In which type of immune response do mast cells primarily participate?

Mast cells play a crucial role in Type I hypersensitivity, which is also known as immediate allergic reactions. These cells are a type of white blood cell that are found in various tissues throughout the body, particularly near blood vessels and mucosal surfaces. When an individual is exposed to an allergen, the mast cells recognize it and become activated. This activation leads to the degranulation of mast cells, resulting in the release of various mediators like histamine, leukotrienes, and cytokines. These substances cause the typical symptoms of allergic reactions, such as increased vascular permeability, smooth muscle contraction, and inflammation.

In Type I hypersensitivity reactions, the immune system mistakenly identifies a harmless substance as a threat and mounts an exaggerated response. This is different from cell-mediated immunity, which primarily involves T-cells and does not involve mast cells directly. Passive immunity, on the other hand, refers to the acquisition of antibodies from another source, and doesn't involve mast cells either. Humoral immunity is mediated by B-cells and antibodies. While mast cells have some interactions with B-cell activity, their primary involvement is in the immediate allergic response characteristic of Type I hypersensitivity.