IMMUNOLOGY

Detailed explanation-1: -The mast cell secretes histamine by exocytosis when it is stimulated immunologically by binding of a specific antigen to IgE molecules in the cell membrane. Histamine secretion may also be induced by non-immunological stimulators such as polymeric amines, neuropeptides and calcium-ionophores.

Detailed explanation-2: -So, the correct answer is ‘Mast cells’.

Detailed explanation-3: -Mast cells and basophils represent the most relevant source of histamine in the immune system. Histamine is stored in cytoplasmic granules along with other amines (e.g., serotonin), proteases, proteoglycans, cytokines/chemokines, and angiogenic factors and rapidly released upon triggering with a variety of stimuli.

Detailed explanation-4: -In the skin, antigens, via IgE, activate mast cells in the deep layers of connective tissue. Mast cells release histamine as well as other vasoactive molecules, which cause urticaria (hives). If the antigen activates mast cells in deeper tissue, this can lead to angioedema.

Detailed explanation-5: -Mast cells They’re an important part of the immune system and help fight infection. When mast cells detect a substance that triggers an allergic reaction (an allergen), they release histamine and other chemicals into the bloodstream. Histamine makes the blood vessels expand and the surrounding skin itchy and swollen.