Immunity Flashcards
What are the two divisions of immunity?
nonspecific (innate)
specific (acquired after initial exposure)
What are some physical features and chemical features of innate immunity?
depends on the physical barriers such as: skin, GI, respiratory, epithelium
chemical factors like acid pH of stomach or vagina
vascular or phagocytic responses that result from injured or infected cells
How is the complement system involved in innate immunity?
to defend against infection by promoting phagocytosis and killing cells directly
it produces a series of activities (OILCAN)
What does opsonization do?
makes target cells more susceptible to phagocytosis
complement fragments (opsonins) bind to the surface of bacteria –> phagocytic cells with receptors for these fragments become attached to the opsonized bacteria –> increases the binding of bacteria for phagocytosis
What activates inflammation?
mast cells in anaphylaxis
What causes lysis?
due to the increased efficiency of bacterial phagocytosis
What is chemotaxis responsible for?
attract specific white blood cells to the area of damage
What does agglutination do?
changes the surface of the invading bacteria to make them sticky
Neutralization of the ______ sites on the surface of the antigen.
toxic
What does specific or acquired immunity do?
involves the production of antibodies against specific foreign antigens by lymphocytes
What do specific immune responses rely on?
lymphocytes
Specific/acquired immunity may be mediated by?
humoral (antibody) responses or cell-mediated (no antibodies)
In specific/acquired immunity some tissues will tolerate antigens without eliciting an inflammatory response. What are they?
brain, eye, testis, and the fetus
What are some products of immune cells within specific/acquired immunity?
tumor necrosis factor
immunoglobulins
cytokines
transforming growth factor
What does antibody mediated immunity depend on?
B lymphocytes
T lymphocytes
What are 4 features of B lymphocytes?
involved in the generation of humoral immunity
mature in bone marrow
aka plasma cells
make antibodies in the form of immunoglobulins
What are 3 features of T lymphocytes?
mature in thymus
involved in cell-mediated immunity
through the production of activated T-lymphocytes
There are T cell precursors in the bone marrow that go to the thymus where they differentiate into two types of T cells. What are they?
CD8 ad CD4 T cells
What do the CD8 T cells do?
become cytotoxic T cells which kill virus infected, neoplastic and donor graft cells
What do the CD4 T cells do?
differentiate into Helper T cells which develop into Th1 and Th2 cells
What do Th1 cells do?
activate macrophages
What do Th2 cells to do?
help B cells to make antibodies
Antibodies belong to a class of proteins called ____________ in the shape of a Y.
immunoglobulins
What is the more abundant immunoglobulin in circulation and what does it do?
IgG
promotes phagocytosis and cell lysis, confers passive immunity
What is the most abundantly produced immunoglobulin and where is it present?
IgA
saliva, tears, and breast milk
What does IgM promote?
aggulination, phagocytosis and cell lysis
Where is IgD found?
surface antibody on B lymphocytes
function unclear
What is IgE important for?
parasitic infections and come allergic responses
What determines the type of immunoglobulin?
the Fc (tail of the Y) region
What is responsible for antigen binding specificity?
Fab (arms of the Y)
Antibodies bind to __________, thus promoting their destruction.
antigens
Which immunoglobulin is secondary response and is most abundant?
IgG
Which immunoglobulin is primary response and is first in the fetus?
IgM
Which immunoglobulin is apart of compliment fixation and can cross the placenta?
IgG
What does cell- mediated immunity rely on?
activated T lymphocytes
What is cell-mediated immunity important for?
combating viral and fungal infections as well as against potential cancer cells
When are T cells activated?
by exposure to foreign antigens which are bound by specific surface receptors
Name the 3 types of T lymphocytes.
helper T lymphocytes
cytotoxic (killer) T lymphocytes
supressor T lymphocytes
Which T lymphocytes are most numerous?
helper T lymphocytes
Which T lymphocytes are activated by macrophage-processed antigens?
helper T lymphocytes
Once helper T lymphocytes are stimulated what is released?
lymphokines, interleukin 2-6 and interferon are released
What do cytotoxic (killer) T lymphocytes do?
lyse cells carrying the antigens to which they are sensitive; Lymphokine Activated Killer (LAK) cells are activated by lymphokines
What do suppressor T lymphocytes do?
inhibit lymphocytic function
Cell- mediated responses persist _______ than antibody responses.
longer
Natural active immunity.
immunity involves the production of antibodies after infection
Natural passive immunity.
occurs when the antibodies are produced in the mother and are transferred at birth to the infant
Artificial active immunity.
the antibody production is induced my immunizations
Artificial passive immunity.
antibodies are produced elsewhere (like in horses) and injected into or transferred to the patient
Natural active and artificial active immunity.
longer-lasting compared to natural passive and artificial passive immunity which is short lived
Hypersensitivity reactions- ACID.
Type I- Anaphylactic
Type II- Cytotoxic
Type III- Immune complex
Type IV- Delayed hypersensitivity
Explain Type I or Anaphylactic hypersensitivity rxn.
the antigen reacts with IgE causing mast cells to release histamine, heparin, as seen in allergies and asthma
Examples of Type II or Cytotoxic hypersensitivity rxn.
IgG, IgM destroys cells-erythroblastosis fetalis, acute transfusion reaction, autoimmune hemolytic anemia, ITP, Graves disease, Goodpasture syndrome and Myasthenia gravis
Explain Type III or Immune complex hypersensitivity rxn.
IgG mediated-immune complex triggers inflammation, as seen in serum sickness, SLE, RA, post-streptococcal glomerulonephritis and farmer’s lung
Examples of Type IV or Delayed hypersensitivity rxn.
T cell mediated as seen in Mantoux testing for TB, Touching poison ivy contact dermatitis, chronic Transplant rejection and Type 1 diabetes mellitus
NO ANTIBODIES PRODUCED
There are two classes of major histocompatability complexes. What are they?
Class I: antigens are found on all nucleated cells, recognized by CD8 (T killer) cells
Class II: found only on antigen-presenting cells like macrophages and dendritic cells, recognized by CD4 cells
