What are the differences? Again, be specific

Question

What will be an ideal response?

Answer 1

Differences: (1) Mast cells bind IgE, whereas NK cells bind IgG. (2) Exocytosis of granules from mast cells occurs at random around the cell membrane. Exocytosis of granules from NK cells is highly polarized, focusing only on the target cell to minimize damage to neighboring cells. (3) IgE binds to Fc?RI with high affinity in the absence of antigen; mast cells become activated when antigen becomes available and binds to the receptor-bound IgE. NK cells bind IgG with low affinity, and bind IgG effectively only when it is already bound to multivalent antigen. (4) Activated mast cells release inflammatory mediators (histamine and serotonin) that affect other cells, for example endothelium, causing increased vascular permeability and vasodilation. Activated NK cells release apoptosis-inducing compounds (perforin and granzyme/fragmentin) that kill target cells directly. (5) Antibody-dependent cell-mediated cytotoxicity (ADCC) carried out by NK cells could be induced in newborn infants by maternal IgG acquired transplacentally. IgE cannot be transferred across the placenta, and so newborn babies cannot activate mast cells via maternal IgE.