A state of host‐mediated resistance defending against foreign agents or organisms encountered on or within the tissues that is capable of distinguishing between self and nonself.
Nonsusceptibility to the invasive or pathogenic effects of foreign microorganisms or to the toxic effect of antigenic substances.
The ability to resist infection and to heal. The process may involve acquired immunity, the ability to learn and remember a specific infectious agent, or innate immunity (the genetically programmed system of responses that attack, digest, remove, and initiate inflammation and tissue healing).
The power that a person may acquire to resist an infection to which most other people are susceptible.
The ability to resist attacks of a disease because antibodies are produced.
The process whereby antibodies are developed to specific antigens.
In medicine, the state of being unaffected by or unsusceptible to a disease because the body’s immune system is operating effectively specifically because antibodies are present to fight off the disease organisms. Babies are born with natural immunity from antibodies they have received from their mother’s bloodstream, reinforced during breastfeeding, which wears off during the first year of life. In centuries past, this meant that a child one year old lacked internal defenses against some of the most serious diseases, so infant mortality was high. But in this century, vaccines have been developed to give children an acquired or induced immunity that allows them to survive attack by various disease organisms.
Specific antibody elaborated in response to artificial or natural stimuli such as vaccination or infection.
State of being not susceptible to a particular disease. Immunity may be natural, or innate, or it may be acquired during life (e.g., as a result of infection or vaccination).
The body’s ability to defend itself against potentially harmful foreign substances and cells called antigens. Immunity invokes the immune response, which includes both nonspecific and specific components. It initially activates nonspecific immune responses followed by highly specific responses that are exactly matched to the specific threats presented. Immunity is associated with the body’s defense against disease causing agents, problems with organ transplants and blood transfusions, and diseases resulting from an overreaction to antigens, such as occurs in autoimmune disorders, and underreaction, such as with aids (acquired immunodeficiency syndrome).
The body’s ability to resist infection, afforded by the presence of circulating antibodies and white blood cells. Antibodies are manufactured specifically to deal with the antigens associated with different diseases as they are encountered. Active immunity arises when the body’s own cells produce, and remain able to produce, appropriate antibodies following an attack of a disease or deliberate stimulation. Passive immunity, which is only short-lived, is provided by injecting ready-made antibodies in antiserum taken from another person or animal already immune. Babies have passive immunity, conferred by antibodies from the maternal blood and colostrum, to common diseases for several weeks after birth.
The condition of being immune or insusceptible to an agent. The term is most often used in regard to resistance to infectious disease-immunity to smallpox, diphtheria, colds, acquired immunodeficiency syndrome (AIDS), and the like. However, one may also speak, for example, of “stress immunity,” the ability to resist stress, or “cold immunity,” the ability to withstand cold. Immunity is relative, in that almost any immunity may be overwhelmed by either (1) a massive attack (such as contamination of a wound by barnyard dirt loaded with tetanus) or (2) a general lack of resistance, often referred to as “immunodeficiency” (an emaciated, starving person is unlikely to resist pneumonia); the combination of a massive attack and lack of resistance makes infection even more likely.
The body’s defence against foreign substances such as bacteria, viruses and parasites. Immunity also protects against drugs, toxins and cancer cells. It is partly non-specific that is, it does not depend on previous exposure to the foreign substance. For example, micro-organisms are engulfed and inactivated by polymorphonuclear leucocytes as a first line of defence before specific immunity has developed.
Protection from diseases, especially infectious diseases.
The ability of the body to destroy and resist infection.
The body’s ability to destroy pathogens that it has previously encountered before they are able to cause disease.
The state of being unencumbered by sickness or ailment is the result of either lacking traits that allow for the propagation of pathogenic agents, or possessing or obtaining traits that hinder their harmful effects. Furthermore, being impervious to the assault of a pathogenic organism or virus is the outcome of either lacking traits that align with their prerequisites or possessing or acquiring supplementary traits that are detrimental to their existence (APS).
The condition of being resilient against illness. Typically, most infants possess a natural immunity to infectious diseases within their initial two to three weeks of life, which they inherit from their mother. Some individuals seem to have an inherent resistance to specific bacteria-related illnesses, but it can be challenging to confirm whether they have never experienced a mild episode of the sickness that may have gone unnoticed as a case of the “flu.”