Anatomy-Immune System

Phagocyte:

(non-specific defense) -WBC that wanders through the blood engulfing and dissolving any pathogens and foreign particles or wastes

Cells of the Immune System:

-Effector Cell: any fully differentiated cell of the immune system that attacks foreign substances -Cytotoxic T Cells (killer t Cells): Cellular immune response: directly destroy cells that have been infected with viruses, tumor cells, and cells of transplants -Effector Helper T Cells: (bind to antigen and secrete signals that invoke cell and humoral immune response) involved in activating both B and T lymphocytes -Memory Cells: both B and T cells that are set aside to attack if specific pathogen shows up in the future -Effector B Cells: (plasma cells) make and secrete antibodies

Specific Immune Response: Adaptive

-Immune responses that are specific for certain pathogens 1. Once a virus or bacteria has invaded and been destroyed then the body has an immunity to that specific pathogen (The body has what is called a "memory")

The Immune Reaction:

-Lymphocytes (WBCS) produce antigen-binding receptors (antibodies) known as immunoglobulin-these antibodies bind to the antigens -Different lymphocytes produce different antibodies

Cells Continued:

-MHC markers: major histo-compatible complexes (reognition proteins on the plasma membrane of body cells) -Interleukins: signaling proteins also known as cytokines -Apoptosis: programmed cell death -Cellular Response: Cytokines: are any of a number of small proteins that are secreted by specific cells of hte immune system which carry signals locally between cells, and thus have an effect on other cells. Proteins, peptides, or glycoproteins.

Clonal Selection:

-Process in which naive B-cell produces many clones of itself some becoming plasma cells and some Memory B cells -Part of the "humoral response" also called B-memory cells, are B-lymphocytes that are transported by the blood plasma and produce large volumes of antibodies

Non-Specific Defenses:

-Work against a variety of foreign substances and pathogens a.Skin and mucous b.Inflammation c.Interferons d.Phagocytes e.Fever

Specific Defenses:

-Work against very specific molecules and pathogens a.Antibody production b.Lymphocytes T-Cells

Non-specific chemical defenses:

-lysozyme -complement -interferons -defensins

Second Line of Defense:

-phagocytes -antimicrobial chemicals -inflammation and fever

The body's first line of defense:

-skin -mucous membrane -normal microbiota -body secretions

Opsonin:

Molecules that act as a binding enhancer for the process of phagocytosis, especially antibodies which coat the negatively charged molecules on the membrane

T-Memory Cell:

Part of the "cellular response" are T-Lymphocytes that are involved in the secondary immune response

Macrophage:

Phagocytic cells involved in both specific and nonspecific immune response

Third LIne of Defense:

Specific Immunity -antigens

Two Major Groups of Defenses In the Body:

Specific and Nonspecific

Epitope:

Specific sequence of amino acids on an antigen

Paratope:

Specific sequence of amino acids on the antibody that recognizes the epitope on the antigen

Humoral Response (in the body fluids):

Steps: 1.Macrophae engulfs antigen and chops it up and presents it on its surface 2.Naive B-cells become activated by contact with helper T cells antigen 3.Activated Cells clone themselves and... 4.Differentiate into either memory b cells or plasma cells 5.Primary response: antibody production can take up to 2 weeks (usually get sick and then recover) 6.Secondary response: memory cells produce mass amounts of antibodies rapidly, wiping out the pathogen before illness occurs -Plasma cells produce mass amounts of antibodies and live for about 4 to 7 days -Memory b cells can live for many years

Steps of a macrophage ingesting a pathogen:

a.Ingestion through phagocytosis, a phagosome is formed b.The fusions of lysosomes with the phagosome creates a phagolysosome; the pathogen is broken down by enzymes c.Waste material is expelled or assimilated

Secondary Response:

a.The second time an antibody is exposed to an antigen there is only a 2 to 7 day lag before the peak in antibody concentration

Primary Response:

a.Upon initial exposure to an antigen that a body has never been exposed to, there is a 10 to 17 day lag before the peak in antibody concentration b."primary immune response"

Internal Nonspecific:

i.Inflammation: brings blood cells to help combat foreign bodies 1.occurs where skin or mucous membranes have been injured -The wound attracts mast cells found in most organs-these cells release histamine which is an amino acid derivative that causes heat redness and swelling -Reason: increases blood to area which brings in phagocytes which engulf foreign matter then die and become puss ii. Fever: release of pyrogens produced by macrophages (faster proliferation of wbcs) 1.Infected areas feel hot 2.When body is infected phagocytes release proteins called pyrogens iii.Interferons: protein produced by an infected cell that disrupt viral replication

External Nonspecific:

i.Skin 1.Epidermal cells: -sloughed off -always being repaired and replaced 2.Chemical defenses of the skin -oils and wax -sweat (acidic) -Glands (sebaceous glands) 3.Mucous Membranes: -Nose, mouth, vagina, respiratory system -traps bacteria in mucous which contains lysozyme enzyme which kills bacteria

Antibody and Immunoglobulin:

1.Found in the blood and tissue fluids, as well as many secretions 2.Structure, they are large y-shaped globular proteins. In mammals there are five types of antibodies 3.Each immunoglobulin class differs in its biological properties and has evolved to deal with different antigens. This is called specificity 4.Antibodies are synthesized and secreted by plasma cells that are derived from the B-lymphocytes cells of the immune system

Humoral vs. Cellular Response:

1.Humoral Response (HIR): refers to a immune specific response in the blood (secreted antibodies in plasma) b-lymphocytes 2.Cellular Response: refers to a immune specific response in a cell (T-lymphocytes) -The invading pathogen is identifies and phagocytized by a macrophage

5 major types of antibodies:

1.IgA antibodies are found in areas of the body such as the nose, breathing passages, digestive tract, ears, eyes, and vagina 2.IgG antibodies are found in all body fluids 3.IgM antibodies are the largest antibody 4.IgE antibodies are found in the lungs, skin, and mucous membranes. They cause the body to react against foreign substances 5.IgD are antibodies found in small amount sin the tissues that line the belly or chest

The immune system contains three types of antigen presenting cells (APCS)

1.Macrogphages 2.Dendritic cells 3.B Cells

Humoral Response Review:

1.Plasma cells are just one method the body uses to fight diseases. Each plasma cell produces a particular antibody to neutralize a particular antigen 2.When an antigen enters the body, they must first bind to a B cell which then proliferates to form plasma cells 3.The plasma cells then secrete antibodies that inactivate the pathogen and mark it for destruction. Normally, a plasma cell will produce antibodies for four to five days and then will die 4.When a new antigen enters the body, some time is needed until the body can develop antibodies to fight them.

The Immune Response has 3 Features:

1.Specificity: specific antibody to antigen 2.Recognition: naive b cells recognize and differentiate 3.Memory: memory cells hang around for years and immediately produce antibodies upon recognition The binding of the antigen to receptors on the lymphocyte triggers the lymphocyte to produce clones (clonal selection) of itself. Therefore the next attack on the body by this pathogen is wiped out before the body gets sick

Humoral Response Review Continued:

5.Naive B cells will first have to be activated in order to be able to respond to a specific disease causing agent. The antigen itself does this while it is flowing through the body. 6.When it encounters a naive b cell, it will bind to it and help trigger clonal selection 7.Clonal selection is the process by which activated B cells multiply in order to form several clones of itself. Some of these clones become plasma cells. The plasma cells are then able to produce antibodies against the disease causing agent. 8. Some clone cells, however, do not form plasma cells but memory cells. These memory can last in the body for years. Their purpose is to provide a quick response to the antigen should it appear in the body in the future.

Antibody:

A globular protein produced by the body that recognizes a specific antigen

Agglutination of Microorganisms:

Agglutination is mainly a function of antibodies with multiple reactive FAB sites such as IgM and IgA. The antibodies link microorganisms together so they can be filtered out of the lymph and blood and be phagocytosed more effectively by the fixed macrophages of the mononuclear phagocytic system

Antigen:

Any object or molecule the body perceives as foreign

B-Memory Cell:

Differentiated from Naive B-Lymphocytes

Plasma Cell:

Differentiated from Naive B-lymphocytes

Pathogen:

Disease causing organism

Immunoglobulin:

Glycoproteins that function as antibodies

Naive B Cell (B-lymphocytes)

Hasn't come in contact with an antigen that will trigger clonal selection