The activity of the immune system against foreign substances (antigens).
The development by the body of antibodies specific for a particular disease.
Defense reaction of the body whereby an invading substance—an antigen, such as grafted tissue, a transplanted organ, bacteria, virus, or fungus—is recognized as foreign and antibodies specific against the antigen are produced to neutralize and/or destroy it. There are two basic kinds of immune response: humoral, mediated by B lymphocytes or B cells (chiefly against bacterial invasion), and cell- mediated, involving T cells (chiefly against viral and fungal invasion and transplanted tissue).
The body’s defense against a foreign substance, or antigen, that has entered or been introduced into the system. In an immune response, the immune system examines antigens and, under normal conditions, identifies them as “self” or “non-self.” Non-self cells are attacked and destroyed by antibodies produced by certain lymphocytes in response to a specific antigen on the surface of the non-self cell. When a faulty or mistaken identification is made, the immune response may be activated against self cells, resulting in autoimmune disorders.
The body’s reaction to foreign antigens so that they are neutralized or eliminated, thus preventing the diseases or injuries these antigens might cause. It requires that the body recognize the antigen as “non-self,” or foreign. There are several major components to the immune response. The nonspecific immune response, or inflammation, is the response of the body’s tissues and cells to injury from any source (e.g., trauma, organisms, chemicals, ischemia). As the initial response of the immune system to any threat, it involves vascular, chemical, and white blood cell activities. The specific immune response, involving T cells and B cells, is a reaction to injury or invasion by particular organisms or foreign proteins. The cell-mediated immune response refers to the activity of T lymphocytes (T cells) produced by the thymus in response to antigen exposure. Without T cells, the body cannot protect itself against many disease causing microbes. The loss of T cells in patients with acquired immunodeficiency syndrome (AIDS), for example, leads to infections with many opportunistic microbes that would otherwise be relatively well tolerated by persons with intact cellular immunity. T-cell activity also is the basis for delayed hypersensitivity, rejection of tissue transplants, and responses to cancers. The humoral immune response refers to the production of antigen-specific antibodies by plasma B lymphocytes (B cells); antibodies attach to foreign antigens in the bloodstream, helping to inactivate or remove them.
The reaction of the immune system against foreign substances in the body.
A bodily response, regulated by the immune system, which entails the generation of specialized antibodies to combat distinct foreign substances or agents known as antigens.
The immune response is the body’s defense mechanism against microorganisms, cancer cells, transplanted tissue, and any other substances or materials identified as antigenic or foreign. It involves the production of lymphocytes, which are specialized cells, as well as antibodies or immunoglobulins. Additionally, various substances and cells work together to eliminate the antigenic material and protect the body from potential harm.