Antibody Production and Vaccination Topic 11.1 Antibody Production and Vaccination

Understanding: Every organism has unique molecules on the surface of their cells ANTIGEN = any foreign molecule that can trigger an immune response Most common = proteins & large polysaccharides Found on surface of cells (cancer, parasites, bacteria, pollen, viruses) Human cells also have proteins & polysacs on surface (MHC proteins) A healthy immune system can distinguish b/n “self” and “non-self” ALLERGY = hypersensitivity of immune system HAY FEVER = allergy caused by pollen or dust

Influenza virus cell-surface antigens

Application: Antigens on the surface of RBC’s stimulate antibody production in person w/a different blood group. ABO blood groups: types A, B, AB & O Rh blood groups: Rh+ and Rh- Mismatches of blood types cause: “agglutination” (clumping) “hemolysis” (RBC’s destroyed) “coagulation” (clottin; from liquid to gel)

A = when mixing Type A with Type A blood = GOOD A = when mixing Type A with Type A blood = GOOD! B = when mixing Type B with Type A blood = BAD!

Review: types of white blood cells

Understanding: B lymphocytes are activated by T lymphocytes in mammals

Challenge and response The “challenge” = antigens on surface of pathogens The “response” = what your immune system does: Macrophage ingests pathogen mac displays antigens to helper T cell Helper T cell binds to antigen and activated Activated helper T cell binds to B cell & activates it with proteins B cell divides to produce plasma cells, which secrete specific antibodies B cell also divides to produce memory cells, for later

Antibody production

Understanding: Plasma cells secrete antibodies. Plasma cells = mature B cells that produce & secrete antibodies during immune response Antibodies = proteins made in response to antigens Large amount of rER for making and transporting antibodies Each plasma cell contains the entire DNA of the human individual, but only expresses ONE gene for the ONE protein it makes

Understanding: Activated B cells multiply to form a clone of plasma cells & memory cells Clone = plasma cells that all produce same type of antibody “Clonal selection” = generation of large numbers of plasma cells that produce ONE specific antibody type Antibodies stay in body for few weeks or months Plasma cells persist until infection overcome Memory cells persist long after infection and inactive If exposed to same pathogen, memory cell becomes active and responds very rapidly Immunity = individual has antibodies or memory cells

Clonal Selection = generation of large numbers of plasma cells that produce ONE specific antibody type

Understanding: Antibodies aid the destruction of pathogens HOW do antibodies work? Opsonization: coating antigen with antibody to enhance phagocytosis Neutralization of viruses & bacteria: prevents adhesion of bac & docking of virus Neutralization of toxins: bind to toxins, preventing them from affecting cells Activation of complement proteins: form a pore in pathogen membrane, water and ions enter, pathogen cell lyses Agglutination: sticking together of pathogens so they can’t enter cells and easier for phagocytes to ingest a bunch at a time

How antibodies work!

Understanding: Immunity depends upon the persistence of memory cells.

Understanding: Vaccines contain antigens that trigger immunity but don’t cause disease May contain live attenuated (weakened) pathogen or just its antigens Stimulates primary immune response If ever exposed to real pathogen, secondary immune response kicks in! Example: TB (tuberculosis) vaccine Live attenuated Mycobacterium bovis, a relative of Mycobacterium tuberculosis Immune system makes antibodies that act on both species, without causing disease Tuberculosis video https://www.youtube.com/watch?v=IGZLkRN76Dc

Nature of Science: Consider ethical implications of research: Jenner tested his vaccine for smallpox on a child. Edward Jenner, 18th century scientist – first person to use human being (8 yr old boy) as research subjects in testing a vaccine (smallpox) Nuremberg Code after WWII protects research subjects WHO’s International Ethical Guidelines for Biomedical Research Involving Human Subjects (1993)

Smallpox

Application: Smallpox was the first infectious disease of humans to have been eradicated by vaccination https://www.youtube.com/watch?v=yqUFy-t4MlQ

Vaccine scars

From BCG (Tb) or Smallpox vaccine

Eradication of smallpox 1950 Pan American Health Organization launched effort 1959 World Health Assembly pass resolution for global effort 1967 Smallpox Eradication Unit created 1977 last known case of smallpox (in Somalia) Reasons for success: Only transmitted by humans (unlike yellow fever) Symptoms show up quickly (unlike polio) Immunity is long-lasting (unlike malaria)

Skill: Analysis of epidemiological data related to vaccination programmes. Epidemiology = study of distribution, patterns & causes of disease in population Plan & evaluate vaccination programs 1988 WHO, UNICEF & Rotary Foundation combined efforts to eradicate polio UNICEF launched effort to prevent tetanus through vaccination Epidemiologists use info about geographic distribution to determine origins of outbreaks & determine effectiveness of vaccination programs 2012 India declared polio-free (until person with polio comes in) DBQ p 473 #1-6

Understanding: Pathogens can be species-specific although others can cross species barriers Human-specific pathogens: syphilis, polio, measles, HIV Dog-specific pathogens: canine distemper virus Cat-specific pathogens: feline immunodeficiency virus (FIV) Reasons some pathogens affect some species and not others: Body temp may not reach temp needed to support pathogen Species may lack receptor on cell for pathogen toxin Zoonosis = pathogen that can cross species barrier Examples of zoonotic diseases: bubonic plague, Rocky Mountain spotted fever, Lyme disease, bird flu, West Nile virus Reasons we see increasing zoonotic diseases: increased contact between animals & humans through livestock & disruption of animal habitats E.g. 1990’s Malaysia, pig farming in habitat of bats infected with Nipah virus: virus moved from bat to pig to man!

Thermal scanning camera in airports for possible carriers of bird or swine flu

Understanding: White cells release histamine in response to allergens Mast cells = in connective tissue; secrete histamine in inflammatory response & allergic rxn Basophils = in blood; wbc’s that release histamine Histamine = dilates blood vessels and causes them to leak Histamine released in inflammatory response

Understanding: Histamines cause allergic symptoms

Allergic reactions Itching Fluid build-up Sneezing Mucus secretion Inflammation Rashes Anaphylaxis = dangerous whole-body allergic rxn (swelling, hives, low BP, dilated blood vessels; usually given epinephrine)

Understanding: Fusion of a tumour cell with an antibody-producing plasma cell creates a hybridoma cell

Understanding: Monoclonal antibodies are produced by hybridoma cells Monoclonal antibodies (mAb) = monospecific antibodies made from clones of one single parent cell For treatment & diagnosis of diseases E.g. test for malaria, test for HIV, troponin blood test for heart attacks, creation of antibodies for treatment of rabies, pregnancy tests

Application: mAb’s to hCG are used in pregnancy test kits hCG = human chorionic gonadotropin = hormone produced by embryo If pregnant, urine will contain hCG

NOVA’s “Vaccinations: Calling the Shots” http://www.pbs.org/wgbh/nova/body/vaccines-calling-shots.html