LO 4 Flashcards
Describe the Acquired Immune Response
- Defends the body against injury
- Has memory capability
- Responds faster than inflammatory response
- Involves complex network of white blood cells (WBCs)
- May result in increased level of tissue damage and disease as it fights pathogens
List examples of the body seeing parts of itself as invading antigens
- Tumor cells
- Cells infected with viruses
- Organ transplant
- Tissue graft
- Incompatible blood transfusion
- Cells of own body: Autoimmune diseases
Recognition of the body’s own antigens as invaders is known as ___________
Autoimmune disease
The overreaction to antigens is known as _________
Hypersensitivity
List the cells involved in autoimmune response
- Cytokines
- Lymphocytes - B-cell lymphocytes, T-cell lymphocytes, Natural killer (NK) cells
- Macrophages
- Dendritic cells
Describe B-Cell Lymphocytes
- Develop from stem cells in bone marrow
- Mature and reside in lymphoid tissue - Lymph nodes, tonsils, and other body tissue
- B cells travel to the site of injury when stimulated by antigen
- Produce and release a protein (antibody) in response to presence of antigen
- Circulating antibodies: Immunoglobulins (Ig)
- Two main types:
1. Plasma cell: Produces specific antibodies
2. B-memory cell: Retains the memory of previously encountered antigen and will clone itself in the presence of antigen
List the 5 types of immunoglobulins
- IgA
- IgD
- IgE
- IgG
- IgM
Describe the development of T-cell lymphocytes
- Develop from bone marrow stem cells
- Travel to the thymus and mature
List the types of T-cell lymphocytes
- Memory cells
- T-helper cells: Increase functioning of B cells
- T-suppressor cells: Turn off functioning of B cells
- T-cytotoxic cells: Attack virally infected cells or tumor cells
Describe the function of T-cell lymphocytes
- Increase the function of B cells: Enhancing the antibody response
- Carry the CD8 marker
- Active in surveillance against virally infected cells
- Directly attack virally infected and neoplastic cells
- Start, regulate, and coordinate the overall immune response
Describe Natural Killer (NK) Cells
- Destroy foreign cells
- Located within the microcirculation
- Active against viruses and cancer cells
- Activity can be abnormal as in HIV infection= relation to secondary cancer mortality
Describe macrophages
- Accessory cells in immune response
- Located in connective tissue (CT) during inflammation
- Function - Phagocytosis/Assist B cells and T cells
Describe the functions of macrophages
- Phagocytosis: engulf invader antigens and destroy
- Messenger between inflammatory response and immune response
- Activating factor: Produce and secrete lysosomal enzymes
- Amplify the immune response but do not have memory of the encountered antigen
- Monocytes can transform into macrophages when required
Describe dendritic cells (DCs)
- Type of WBC found on skin, on mucosa, and in blood
- Antigen-presenting cells (APCs): Process antigenic material and present it to other immune system cells
- Messenger between innate immunity and acquired immunity
Describe cytokines in the immune response
- Immunomodulating agents: Alter the immune response
- Direct and control systemic immune response
Explain what the immune system has memory; the inflammatory system does not means
- Some lymphocytes retain memory of an antigen after an initial encounter
- This means the immune response will be faster and stronger the next time an antigen enters the body
- The retained memory is called immunity
- The inflammatory system does not have this
Describe passive immunity
- Using antibodies created by another person to prevent infectious disease
- Natural: female to fetus
- Acquired: Injection for centrifuged donor antibodies
Describe active immunity
- Antibodies created by the person
- Natural: Microorganism causes the disease and antibody production\
- Acquired: Immunization, vaccination, booster (Killed-type vaccine or Live-attenuated vaccine)
Describe herd immunity
- Type of indirect protection from an infectious disease that occurs when a large percentage of the population becomes immune to infection
- Can be achieved through vaccination or through exposure to and recovery from infection
- Approximately 70% to 90% of a population needs immunity to achieve
What are the 2 major divisions of the immune response?
- Humoral immunity
- Cell-mediated immunity
Describe Humoral immunity
- Antibody-mediated immunity
- Production of antibodies
- Protection against bacteria and viruses
- B cells are the primary cells
Describe Cell-mediated immunity
- Cellular immunity
- T cells are the primary cells
- Regulates both major immune responses
Describe immunopathology
- The study of immune reactions involved in disease
- The study of diseases caused by the malfunctioning of the immune system
- E.g. Hypersensitivity, Autoimmune diseases, Immunodeficiency
List the 4 types of Hypersensitivity/Allergy
- Type I or anaphylactic type - Hay fever, Asthma, Anaphylaxis
- Type II or cytotoxic type - Autoimmune hemolytic anemia
- Type III or immune complex type - Autoimmune diseases
- Type IV or cell-mediated type - Granulomatous disease, Tuberculosis
Describe type 1 hypersensitivity - Immediate (anaphylactic type)
- The reaction occurs within minutes of exposure to an antigen
- Plasma cells produce IgE - IgE causes mast cells to release histamine, causing increased dilation and permeability of blood vessels and constricting smooth muscle in bronchioles of the lungs
- The reaction may range from hay fever to asthma and life-threatening anaphylaxis
Describe Anaphylaxis
- Occurs within minutes typically
- Widespread angioedema/urticaria which can restrict airway
- Administer epinephrine pen in emergent situations
Describe Type II Hypersensitivity (Cytotoxic type)
- Antibody combines with an antigen bound to the surface of tissue cells, usually a circulating red blood cell (RBC)
- Activated complement components and IgG and IgM antibodies in blood participate in this type of hypersensitivity reaction - This destroys the tissue that has the antigens on the surface of its cells (e.g., Rh incompatibility)
Describe Type III Hypersensitivity (Immune complex type (serum sickness))
- Immune complexes are formed between microorganisms and antibody in circulating blood - These complexes leave the blood and are deposited in body tissues, where they cause an acute inflammatory response
- Tissue destruction occurs after phagocytosis by neutrophils
Describe Type IV Hypersensitivity (Cell-mediated type (delayed))
- T cells that previously were introduced to an antigen cause damage to tissue cells or recruit other cells
- Responsible for the rejection of tissue grafts and transplanted organs