Lecture 3 Flashcards
An antigen is?
a part of an organism or substance that is recognized by the immune system as non-self
-often cell-surface protein or sugar
Passive immunity
- preformed antibody acquired from an outside source
- half-life of ~21 days
Non-specific Immunity (Anatomical Defences)
- Skin/Hoof/Hair, mucous membranes
- mucus
- Cilia
- Lacrimal secretions
Non-specific immunity(Humoral defences)
- play a role in inflammation
- complement system
- cytokines
- lysozyme
Lysozymes function? found in?
Found in tears
-breaks down the cell wall of bacteria
Cytokines are?
communication molecules
The three roles of the complement system include?
complement fixation
opsonisation
trigger inflammatory reaction
Complement fixation
binding to and destroying foreign cell membranes
Opsonisation
tagging of foreign cells for stimulation of phagocytosis
Non-specific Immunity(cellular defences)
phagocytes
- lack memory
- contribute to inflammatory response
Neutrophils
- WBC
- PMNSs
- ingest and digest foreign particles by lysozyme digestion
- very non-specific
Neutrophils attracted to sites of infection and inflammation by?
chemotaxis
-chemical signaling from cytokines and interleukins
Neutrophil activation
become sticky, marginate in circulation, squeeze through endothelial junctions(diapedesis) and migrate to the site of infection or tissue damage
Neutrophils are specifically important in?
mammary glands and uterus
Monocytes
largest WBC
5-8%
cytoplasm contains lysosomes
eventually leave circulation to become macrophages in tissue
Function of monocytes
non-specific removal of bacteria, fungi, necrotic debris and act as antigen presenting cells to T lymphocytes
Humoral wing of the immune system
B cells
production of specific antibodies
Cell mediated specific immune system
- macrophages
- tcells
- cytokines
B lymphocytes mature in the?
bone marrow
T lymphocytes mature in the?
mature in thymus
Antibody production by B lymphocytes
- B cell divides repeatedly
- forms a clone of antibody secreting plasma cells
- after assault is over some become memory B cells
Types of immunoglobulins(antibodies)
- proteins produced by B cells(plasma cells)
- antigent-antibody complexes stimulate additional production of antibody
- IgG, IgA, IgM, IgE
IgA
found on mucosal surfaces
-GI, respiratory, reproductive tracts
10-15% of total
IgM
circulates mainly in blood, not tissue
generally produced most quickly in response to antigenic stimulation
-first to scene first to leave
5-10%
IgG
most common(80%)
found equally in circulation and in tissue
has the longest half-life of all the antibody types
gives us titres
IgE
associated with parasites and allergies
Function of antibodies
released into the intercellular fluid where they bind to the infecting antigen and flag it for destruction by phagocytes and complement system
coating may prevent attachement or invasion of bacteria or virus
blind toxins secreted by pathogens
What is needed to protect phagocytes from oxidative damage from radicals generated in digestion?
- vitamins E and A
- Selenium
- copper
Immunize
to stimulate/confer a protective immune response
Modified live vaccine
lab-attenuated virus
produce a low-level true infection
replicates in host
activates both humoral and cell mediated adaptive immunity
killed virus vaccines
completely inactivated
all that’s residing in the outside surface of the virus
no replication
adjuvants added to increase immune response
only targets humoral adaptive immune system
Advantages of Killed Virus
generally stimulate good humoral response
can be used in all stages of lactation
no risk of shedding
no risk of reversion to virulence
properly stored a partial bottle can be used
Disadvantages to Killed virus vaccines
primer dose needs to be boostered in 2-4 weeks
ability to stimulate CMI?
antibodies alone are not protective for many diseases
antibodies produced against strains in the vaccine
more expensive
high levels of antibody for approx 4-6 months
Advantages of modified live vaccines
stimulate cell mediated and humoral wings of the immune system single dose usually provides protection less expensive per dose more rapid immune response longer lasting protection
Disadvantages to Modified live vaccine
historically cannot be given to pregnant animals
can be inactivated by heat, sunlight, chemical residues in syringe
must be used within hours
Onset of immunity is typically?
2-4 weeks after vaccination
Compliance for vaccination success?
storage and transportation
mixing, usage, maintenance of sterility
correct route of administration
accurate records to vaccinate all animals at correct times
testing and vaccination of purchased animals
