macrophages produce free radicals while fighting off invading germs. These free radicals can damage healthy cells, leading to inflammation.

What is consumed by PMNS during respiratory burst?

Immunity. This is an important aspect of the innate immunity. Respiratory burst requires a 10 to 20 fold increase in oxygen consumption through NADPH oxidase (NOX2 in humans) activity. NADPH is the key substrate of NOX2, and bears reducing power. Glycogen breakdown is vital to produce NADPH.

How can ROS reduce reactive oxygen species?

The reduction of oxidative stress could be achieved in three levels: by lowering exposure to environmental pollutants with oxidizing properties, by increasing levels of endogenous and exogenous antioxidants, or by lowering the generation of oxidative stress by stabilizing mitochondrial energy production and efficiency.

How do lysosomes kill bacteria?

Lysosomes destroy bacteria by the hydrolytic enzymes present in them. E.g. a macrophage engulfs bacteria by phagocytosis and then fuses with lysosomes, where the pathogen is destroyed by hydrolytic enzymes.

How does the phagolysosome kill pathogens?

Phagolysosomes function by reducing the pH of their internal environment thus making them acidic. In human neutrophils, the phagolysosomes destroy pathogens also by producing hypochlorous acid.