antigen


antigen
antigenic /an'ti jen"ik/, adj.antigenically, adv.antigenicity /an'ti jeuh nis"i tee/, n.
/an"ti jeuhn, -jen'/, n.
1. Immunol. any substance that can stimulate the production of antibodies and combine specifically with them.
2. Pharm. any commercial substance that, when injected or absorbed into animal tissues, stimulates the production of antibodies.
3. antigens of a particular type collectively.
[1905-10; ANTI(BODY) + -GEN]

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Foreign substance in the body that induces an immune response.

The antigen stimulates lymphocytes to produce antibodies or to attack the antigen directly (see antibody;immunity). Virtually any large foreign molecule can act as an antigen, including those of bacteria, viruses, parasites, foods, venoms, blood components, and cells and tissues of various species, including other humans. Sites on the antigen's surface fit and bind to receptor molecules on the lymphocytes' surface, stimulating the latter to multiply and initiate an immune response that neutralizes or destroys the antigen.

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      foreign substance that, when introduced into the body, is capable of stimulating an immune response, specifically activating lymphocytes (lymphocyte), which are the body's infection-fighting white blood cells. Virtually any large foreign molecule can act as an antigen, including those contained in bacteria, viruses, protozoa, helminths, foods, snake venoms, egg white, serum components, red blood cells, and other cells and tissues of various species, including humans. An antigen that induces an immune response—i.e., stimulates the lymphocytes to produce antibody or to attack the antigen directly—is called an immunogen.

      On the surface of the antigens are regions, called antigenic determinants, that fit and bind to receptor molecules of complementary structure on the surface of the lymphocytes. The binding of the lymphocytes' receptors to the antigens' surface molecules stimulates the lymphocytes to multiply and to initiate an immune response—including the production of antibody, the activation of cytotoxic cells, or both—against the antigen. The amount of antibody formed in response to stimulation depends on the kind and amount of antigen involved, the route of entry to the body, and individual characteristics of the host.

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Universalium. 2010.

Look at other dictionaries:

  • antigen — ANTIGÉN s.n. Substanţă de natură proteică, determinând, la introducerea în organism, apariţia unui anticorp. – Din fr. antigène. Trimis de ana zecheru, 13.09.2007. Sursa: DEX 98  antigén s. n., pl. antigéne Trimis de siveco, 26.05.2005. Sursa:… …   Dicționar Român

  • antigen — (n.) substance that causes production of an antibody, 1908, from Ger. Antigen, from Fr. antigène (1899), from anti (see ANTI (Cf. anti )) + Gk. gen (see GEN (Cf. gen)) …   Etymology dictionary

  • antigen — antigen. См. антиген. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • antigen — àntigēn m DEFINICIJA biol. bilo koja supstanca koja u određenim uvjetima može inducirati specifičan imunološki odgovor i potaknuti stvaranje protutijela i senzibiliziranih T limfocita, s kojima onda reagira ETIMOLOGIJA anti + gen …   Hrvatski jezični portal

  • antigen — ► NOUN ▪ a harmful substance which causes the body to produce antibodies. DERIVATIVES antigenic adjective …   English terms dictionary

  • antigen — ☆ antigen [an′tə jən, an′təjen΄ ] n. [ ANTI + GEN] a protein, toxin, or other substance of high molecular weight, to which the body reacts by producing antibodies antigenic [an΄tijen′ik] adj …   English World dictionary

  • Antigen — Each antibody binds to a specific antigen; an interaction similar to a lock and key. An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then… …   Wikipedia

  • Antigen — Antigene (engl. für Antibody generating) sind Stoffe, an die sich Antikörper und bestimmte Lymphozyten Rezeptoren spezifisch binden können (wobei letzteres in der Regel bewirkt, dass die Produktion von Antikörpern gegen das Antigen angeregt wird) …   Deutsch Wikipedia

  • Antigen — An|ti|gen 〈n. 11; Biochem.〉 artfremder Eiweißstoff, der im Blut von Mensch u. Tier die Bildung von Antikörpern anregt [<grch. anti „gegen“ + genos „Art, Geschlecht“] * * * An|ti|gen [Kurzw. aus Antisomatogen (↑ anti griech. sõma = Körper; ↑… …   Universal-Lexikon

  • antigen — UK [ˈæntɪdʒ(ə)n] / US [ˈæntɪdʒən] noun [countable] Word forms antigen : singular antigen plural antigens medical a harmful substance that causes your body to produce antibodies to fight it …   English dictionary


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