CP2 Chapter 19 & 20 Flashcards
Two major internal defense systems
Innate or nonspecific immune system
Adaptive or acquired immunity
Antigens
Any substances that are capable of generating a response from the immune system
Inflammatory response
Any substances that are capable of generating a response from the immune system
Physical and chemical barriers
Skin
Physical and biochemical components of the nasopharynx, gut, lungs, or GI tract
Population of commensal bacteria that compete with the invading pathogens
Classical signs of inflammation
Pain Heat Redness Swelling Loss of function
Neutrophils
Phagocytosis of antigens in tissue spaces
Monocytes
Follow neutrophils to inflammatory sites
Ingest and destroy antigens by phagocytosis
In blood called monocytes but when they migrate into tissue → macrophages
Macrophages
can be derived from tissue
Located in liver, brain, connective tissue, spleen, lung, bone marrow, and lymph nodes
Make up the mononuclear phagocytic system
Other important components of innate immune system
Natural killer cells (NK)
Small subset of lymphocytes in blood and lymph organs
Recognize and destroy host cells infected with microbes or viruses
Activate phagocytes by releasing interferon-γ
Interferons
Cytokines that elicit cellular reactions
Prevent viral replication
Complement system
Large group of proteins in blood
Complement cascade
Series of chemical reactions
Opsonization
binding of complement to the antigen
A mechanism of the adaptive immune system
Activated by C1 is bound to an antigen-antibody complex
Adaptive Immune System
More sophisticated
Divided into two components:
Humoral
Cell-mediated
Respond specifically to foreign substances
Antigens may be:
Bacterial, fungal, viral, altered host cells
Presence initiates humoral and cellular responses
Lymphocytes
Largely responsible for the adaptive immune system
Stem cells develop in yolk sac and then fetal liver and move to bone marrow near birth.
Destined to mature into either
B lymphocytes—mature in the bone marrow
Produces immunoglobulins
T lymphocytes—mature in the thymus
Maturation process
3 stages are - Lymphoblast, prolymphocyte, and lymphocyte
Mature cells leave bone marrow to enter spleen or lymph nodes, where they encounter antigens.
Each B cell develops a specific receptor molecule to a specific antigen.
Each time that antigen enters the body, the B cell reacts to it .
Passive Immunity
Maternal antibodies in colostrum
Receive preformed antibodies by injection
Antibodies produced in a donor animal
Short lived but immediate
Active Immunity or Immunization
Animals become resistant by either having the disease and developing antibodies or by immunization.
Elicits an antibody response by injecting microorganisms into an animal.
Attenuated
Weak but still alive
Lasts longer—more potent response
Inactivated
Killed
Safer
Adjuvant may be added to enhance the immune response.
Cell-mediated Immune System
T- lymphocytes
Similar to B lymphocyte maturation
Then develop receptors to specific antigens and become immunocompetent or antigen-committed T lymphocytes.
a.k.a. Naïve lymphocytes
T lymphocytes
Memory T cells
recognize antigens to which they d are able to lyhave previously been exposed.
Cytolytic T cells
recognize antigen particles that are on the surface of infected body cells anse and kill the infected cells.
Helper T cells
Recognize a phagocytized antigen as an antigen presenting cell (APC).
The APC displays a portion of the antigen on its surface to the helper T cell that releases cytokines to help phagocytize the microbe.
Immunologic Tolerance
Animals’ immune systems should not destroy their own cells.
In healthy animals mechanisms in place to prevent this
Ability to discriminate between self and not self is immunologic tolerance
Very complicated process
Handling Serologic Samples
Serum
Clot for 20 to 30 minutes at room temperature
Centrifuge for 10 minutes at ≤1500 rpm
Plasma
Centrifuge immediately after collection
Pipette serum or plasma into a transfer tube and label
Freeze or refrigerate for later use
Tests for Humoral Immunity
Enzyme-linked immunosorbent assay (ELISA)
Competitive enzyme-linked immunosorbent assay (CELISA)
Lateral flow immunoassay
Latex agglutination
Lateral Flow Immunoassay
a.k.a. Rapid immunomigration or immunochromatography
Uses colloidal gold, enzymes, and color reagents or agglutinated latex particles
Antibodies present in the membrane of the test cassette where sample is applied.
Positive results show two areas of color, test, and control.
Chemiluminescence
Principle similar to the ELISA method except that the test uses a substrate that reacts to produce light.
Amount of light produced can be quantified.
Used for detection and quantification of pathogens as well as other substances
Thyroid hormones, cortisol, pancreatic lipase, progesterone, and testosterone
