A nonspecific defense reaction to tissue damage caused by injury or infection is called what?

• A. Inflammatory response
• B. Vaccination
• C. Active immunity
• D. Passive immunity

Answer: (A)

The inflammatory response is the body's nonspecific defense to tissue damage or infection. When tissue is injured or invaded, cells release histamines and other mediators that cause blood vessels to dilate and become more permeable. This increases blood flow and allows immune cells, like neutrophils and macrophages, to reach the site, leading to redness, heat, swelling, and often pain. The purpose is to contain the damage, destroy invading microbes, and begin repair. This response is part of the innate immune system and does not rely on recognizing a specific pathogen, unlike vaccines or other adaptive immune mechanisms. Vaccination, active immunity, and passive immunity involve targeted, memory-based responses to particular antigens, so they are not the general, nonspecific reaction described here.