Transcript The Immune system - Locust Trace Veterinary Assistant Program

THE IMMUNE
SYSTEM
UNIT 7 IMMUNITY AND VACCINES
VETERINARY ASSISTING PROGRAM
RESPONSIBILITIES
• The immune system is responsible for protecting the
animal from potentially harmful organisms attempting to
invade.
• It is a VERY complicated system
• It must be able to recognize substances that are foreign to
the body by recognizing what is naturally occuring
ANTIGENS
• Antigens are large, complex molecules that are foreign to
the body.
• Once they enter the body, the stimulate an immune
response for which antibodies are made.
• Antibodies: specific protein produced to protect against a
disease. Attacks the pathogen.
• Pathogen: microorganism that causes disease
LYMPHATIC TISSUE
• The body has
lymphatic tissue
distributed throughout
to detect antigens
quickly.
• Within the lymphatic
system are lymph
nodes, which is lymph
tissue encased in
connective tissue.
• These lymph nodes
can be palpated on
almost any dog.
•
Location of Lymph Nodes in the Dog. Digital image.
Immune System Tumors in Dogs. Merck Manuals, July
2011. Web. 22 Aug. 2014.
SPLEEN
• Large reddish-brown organ within the
abdomen that is involved in the
immune system and filtering blood.
• Contains areas where immune cells
scan incoming blood for antigens.
• Houses the cells responsible for
producing antibodies.
• Important but not necessary
•
Digital image. Lymphatic System Anatomy
and Function. PetEducation, n.d. Web. 22
Aug. 2014.
•
•
Lymph nodes also house the cells
responsible for antibodies and other
organs also help filter the blood
If damaged, extensive bleeding can
occur
Common site for tumors
BONE MARROW
• Essential for the immune system
• Produces WBC’s
• Complicated process
• When the body recognizes an antigen, neutrophils and
macrophages phagocytize the antigen
• It is then broken down within the cell
• A substance is release to begin immune response.
• This release kills the virus or slows replication, attracts
other immune cells to the area, and kills the already
damaged cells.
• This substance also affects the hypothalamus
LYMPHOCYTES AND
ANTIBODIES
Specific lymphocytes come in contact with specific antigens
•
Stimulates repeated mitosis
• Results in a large number of lymphocytes
• Designed to react to this particular antigen, this is called clonal
expansion.
B lymphocyte or B cell
B cells
plasma cells
secrete antibodies=humoral
immunity
• Antibody is Y shaped, arms of the Y detect the antigen
• Pathogens have many antigenic determinate sites on its surface to
which antibodies bind
• Antigen-antibody complex stimulates phagoctyic cells so pathogens are
phagocytized (destroyed)
• T-Cells- type of lymphocyte associate with cell-mediated immunity
Antibodies are produced primarily in the
lymph nodes but also in the spleen and bone marrow.
HYPOTHALAMUS
• Any time the hypothalamus if affected, it elevates the body
temperature.
FEVER!
• Fever is designed to aid in the fighting of the pathogen
• A high body temperature hinders the replication of an
infectious organism or can even kill it.
• It also stimulates the activity of lymphocytes, phagocytes,
and antibodies.
INFLAMMATION
• Can be a result of physical injuries or reaction to invasion
of a pathogen
• This response delivers more WBC’s and antibodies to the
infected area
• 4 signs of inflammation
• Pain
• Heat
• Redness
• Swelling
• The swelling is referred to as edema. This is a build up of
fluid under the skin due to increased capillary
permeability.
INFECTION
• Not antibody related,
cell mediated
response only
• This is when a large
number of cells invade
a specific site
• A combination of
WBC’s, invading
pathogens, dying and
destroyed tissue
creates pus
•
When describing pus,
the term is purulent!!
• Pus trapped in a
pocket is referred to
as an abscess
Digital image. Abscess on Dog's Shoulder.
BerryHaven Veterinary Group, n.d. Web. 22
Aug. 2014.
VACCINES
IMMUNITY CONTINUED…
CREATING IMMUNITY
• Immunity can occur one of two ways:
• Active immunity
• Passive immunity
ACTIVE IMMUNITY
• Active immunity results from exposure to a pathogen,
either through a vaccine or natural infection
• Any exposure thereafter will trigger the immune system’s
memory and quickly destroy the pathogen
• This can last for different periods of time, ranging from 6
months to years
Dog Receiving Vaccine. Digital
image. Bordetella and Pets. VPI
Veterinary Pet Insurance, n.d.
Web. 22 Aug. 2014.
PASSIVE IMMUNITY
• Immunity resulting from the transfer of antibodies from
one animal to another
• Mother to offspring through colostrum
• Commercial diets (Esbilac)
• Plasma donation
• This immunity is temporary and usually only lasts several
weeks to months
TYPES OF VACCINES
1. Modified live vaccines
• Uses altered antigens created from a pathogen and places
a small amount of the disease into the animal’s body
• Pathogen is weakened, so it can divide but not cause
clinical disease
• Boosters can be given but not always needed
2. Killed vaccines
•
•
•
•
Uses killed pathogens
Can no longer divide but still has antigens to trigger an
immune response
Must get a booster
Slower
MLV
Vaccine box. Digital image. Nobivac Canine 1DAPPv (Galaxy DA2PPv). Valley Vet Supplies,
n.d. Web. 22 Aug. 2014.
KILLED
Rabies Vaccine Vial. Digital image. Nobivac 3
Rabies - 10 Dose Vial. KV Supply, n.d. Web.
22 Aug. 2014.
VACCINE ROUTES
• Most vaccines come in an injectable form
• Subcutaneous
• Intramuscular
• Others are intranasal (Bordetella)
Intranasal Vaccine. Digital image. Kennel Cough. MarvistaVet, 11 Dec. 2012. Web. 22 Aug. 2014.
ALLERGIC REACTIONS
• Not all immune responses are to prevent disease. Some
occur against antigens that are not harmful
• Allergens are substances that create an allergic response,
such as pollens, dust mites, and flea saliva
• An animal’s sensitivity to this causes a release of
histamine. This release causes itchiness, eye and nasal
discharge, sneezing, rubbing at eyes, and redness of the
skin.
• Drugs given to help treat this are antihistamines
• Atopy is an allergic condition of the skin involving pruritus
and alopecia
SEVERE ALLERGIC
REACTIONS
• An allergic reactions that is generalized and life
threatening is called anaphylaxis.
• Causes bronchoconstriction and leaky vessels which lead
to respiratory distress and shock
• Epinephrine counteracts physiologic effects of histamine.
• Must be given quickly!
TITER
• These tests measure the level of antibodies in the
bloodstream against a specific disease
• Results are reported as a ratio
• A titer of 1:256 has more antibodies than 1:64
• A high titer proves that an animal has been exposed to a
pathogen
• Not when the exposure occurred, could be from a vaccine
REVIEW
• Lymphatic is a highly complex system with lymph nodes
throughout the entire body
• Many organs are involved with the immune system
• Infection is not antibody related
• Vaccines can be killed or modified live
• The types of immunity are passive and active
• Allergens can cause a life threatening event known as
anaphylaxis