Final answer:
Complement proteins amplify the inflammatory reaction by binding to mast cells and triggering the release of histamine, which is an important mediator in the inflammatory process, causing vasodilation, increased blood flow, and swelling.
Step-by-step explanation:
Certain complement proteins amplify the inflammatory reaction because they can bind to mast cells and trigger histamine release. Mast cells, found in connective tissue proper, contain many cytoplasmic granules that have the chemical signals histamine and heparin. When activated, as with the IgE-primed mast cells, these cells release granules and powerful chemical mediators such as histamine, which plays a crucial role in the inflammatory process, causing symptoms like vasodilation, increased blood flow, and swelling at a site of injury or infection. This histamine release is part of a larger inflammatory response that can include the release of other mediators such as leukotrienes, prostaglandins, and cytokines. However, in the context of this question, which specifically asks about the triggering of mast cells by complement proteins, the correct answer is histamine.