The Immune System & Vaccination Basics

1. The Immune System & Vaccination Basics By Jeannie Stall, R.V.T. Credits: Clip Art Alleice Summers AVMA AAHA Bassert/McCurnin

2. The Immune System • Immune System = System of defense - Without it, animals couldn’t survive Immunity = The actions of the functioning Immune System

3. Immunity • Defense system that guards/defends against disease-causing agents, either foreign or internal • Active 24 hours / 7 days a week • Two main categories: Non-Specific and Specific

4. Non-Specific Immunity Also known as “ Innate” or “ Inherited” Shows same response to any/all antigenic insults. • Species Resistance • Mechanical/Chemical barriers • Reacts by producing an Inflammatory Response • Interferon • Complement

5. Species Resistance • Genetic ability of a particular species to provide a defense against certain pathogens. Dogs aren’t susceptible to Feline Leukemia Virus Cats don’t acquire Canine Distemper Virus Cats can’t get the protozoan, “Ich”, from goldfish goldfish

6. Mechanical & Chemical Barriers • SKIN & MUCOUS MEMBRANES Skin: “ The 1st line of defense”- A great mechanical barrier against microorganisms, as long as it is intact. Produces Sebum/Mucus/Enzymes as chemical barriers to inhibit or destroy pathogens.

7. Inflammatory Response • “The 2nd line of defense”. Invaded cells release enzymes known as “mediators”. Mediators job: Attract WBC’s to area (phagocytosis), dilate blood vessels, while vessel permeability. Signs of inflammation: Heat, redness, swelling & pain d/t these chemicals The > blood flow temperature, which inhibits the invading organism’s growth.

8. WBC’s Phagocytosis =WhenWBC’s “gobble up” invading microorganisms & kill these pathogens via chemicals found in the cell’s cytoplasm. Monocytes are WBC’s in the blood stream, but when they enter the tissues, they are called Macrophages. Theyare components of both the Non-Specific & the Specific Immune System.

9. Interferon & Complement • Invaded body cells produce these 2 chemicals Interferon: This chemical substance “interferes“ with invading viruses’ ability to replicate/reproduce in host’s cells. Complement: This enzyme binds to invader’s cell wall, puncturing small holes in it, causing it to rupture, which is known as lysis.

10. Specific Immunity • “ The 3rd line of defense”. • Performed by two types of Lymphocytes ( WBC’s ): 1. B- cells : Produce antibodies to response to a specific antigen stimulation ( Humoral Response ) 2. T- cells : Bind directly w/ pathogen’s cell to destroy or render it harmless ( Cell Mediated Response )

11. B- cells • Slower response to pathogen. Originate in bone marrow. Contact specific antigen/pathogen & clone identical B- cells, specific to that particular antigen. Can be either: 1. “Plasma Cells” - produce lg. protein molecules a.k.a. Antibodies/ Immunoglobulin, that “lock onto” pathogen. Takes time- 7 – 10 days 2. “Memory Cells” - Ability to recognize the same invading antigen/pathogen, if/when, it ever crosses paths with it again.

12. T-cells • Created in the bone marrow • Exit bone marrow via circulation and arrive @ thymus. ( Lymph system gland located in the mediastinum) T-cells get “educated” in thymus to recognize their own animal’s cells. After “graduation”, leave to circulate thoughout the body, lymph nodes & spleen, in search of pathogens. Macrophages latch on to invaders & transport them to T-cells.

13. T-cells con’t……. • Macrophages “latch onto” invading pathogens/antigens & transport them to T-cells. T-cell “locks onto” receptor spot on pathogen’s surface & replicates. All these new T-cells go to invader’s location & eliminate them. This response is quick & effective.

14. B –cells & T – cells con’t……. • Further Immunity classifications : 1. “Inherited” – Immunity due to genetic factors influencing fetus before birth. 2. “Acquired” - Resistance/ Immunity that develops after being born. a. Natural: Ongoing exposure to pathogens b. Artificial: Deliberate innoculation/vaccination

15. Further Classifications • Natural & Artificial have further subdivisions: Passive Immunity- Antibodies formed in one infected animal are transferred to a non-infected animal. Active Immunity- Animal’s own immune system crosses paths with a pathogen then mounts an immune response.

16. Infectious Dz. Transmission Routes • Horizontal: Infected( non-parent) animal’s pathogens spread to healthy one 1. Direct : Licking & biting / Sexual contact / Airborne ie: FIV / Brucellosis / Bordatella 2. Indirect via : Vector = Transports pathogen a. Biological – Carries & supports pathogen’s replication Mosquito = Heartworm b. Mechanical - Carries pathogen only Flies = Pinkeye Fomite = Inanimate objects a. Feeding bowls = Panleukopenia Iatrogenic = Vet. Uses contaminated equipment, needles, boots…. Vertical : Pathogen spread via parent, usually Mom, to offspring via reproduction

17. Vaccine Regulation • In U.S. -- Center for Veterinary Biologicals Division of United States Department of Agriculture ( U.S.D.A. ) Acceptable level of protection (vaccine efficacy) is just 65 % to 95 %

18. Vaccines • Vaccines do not give Immunity!!!! Vaccine’s purpose is to stimulate immune response, BUT it’s up to animal’s immune system to build an adequate immune response. • Stressed or compromised immune systems can’t respond sufficiently to the stimulation of the vaccine, resulting in non-protected animals. • Hence, all animals require a physical evaluation prior to vx. to determine a current health status.

19. Vaccine protocol • Shipped on ice from manufacturer Unpack shipment immediately upon arrival If not cold when received, RETURN IT !!! Refrigerate vaccine upon arrival • Mix as directed : Sterile diluent placed into “cake” vial Gently invert to mix---- Don’t create foam shaking it Once mixed , it MUST be given in a timely manner Shouldn’t stay in syringe > 15 min. d/t plastic issues Keep vx. cool until administered

20. Immuno-compromising Issues • Infections: WBC’s @ max. working level & unable to muster new response to vx. • Poor nutritional status : Thin/Obese ie: Body Conditioning Score Unhealthly situation prevents immune system rally. • Age: Pediatrics /Geriatrics compromised d/t “undeveloped” or “depleted” systems. • Compromised due to Dz.: FIV , Fe Leuk, Chemotherapy ….. • Administer “half- dose vx.“ to sm./young animals: Wrong! Wrong! St. Bernard or Yorkie, it requires a certain vx. volume to stimulate immune response !

21. Vaccination Classifications • Core : Required • Non-core (Optional ) : Administered based on animal’s geographic location, lifestyle exposure & benefit /risk ratio • Not recommended : Available on the market, but not advised due to poor vaccine efficacy or low benefit/risk ratio

22. Core vaccinations Those vaccinations appropriate to provide protection in most animals against diseases that pose a risk of severe disease because the pathogens are virulent, highly infectious and widely distributed in the region. They are: - Highly efficacious - Maintain “benefit vs. risk” ratios high enough to warrant their general use - Be of substantial public health importance - Are required by law

23. “ Core “ Vaccines CANINEFELINE Rabies Rabies Distemper Panleukopenia Parvovirus Viral Rhinotracheitis Hepatitis (Adeno2) Calicivirus Non-Core Vx. Appropriate Due to Lifestyle: Bordatella Leukemia Lyme Corona Lepto Among Other Vaccinations………

24. Vx. Abreviations Canine: • DHLPPC = Distemper / Hepatitis / Leptospirosis / Parainfluenza/ Parvovirus/ Corona • DA2PP = Distemper /Adeno 2 Virus /Parainfluenza /Parvo Feline: • FVRCPC = Feline Viral Rhinotracheitis / Calici / Panleukopenia / Chlamydia • FeLeuk = Feline Leukemia • FIV= Feline Immunodeficiency Virus Both Species: • RV = Rabies

25. Terminology • Modified Live Virus (MLV)( Attenuated): Live disease-causing organism component altered to render it safe/safer. May revert to virulent form. Not for use in immuno-compromised animals. • Killed: Component of vaccine no longer alive • Intranasal: Vaccine administered via nasal drops • Recombinant: Created, single, purified protein of organism (DNA separated & spliced) No chance of causing dz. • Adjuvant: Irritating vx. additive designed to stimulate immune response. Rxns/Fibrosarcoma!

26. Adverse Effects • Reactions: Mild : Most common - Hives, pruritis (itching), redness, swelling (facial, airway, generalized) Usually occur 30 min. - 4 hrs. post vx. dose, but can be up to 12 – 24 hours post Severe - Anaphylactic- IMMEDIATE & LIFE THREATENING !!! Vx. Induced Lymphosarcoma- Felines Genetic factor???