immunology chapter 43. innate immunity present and waiting for exposure to pathogens non-specific...
TRANSCRIPT
Immunology
Chapter 43
Innate Immunity
Present and waiting for exposure to pathogens
Non-specific
External barriers and internal cellular and chemical defenses
Aquired Immunity
Specific
Develops after exposure
WBC’s involved in B and T cell immunity
Involve antibodies
Innate and Aquired Immunity
Innate Immunity – External Defenses
Skin
Mucous membranes
Cilia
Oil glands
Sweat glands
Stomach acid
Lysozyme in saliva, tears, and mucous
Innate Immunity – Cellular and Chemical Defenses
Phagocytosis
Antimicrobial proteins
Inflammation
Fever
Natural Killer Cells
Phagocytosis
Ingest invading organisms
Produce antimicrobial proteins and initiate inflammation
Ex: neutrophils, macrophages,, eosinophils, dendritic cells
Types of Phagocytes
Neutrophils- most abundant, ingest and destroy invadersMacrophages – found in spleen, lymphEosinophils – defend against parasites by secreting enzymesDendritic Cells – ingest microbes and are involved in development of aquired immunity
Lymph System Role in the Immune System
Antimicrobial Proteins
Complement system – composed of about 30 different microbial proteins which cause the lysis of the invading cell
Ex: interferon: fight against viral infections, secreted by virus infected cells that warn neighboring cells
Inflammatory Response
Heat, swelling, redness and pain
Caused by histamines that are released by damaged cells (cause vessel dilation)
Allows for more WBC and quicker clotting
Fever – allows for phagocytosis and increase killing of pathogen
Natural Killer Cells
Attack virus infected and body cells by releasing chemicals that cause cell death
Aquired Immunity
Humoral and cell mediated immunity
Macrophages secrete cytokines that activate the aquired immune system
Epitopes (antigenic determinants)
Antigen – molecule that causes an immune response, can be from a pathogen or another type of cell
Epitope – the antigentic determinant area, where the antibody will bond
Anitgen Recongition
2 types of lymphocytes (WBC’s) recongnize antigens – B and T cells
B cell have Y shaped molecules (AKA anitbodies or immunoglobulins) that are composed of 2 heavy chains and two light chains – the tips of the molecules are specific to different antigens (called the V region)
Anitbody Structure
T Cell Receptors
Recognize antigens that are bound to a normal cell protein called a MHC- major histocompatibility complexThe MHC binds with the antigen on the membrane of a normal cell – called antigen presentationClass I MHC – bind antigens of molecules formed in the cells (infected cells)- recognized by cytotoxic T cellsClass II MHC – bind antigens that have been internalized though phagocytosis (ex: dendritic cells and macrophages)- recognized by helper T cells
Lymphocyte Development
Lymphocytes that go to the thymus turn into T cells, while ones that develop in the bone marrow turn into B cells
When one of these cells encounters an antigen for the first time, it stimulates it activation and proliferation – call clonal selection
Lymphocyte Diversity
The specificity to antigens is vast
There are 1 million different V regions in B cells and 10 million different V regions in T cells all coded for by differential gene splicing
If a region is made that codes for one’s own body antigen it will be destroyed – this keeps self vs. non-self recognition
B and T Cell Development
Clonal Selection
Once a B or T cell has been activated it will form 2 clones
One clone will make effector cells (that will work to fight the antigen)
The other clone will make memory cells
Clonal Selection
Immunological Memory
Primary Immune Response – slow, must go through clonal selection
Secondary Immune Response – fast due to the presence of memory cells
Humoral Immunity
B cells
Make antibodies
Rely on helper T cells
Humoral Immune Response
Antibodies
Produced by B cells
5 different classes – differ only in their V regions
Bind to antigens causing viral neutralization, opsonization, or agglutination
Cell Mediated Immunity
Cytotoxic T cells - directly destroy certain cells or secretes chemicals that cause the destruction of cells
kill infected and cancerous cells
Rely on helper T cells
Humoral and Cell Mediated Activation
Continued…
Continued…
The Killing Action of Cytotoxic T Cells
Active and Passive Immunity
Active – permenant; caused by natural exposure or vaccines that lead to memory cells
Vaccine – weaken or dead pathogen
Passive – temporary; given through pregnancy, breast milk or anitbody injection
Self vs. Non Self
Blood Types
Organ Transplants
Blood Groups
Type O
Type A
Type B
Type AB
Rh Factor
Immune Diseases
Allergies
Autoimmune Diseases
Immunodeficiency Diseases ex: HIV/AIDS