BIOM 250n 1st Edition Lecture 17Outline of Last Lecture I. InflammationII. FeverIII. The Complement SystemIV. Interferons Outline of Current Lecture I. Antimicrobial PeptidesII. Adaptive ImmunityIII. Antibody TypesIV. B CellsCurrent LectureI. Antimicrobial Peptides (AMPs)a. Peptides between 12-50 amino acids longi. Broad spectrum of targets: bacteria, fungi, viruses, parasitesii. Recognize common sugar or protein molecules on the surface of microbesb. Methods of action:i. Form pores in target plasma membrane and lyses cellii. Can also bind/activated LPS and remove it from circulationiii. Can activate immune cells or recruit them to site of infectionII. Adaptive Immunitya. Has specific defense against a targeti. First encounter with a pathogen initiates a slow-developing specific responseii. Develops a memory against this previously encountered organismiii. Memory response is faster than initial adaptive responseb. Adaptive immunity has two components: humoral and cellularc. Humoral immunity:These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.i. Based on production of antibodies against antigens from a specific pathogenii. Antibodies produced by B cellsiii. B cells also produce memory cells that wait for the next exposure to the initial pathogend. Cellular immunity:i. Based on action of T cellsii. Some T cell types act to recognize target and signal other immune cellsiii. Another type, cytotoxic T lymphocytes (CTLs) can bind to and kill pathogens or diseased cellsIII. Antibody Typesa. Also called immunoglobulin classesb. IgG: monomeri. Cross placenta and confer passive immunity to infantii. Easily cross from bloodstream to tissuesiii. Activate complementc. IgM: pentameri. 5 monomers joined gives 10 binding sitesii. Multiple sites can cause clumping of cells/virusesd. IgA: dimeri. Can enter then pass through a mucosal cellii. Important component of mucus, binds to pathogens, prevents attachment of pathogen to mucosal surfaceIV. B cellsa. B cells make antibodyi. Each individual B cell and its clones make one specific antibodyii. This antibody is displayed on the cell’s surface to bind antigeniii. If an antigen binds it is taken into the cell, digested and the antigenic portion is displayed on the B cell surface—an antigen present celliv. The antigen is presented by a glycoprotein called the Major Histocompatibility Complex (MHC)v. This is what our cells use to tell self from non-self cellsvi. Once an antigen is displayed in MHC on a B cells surface then other immune cells can bind to that antigen and activate the B cellb. Activation and clonal selection:i. Activated B cells:1. Only the B cell that can bind a specific antigen can be activated2. Activated cell multiplies3. Some cells differentiate into antibody-producing plasma cells4. Others differentiate into memory cellsii. Plasma cells usually start producing IgMc. What an antibody does to a pathogen:i. Agglutination: ability of an antibody to cause clumping of the pathogenii. Opsonization: coating of pathogen with antibodies—enhances phagocytosisiii. Activation of complement: antibody attracts complement and induces lysisiv. Neutralization: coating of structures on bacteria inhibits adherence; coating of toxins prevents them from getting to their target or attacking