Do you want to make this class easier

Do you want to make this class easier? Do yourself a favor. Use the… Virtual Microbiology Classroom (VMC) ! The VMC is full of resources to help you succeed, including: • • practice test questions review questions study guides and learning objectives photos of bacterial colonies, stains, media and other lab-related material You can access the VMC through Moodle, or by going to www. Science. Prof. Online. com

Immunology Part 2: Specific / Acquired Lecture 11 pathogen Your T-cell Your WBC pathogens

Figure 15. 1

THIRD LINE OF DEFENSE ____, _____ or _____ Immunity • The body’s ability to recognize and defend itself against distinct invaders and their products – Is a “smart” system – “Memory’ allows it to respond rapidly to additional encounters with a pathogen - If nonspecific immune system has ‘warriors’, then specific immunity has more sophisticated ‘special agents’ and ‘assassins’. • _____ trigger specific immune responses • 2 Types of Specific Immunity – Naturally acquired- immune response against antigens encountered in daily life – Artificially acquired- response to antigens introduced via a vaccine

_____ • Body does not direct immune response against whole bacteria, fungi, protozoa or viruses. • Molecules trigger a specific immune response Antigenic particles are often associated with a specific characteristic of an organism, and therefore detected as foreign when they get inside another organism that doesn’t have that characteristic. • Include components of bacterial cell walls, capsules, pili, and flagella, as well as proteins of viruses, fungi, and protozoa • Food and dust can also contain antigenic particles • Enter the body by various methods – – – Through breaks in skin & mucous membranes Direct injection, as with a bite or needle Through organ transplants and skin grafts Hi! I’m Tami’s Cell Can I see your I. D. ? Hi! I’m Tami’s Cell Antigens

Antigens • The body recognizes antigens by three dimensional shapes on the antigen called _________, also known as epitopes. • Types of antigens: – ________: Toxins and other secretions and components of microbial cell walls, membranes, flagella and pili. – ________: Microbes that reproduce inside infected cells produce endogenous antigens. Can only be seen by the immune system if incorporated into the host cell’s plasma membrane. – ________: aka “self-antigens”. Antigen molecules found on an individuals normal, uninfected cells. (i. e. nametags saying “I am part of the body. ”) Antigen Epitope Ig See Figure 16. 1 in Chapter 16 of your book for an illustration comparing all three types of antigens. Antigens

______ • Also called immunoglobulins (Ig) • Proteinaceous molecules that bind ____ at the antigen-binding site. • Considered part of the humoral immune response since bodily fluids such as lymph and blood were once called humors Antibodies

How Antibodies Work • Some act as opsonins, ____ to identify antigens for phagocytes and stimulate phagoctosis. • Some work as _____ (i. e. they neutralize toxins for e. g. those causing diphtheria and tetanus) • Some attach to bacterial flagella making them less active and easier for phagocytes to engulf • Some cause ______ (clumping together) of bacteria making them less likely to spread But where do antibodies come from? Antibodies

______ System • Screens the tissues of the body foreign antigens • Composed of lymphatic vessels and lymphatic cells • One-way system that conducts lymph from local tissues and returns it to the circulatory system – Lymph is a liquid with similar composition to blood plasma. – Comes from fluid leaked from blood vessels into surrounding tissues • Lymph nodes house _____ that recognize and attack foreign antigens present in the lymph Lymphocytes

Lymphocytes • WBCs of specific immunity. The smallest leukocytes. Have huge nucleus surrounded by thin rim of cytoplasm. • Produced from blood stem cells in the red bone marrow. Two main types: • ____ mature in ______ then concentrate in lymph nodes and spleen • ____ mature in _____ • B and T cells mature then circulate in the blood and lymph. • Circulation ensures they come into contact with pathogens and each other. • B cells are a type of Antigen Presenting Cell. Lymphocytes

What Is an Antigen Presenting Cell? Consider your WBCs as a security force for your body and any non-self antigens as pictures of a bad guy. The larger the force, the more likely one of the officers will run into a “bad guy” and be able to apprehend it. But sometimes law enforcement needs backup or to work cooperatively in order to catch a criminal. (Think about the FBI putting a picture of a wanted criminal on INTERPOL … the International Criminal Police Organization). Any WBC that can grab and present an antigen to another, is called an ________ (APC). APCs include B cells, macrophages and dendritic cells. Antigen Presenting Cells

Major Histocompatibility Complex (MHC) • MHC is a collection of genes on chromosome 6, which code for major histocompatibility glycoproteins. • ______ proteins are in the plasma membrane of all your nucleated cells (non-professional APCs) • ______ proteins are found only in the plasma membrane B cells and special antigen presenting cells (professional APCs, such as macrophages and dendritic cells. ) • MHC glycoproteins function to hold and position antigenic determinants for presentation to other cells. (Think of them as antigen holders. ) • Some lymphocytes only recognize antigenic determinants that are bound to MHC molecules. Major Histocompatibilty Compex

B Lymphocytes (B cells) Activated B-lymphocytes produce either: ________ make antibodies to a pathogen. ________ remember the same pathogen for faster antibody production in future infections. B Lymphocytes

B Cell Receptors • Some antibodies are secreted by Plasma cells, others are attached to B cell membranes. • If attached to the B cell membrane, the antibody is called a ________ (BCR). • Surface of each -cell is covered by ~ 500, 000 identical B cell receptors. • Each BCR is complements a specific _______ that the body may or may not ever encounter (ex. rattlesnake venom proteins). • Your body has billions of B cells, each with BCRs for a different antigenic determinant. • Typically, B cells don’t initiate an immune response directly, but require the assistance of certain T lymphocytes. (BCRs) B Lymphocytes

T Lymphocytes (T cells) • Produced in red bone marrow and mature in thymus • Circulate in the lymph and blood and migrate to the lymph nodes (and other areas of the lymph system). • Part of the cell-mediated immune response because they act directly against various antigens – – Endogenous invaders (intracellular pathogens inside the body’s cells) Abnormal body cells such as cancer cells • Types – _______ or ____ T cells (TC) – ____ T cells (TH) Scanning electron micrograph showing the presence of the human immunodeficiency virus (HIV-1), (green spheres) on the surface of helper T lymphocyte. Public health Image Library 11279 T Lymphocytes

Cytotoxic T cells (TC Cells) • Also called Killer T cells. • Involved in _________________. • Directly kill cells of the body that are abnormal or infected with viruses and other intracellular pathogens. Some infectious agents can avoid antibodies by hiding inside our cells. Infected or mutated cells display foreign proteins and are marked for destruction by the Killer T Cells. These cells can kill a target several ways including initiation of apoptosis (cell suicide). From Microbiology & Immunology Online U of South Carolina: pathmicro. med. sc. edu/bowers/immune%20 cells. htm Animation: http: //bcs. whfreeman. com/thelifewire/content/chp 18/1802003. html T Lymphocytes

Helper T Cells (TH cells) Function to “help” regulate the activities of B cells and T C cells during an immune response. Secrete various protein messengers, called _____, that determine which immune response will be activated. Function of Helper T cells: Antigen presenting cells (APCs…mainly dendridic cells and macrophages) present antigen and Helper T cells recognize these. The activation of a resting helper T cell causes it to release cytokines and other stimulatory signals (green arrows) that stimulate the activity of macrophages, killer T cells and B cells, the latter producing antibodies. T Lymphocytes

T cell Receptors (TCRs) • T cell receptors, or TCRs, are molecules found on the surface of T lymphocytes (or T cells) that recognize antigens bound to major histocompatibility complex (MHC) molecules. • Interaction of the TCR with antigen and MHC molecules results in activation of its T lymphocyte through a series of biochemical events. T Lymphocytes

Cytokines • Regulatory proteins that act as intracellular signals and are released by certain cells in your body. • B cells and Cytotoxic T cells do not respond to antigens unless first signaled by cytokines. • Cytokines include: – _______ (ILs): ‘inter’ = between & ‘leukin’ = leukocytes. Signal among leukocytes. – _______ (IFNs): Antiviral proteins. – _________: Stimulate stem cells to divide. – ________ (TNFs): Macrophages and T cells secrete TNFs to kill tuor cells and regulate immune responses. – ________: Signal leukocytes to rush to the site of inflammation or infection, and activate other leukocytes. Cytokine Network

Humoral Immune Response • The ___________is called the humoral immune response. • The following steps are involved: – Antigen presentation: APC’s with antigenic determinants randomly encounter TH cells that have TCRs for those same antigenic determinants. – Helpers multiply: Those TH cells proliferate and bind to the MHC 2 glycoprotiens on B cells. – B cells activated: Activated TH cell secretes interleukin, activating the B cell so that it quickly multiplies and differentiates. – Antibodies produced: Plasma B cells rapidly produce large numbers of antibodies. This high level of activity means that these cells are short-lived. – Memory B cells can survive for years, ready to initiate antibody production of that particular antigen is encountered again. – Animation Humoral Immune Response: http: //bcs. whfreeman. com/thelifewire/content/chp 18/1802004. html Putting It All Together

Is this how you feel right now? Well, Here are some extra slides to help you Review.

What are antibodies? ________________________________ What type of cells make antibodies? ________________ What are antigens? ________________________________ What type of cell remembers antigens? ________________ 3 nd Line of Defense Specific or Acquired RECAP

3 nd Line of Defense Specific or Acquired How does our body eliminate intracellular viruses and abnormal human cells? ________________________________ What are the 2 different types of T-cells and the role of each? ________________________________ RECAP

Alphabet Soup • • • Ig BCR TCR APC IL IFN TNF MHC 1 MHC 2 RECAP

Do you want to make this class easier? Do yourself a favor. Use the… Remember, every class meeting adds pieces to the puzzle! Virtual Microbiology Classroom (VMC) ! The VMC is full of resources to help you succeed, including: • • practice test questions review questions study guides and learning objectives photos of bacterial colonies, stains, media and other lab-related material You can access the VMC through Moodle, or by going to www. Science. Prof. Online. com