WALKER BIOLOGY CLUB MEETING & GUEST SPEAKER!! Dr. Janice Swab, a world-traveling evolutionary biologist will be speaking! Come hear about “Following Darwin [and not following Darwin] in the Southern Hemisphere!” January 23, 2008 5:00 p.m. in Room 210 Pizza & Drinks Provided!
Announcements • Topics for paper due today! • Pick a number • When signing up for your topic announce to the class what it is so that they know what has been taken. • Begin literature search! • Locate a minimum of 1 review article & 2 peer reviewed research articles. • Type out a reference list & have a copy of the papers turned in by Feb 4! • Worth a 10 pt quiz grade.
Innate Immunity An Overview
What PRProteins & receptors are on the Mf? • Mf Mannose Receptor: • C-type Lectin (PRP) • Binds mannose, N acetylglucosamine, & fucose residues on pathogen surface molecules.
Scavenger Receptors: • Group of @ least 6 molecular forms. • Recognize lipoproteins on Gm + & Gm – bacteria. • Involved in elimination of old & apoptotic cells. • Glucan receptor- • Dectin-1: C-type lectin (PRP) • Binds b-glucans (LPS)
LPS Receptor • Works with the Toll Like Receptors to stimulate cytokine production in the macrophage. Toll Like Receptors- - Recognize different component of pathogens. - Associates with other receptor & involved with signal transduction. • CR3- Opsonization.
How do phagocytes kill the pathogens? • 1. Acidification of the phagosome- ATP Synthase If activated, the mf will undergo a respiratory burst & phago-lysosomal fusion occurs.
2.Oxygen dependent killing mechanisms: • A) Enzymes to make Reactive oxygen radicals (ROIs): • NADPH oxidase- phagosomal membrane • Multicomplex protein. • Reduction of O2 superoxide anion (O2-): • SOD: converts superoxide to H2O2 • Myeloperoxidase- lysosomal protein • Produces Hypochlorous acid (OCl-) & Hydroxyl Radicals.
B) Reactive Nitrogen Intermediates (RNIs). • nitric oxide synthetase (NOS): • NO can be easily converted to peroxynitrite anion & nitrogen dioxide. NADPH NADP
3. Oxygen-Independent Killing mechanisms: Hydrolytic enzymes: Lysozyme Proteases RNases & DNases. Defensins: cationic peptides (cysteine); 29-35 AA. Competitors- Lactoferrin- compete cells for iron
1- Increase in vascular diameter. 2- Increase in vascular permeability 3- Endothelial cells activated to express adhesion molecules. inflammation.