Which substance is produced by macrophages that helps to kill pathogens?

Macrophages play a crucial role in the immune response, particularly in recognizing and eliminating pathogens. One of the key substances produced by macrophages that aids in combating infections is reactive oxygen species (ROS). These are chemically reactive molecules that include free radicals like superoxide and hydrogen peroxide.

When macrophages encounter pathogens, they can engage in a process known as oxidative burst, whereby they produce a surge of reactive oxygen species. These molecules are highly effective at damaging the cellular components of pathogens, disrupting their metabolism, and ultimately leading to their destruction. The production of ROS is a fundamental part of the innate immune response, allowing the body to respond quickly to infections.

Histamine, prostaglandins, and bradykinin, while important in various aspects of immune response and inflammation regulation, do not have the same direct pathogen-killing properties as ROS do. Histamine primarily plays a role in allergic reactions and dilation of blood vessels, prostaglandins are involved in inflammation and pain signaling, and bradykinin is a peptide that contributes to vasodilation and pain regulation. Therefore, the primary mechanism of pathogen destruction linked to macrophages is through the generation of reactive oxygen species.