BIOL-242 Chapter Notes - Chapter 21: Immunogenicity, Hapten, Antigen
20 May 2020
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Chapter 21. 3 | antigens are substances that trigger the. Antigens // substances that can mobilize the adaptive defense. Infectious organisms include bacteria, viruses, fungi, and other parasites. Most antigens are large, complex molecules that are foreign (not normally present in the body. Complete antigens // have two important functional properties: Immunogenicity // the ability to stimulate specific lymphocytes to proliferate (multiply) Reactivity // the ability to react with the activated lymphocytes and the antibodies released by immunogenic reactions. A large range of foreign molecules can act as complete antigens; proteins, many large polysaccharides, some lipids, and nucleic acids. Pollen grains and microorganisms like bacteria, fungi, and virus particles, are all highly allergenic because on their surface they have many different foreign macromolecules. Hypersensitivities // when small molecules link up with the body"s own proteins and the adaptive immune system thinks the combination is foreign and mounts an attack that is harmful, not protective. Small molecules include peptides, nucleotides, and hormones.
