How do neutrophils act as a cellular barrier to pathogens in humans?
Neutrophils contain granules that has toxic substances which inhibit the growth of pathogens. These are often the first defence cells that reach the site of infection. These attack pathogens by initiating a process called respiratory burst during which strong oxidising agents such as hydrogen peroxide, hypochlorite and so on are produced. This is how neutrophils form a barrier against pathogens.