Antigen-antibody reaction

Japanese: 抗原抗体反応 - こうげんこうたいはんのう（英語表記）antigen-antibody reaction

A phenomenon that occurs due to the specific binding of antigens and antibodies. It is also called an immune response. When a foreign substance, such as a microorganism or a foreign body, which is a non-self substance, enters the body, a protein called an antibody is produced in the body. A substance that has the property of reacting specifically with and binding to an antibody is called an antigen. Antibodies produced in the body in response to the stimulation of an antigen can be divided into humoral antibodies and cellular antibodies, but the former is usually referred to, and immunoglobulin Ig is responsible for this function. Types of antigen-antibody reactions include precipitation reactions, agglutination reactions, complement fixation reactions, immune adhesion reactions, and lysis reactions of bacteria and red blood cells. The biological reaction that occurs when a foreign antigen is recognized as non-self is stored in memory cells and responds to the invasion of non-self, so an infection defense mechanism is established in the body. Applying this principle, vaccinations are carried out by administering vaccines as antigens to prevent the invasion of bacteria and viruses. However, on the other hand, there is a risk of allergic reactions and anaphylaxis due to excessive reactions, and even the development of autoimmune diseases, and immunodeficiencies due to insufficient reactions. The rejection reaction of xenografts seen in organ transplants is also an example of this antigen-antibody reaction.

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

抗原 antigenと抗体 antibodyの特異的結合によって起る現象をいう。免疫反応ともいう。非自己の物質である外来の微生物や異物が体内に侵入した場合，生体の中に抗体という蛋白質がつくりだされる。抗体と特異的に反応して結合する性質をもった物質を抗原という。抗原の刺激によって生体内につくられる抗体は，体液性抗体と細胞性抗体に分けられるが，普通は前者をいい，免疫グロブリン Igがその機能をになっている。抗原抗体反応の種類としては沈降反応，凝集反応，補体結合反応，免疫粘着反応，細菌や赤血球の溶解反応などがある。外来性抗原を非自己と認識して起った生体反応は，記憶細胞に記憶され，非自己の侵入に対応するので，生体内には感染防御機構が成立する。この原理を応用して，抗原としてワクチンを接種して，細菌やウイルスの侵入を防ぐ予防接種が行われる。しかし反面，反応の過剰によるアレルギー反応やアナフィラキシー，さらには自己免疫疾患などの発症や，反応の不全による免疫不全症などを起す恐れもある。臓器移植にみられる異種移植を拒絶する拒否 (拒絶) 反応も，この抗原抗体反応の一つである。

出典　ブリタニカ国際大百科事典小項目事典ブリタニカ国際大百科事典小項目事典について　情報

<<: Epiphany - Kougensai (English spelling) Epiphany

>>: Kokenki - Kokenki