VETERINARY IMMUNOLOGY
Oct 26, 2014
VETERINARY IMMUNOLOGY
IMMUNOLOGY• the scientific study of all aspects of immunityIMMUNITY • non- susceptibility to the invasive or
pathogenic effects of microorganisms• Is an enhanced state of responsiveness to a
specific substance, induced by prior contact with that substance
• State of resistance to an infection
Historical Highlights in Veterinary Immunology
Date Event
12th century “Variolation” or “Inoculation” -Chinese rubbed infected pox materials on cuts of skin
1754 Rinderpest or “cattle plague” outbreak started inoculation of healthy animals with piece of string soaked in the nasal discharge of infected animal as preventive measure to control rinderpest
1798 Edward Jenner used cowpox to vaccinate humans against small pox. Vaccination term was coined from “vacca” latin for cow
1879 Louis Pasteur established the general principle of vaccination using Pasteurella multocida model in chickens.
1879 Louis Pasteur•Founder of the Science of Immunology•Father of Immunology•First to produce Bacillus antracis vaccine•Developed the first Rabies vaccine using dry spinal cord of rabies infected rabbits
1890-1904 Daniel Salmon and Theobald Smith used heat killed culture of Salmonella enterica cholerasuis to protect pigeonsVon Behring and Shibasaburo Kitasato sucessfully tested vaccines for diptheria and tetanusVon Behring named and discovered antibodies
1905 Robert Koch discovered the tuberculin reaction and won the Nobel Prize
1955- 1960 Jonas Salk and Alfred Sabin discovered the different forms of the poliomyelitis vaccine which was used to control the disease worldwide.
1984 George Kohler and Cesar Milstein won Nobel Prize for production of monoclonal antibodies
• Defense of the body or protection of the body is a function of multiple defense systems that can control or destroy most of invaders
• An effective immune system is essential to life
TYPES OF IMMUNITY
NATURAL OR INNATE IMMUNITY• Nonspecific• Present from birth• Consists of
a. Barriers to antigens: e.g. skin, mucous membranes, b. chemical and cellular defense mechanisms , e.g.
Inflammation- a focused defense response where local changes in tissues brought about by microbial invasion or tissue damage result in increased blood flow and local accumulation of cells that can attack and destroy the invaders.Complement System
TYPES OF IMMUNITY
ACQUIRED IMMUNITY (Specific/ Adaptive)– Expressed after exposure to a given substance or
antigen and is specific– An adaptive response wherein the system can learn to
recognize invaders when it encounters them again and that can respond even more rapidly and effectively. The acquired immune system can recognize foreign invaders, destroy them and retain the memory of the encounter.
– Consist of: Humoral Immunity Cell Mediated Immunity
A comparison of Innate and Acquired Immunity
INNATE IMMUNITYAlways “on “
ACQUIRED IMMUNITYTurned on by antigens
Cells involved
Onset
Specificity
Potency
Memory
Effectiveness
Macrophages, dendritic cells, neutrophils
Rapid ( min- hrs)
Common microbial structures
Maybe overwhelmed
None
Does not improve
T and B cells
Slow (days –weeks)
Unique antigens
Rarely overwhelmed
Significant memory
Improves with exposure
THE BODY’S DEFENSES Invading Microorganisms
Physical Barriers Examples:
Innate Immunity Examples:
Specific Immunity Examples:
BODY DEFENSE
Acquired Immunity
Humoral Immunity
Antibodies
Cell mediated Immunity
Lymphocytes
Innate Immunity
TYPES OF IMMUNE RESPONSE
A. Humoral Immune Response (Antibody mediated Immunity)- acquired immunity response to exogenous antigens that are extracellular
Antibodies or Immunoglobulins- protective factors synthesized by the body against an antigen or upon exposure to an antigen.
Ex. Tetanus antitoxin when injected to a horse prevents tetanus infection.
HUMORAL IMMUNE RESPONSE
A. Primary Immune Response- response that occurs following a first exposure to an antigen, antibodies produced are relatively small, no antibodies are detected for a week ( lag period) after injection. Antibodies peak at 10-14 days before declining.
B. Secondary Immune Response- a response that occurs following a second or subsequent exposure to antigen, the response is immediate and antibody rises rapidly at a higher level than the primary response. The features of the secondary immune response indicate that the immune system is able to remember previous exposure to an antigen also known as ANAMNESTIC RESPONSE.
TYPES OF IMMUNE RESPONSE
B. Cell Mediated Immune Response (CMI)– Mediated by lymphocytes and phagocytes E.g. Graft rejection demonstrates the existence of
a mechanism wherein foreign cells differing slightly from an animals own normal cells are rapidly recognized and eliminated.
– CMI and Humoral Immune Response not entirely separate but they act together.
TOLERANCE
• The immune system must recognize its own cells as not foreign and not mount an immune response. Tolerance breakdown results to autoimmune disease.
• Examples. Systemic Lupus Erythromatosus (SLE), Hemolytic anemia and myasthenia gravis
MECHANISM OF IMMUNE RESPONSE
1. Method of trapping and processing antigens (Ag)
2. Mechanism of reacting specifically to an Ag3. Produce antibodies (Ab) or participate in CMI4. Cells retain memory of event and able to
react to the same Ag in the future.
Mechanism of Acquired Immune ResponseForeign Material
Extracellular Intracellular(Exogenous) (Endogenous)e.g. parasite, protozoa, bacteria, fungi e.g. viruses, intracellular protozoa , cancer
cells
Antigen Processing Cells ( APC)
Antigen sensitive CellsB cell T cell
Memory cells Ab producing cells Effector cell Memory cell
Ab production Cell mediated Immunity
Antigen elimination
Stop