What are the effects of leukotriene B4 (LTB4)?

Leukotriene B4 (LTB4) is a potent pro-inflammatory mediator primarily involved in the recruitment and activation of neutrophils at sites of inflammation. One of its major effects is neutrophil chemotaxis, where it acts to attract neutrophils to inflamed tissues. Additionally, LTB4 enhances the adhesion of neutrophils to the endothelium, facilitating their migration out of the bloodstream and into the tissues where they can engage in immune responses.

This ability to promote both chemotaxis and adhesion is critical for the overall inflammatory response, particularly in acute inflammation and infection, where neutrophils play a key role in combating pathogens. LTB4 is produced by various cell types, including mast cells and macrophages, in response to inflammatory stimuli, underscoring its central role in the immune response.

In contrast to the correct answer, the other choices reflect different actions of other mediators. For example, while some leukotrienes can induce bronchoconstriction, LTB4 specifically is more focused on neutrophil activity rather than direct effects on airway smooth muscle or vasculature. Understanding the distinct functions of different leukotrienes aids in grasping their roles in the inflammation process.