Question Video: Comparing Nonspecific and Specific Immune Responses Biology

Video Transcript

How does the nonspecific immune response compare to the specific response to antigens? (A) The nonspecific response is slower than the specific immune response. (B) The nonspecific response is faster than the specific immune response. (C) The nonspecific response provides protection against future infections but the specific response does not. Or (D) the nonspecific response produces more memory cells than the specific immune response.

This question asks us for the difference between two types of immune responses which work together to help protect the body from pathogens and substances that appear harmful. Pathogens are biological agents that cause illness or disease. These biological agents include viruses and the microorganisms bacteria, fungi, and protists. There are two forms of our immune system. Their names, specific and nonspecific immune systems, give us an idea about the differences between them. So let’s review these before taking another look at our question.

The nonspecific immune response is also called the innate immune response since it is present from the time you are born. “Innate” means inborn. It protects against all pathogens and other foreign and potentially harmful substances in the same way without specifically targeting one. There are many examples of nonspecific immunity, for instance, the skin, which acts as a physical barrier between the body’s tissues and all pathogens from the outside world.

Other parts of the body which provide a nonspecific immune response include the cough and vomit reflexes, enzymes in tears, skin oil, mucus, and stomach acid. There are also phagocytic cells that engulf pathogens by a process called phagocytosis, shown here in the diagram. These also contribute to specific immunity by presenting pathogens to lymphocytes.

If the nonspecific immune system defends against all pathogens and other potentially harmful substances in the same way, how about the specific immune system? Let’s have a look.

Before we explain how the specific immune system works, we need to familiarize ourselves with the term “antigen.” Antigens are substances that when recognized as nonself by the immune system will trigger an immune response. Examples of antigens are pollen, toxins, and substances on the surface of pathogens or other foreign cells. When talking about the nonspecific response earlier, we said it defended against pathogens and other harmful substances. Well, these contain antigens that trigger the response.

The specific immune system tailors its attack to a specific antigen. It is also known as the acquired or adaptive immune system, as it has to build the immunity up over your lifetime, as it encounters new antigens. This immune system involves the B and T lymphocytes. When these first encounter an invading antigen, they have to be activated, clonal selection, before they can proliferate and produce a population big enough, clonal expansion, to destroy the antigen.

B lymphocytes produce antibodies against the antigen, to help prevent it from damaging the body further. T lymphocytes have four main roles, which depend on the type of T lymphocyte. The roles can be activating other immune cells, destroying infected cells, producing cytokines, or closing the whole attack down once the antigen has been destroyed.

Once the cells of the specific immune response have encountered an antigen, they produce memory cells which remain in the body to fight future infections against the same antigen. Because the specific immune system requires the body’s cells to recognize foreign antigens and activate other cells that aid in immunity, it can take anywhere between five and 10 days for specific immune responses to occur. On the other hand, nonspecific immunity responds immediately and usually causes symptoms of infection that you are familiar with like fever.

After reviewing the differences between specific and nonspecific immune responses, we can return to our question and narrow down our choices.

We now know that it is only the specific immune response that produces memory cells. So we can rule out options (C) and (D). We also know that the specific immune response requires time for recognition and proliferation of immune cells in response to an antigen, while the nonspecific immune response is almost immediate.

Therefore, the correct answer to our question “how does the nonspecific immune response compare to the specific response to antigens?” is answer choice (B). The nonspecific response is faster than the specific immune response.