(LE3) Practical Immunology Flashcards
What are your two types of immunity?
Acquired
Innate (genetic factors)
- mutations or selective advantage
What are the two types of acquired immunity?
Active (own antibodies)
- memory (long-lived)
Passive (ready-made antibodies)
- temporary
- no memory component
What are two types of active immunity?
Natural - exposure to infectious agent
Artificial - immunization
What are two types of passive immunity?
Natural (maternal antibodies)
- e.g. placenta and breast milk
Artificial (antibodies from other sources)
- e.g. horse serum for rattlesnake bites
What is a vaccine?
suspension of microbes or microbial Ag that induce immunity in host without causing disease
What are the types of whole-cell vaccines?
Inactivated (killed)
Attenuated (alive, weakened)
What are the types of acellular vaccines?
Toxoid (inactivated toxin)
Recombinant Subunit (genetically engineered)
Conjugated (Polysaccharide Ag + Toxoid)
- Weak antigen (weak memory), so combined with Toxoid
- e.g. TdaP
What are examples of a live attenuated vaccine?
Oral Polio vaccine
Measles
Smallpox
What are examples of an inactivated vaccine?
Inactivated Polio Vaccine (IPV)
What are examples of subunit (purified antigen) vaccines?
Haemophilus influenzae type B (Hib)
Hepatitis B
What are examples of toxoid vaccines?
Tetanus toxoid
Diphtheria toxoid
How do the effectiveness and safety of inactivated vaccines compare to attenuated ones?
Inactivated: may damage the Ag and have poor efficacy
Attenuated: have the possibility of conversion back to virulent form (reversion)
How do the two forms of Polio vaccines compare?
IPV (injectable)
- Dr. Salk
- really safe
- 60-70% effective
OPV (oral)
- Dr. Sabin
- Really safe
- > 90% effective
- Reversion. 1/500k children
Both combined to increase safety and efficacy. IPV first, then OPV
What other factors are considered when creating vaccines?
- cost
- shelf life
- strains of pathogen covered (e.g. flu, HPV and covid)
What must be true for a disease to be a candidate for eradication?
Diseases with human-only reservoirs: Polio, Measles, Mumps, Rubella, Smallpox (1980)
What is serology?
Use of a patient’s blood for diagnostic tests (plasma minus clotting factors)
- might detect Ab in serum
- might detect Ag in serum
What are the limitations of serology?
- Ab not produced right away (false negative)
- can’t distinguish between current and past infection or vaccination
- intracellular Ag won’t be detected
How do agglutination reaction diagnostic tests work?
- use cells and particles covered in specific Ag
- add patient’s serum which may or may not have Ab to those Ag
Ab present in serum = agglutination (pos)
Ab not present in serum = no agglutination (neg)
Based on this test, what is this patient’s blood type? What antibodies do they have? Who can they receive blood from?
AB-positive
no antibodies
Universal acceptor
Based on this test, what is this patient’s blood type? What surface antigens do they have? Who can they receive blood from?
O positive
Rh antigen
Accept O positive and O negative
What is RPR test used for? How does it work?
Syphilis
- type of agglutination test
- screening test
- looks for reagin (non-specific Ab) antibody in blood
- charcoal beads bind with reagin Ag
How does precipitin test work?
-serum added to bottom of tube
- add solution of antigen
- if Ab present, there will be visible clumping and appear clooudy
How do Fluorescent Ab tests work?
Use fluorescently-tagged antibodies to bind to specific molecules in sample
How do direct and indirect FA testing differ?
Direct FA - detects Ag in sample
Indirect FA - detects Ab in sample
What is ELISA testing?
Enzyme Linked Immunosorbant Assay
- used to detect and measure Ab or Ag in patient serum
What does direct ELISA look for?
Detects antigen in patient’s serum
- enzyme-linked Ab binds patient’s Ag
- e.g. HCG in pregnancy test
What does indirect ELISA look for?
Detects Ab in patient’s serum
- enzyme-linked Ab binds patient’s Ab
- e.g. HIV test
What are the steps for performing the ELISA test?
What are hypersensitivities?
Allergies. Exaggerated immune response to what should be a relatively harmless Ag (allergen)
What are the types of hypersensitivities?
Types I, II, III - Humoral (involve Ab)
Type IV - Cell-mediated (involves Tc cells)
What is type I hypersensitivity?
Anaphylaxis
What happens in your first exposure to allergen in type I hypersensitivity?
Sensitization
- IgE antibodies made instead of IgG against allergen
- IgE Ab bind to mast cells and basophils
What happens during the second and subsequent exposure to an allergen in type I hypersensitivity?
- allergen binds to 2 IgE Ab
- Mast cells/basophils release histamine, leukotrienes, prostaglandins, etc.
- Inflammatory symptoms appear immediately
What is localized hypersensitivity?
only affects the allergen’s region of entry
What is systemic hypersensitivity?
allergen gets into blood and creates an all-over inflammatory reaction
- anaphylactic shock
What is the treatment for type I hypersensitivity?
- anti-inflammatories, anti- histamines
- Epinephrine
How does desensitization work for Type I hypersensitivity?
- application of small doses of allergen
- causes Ab class to switch from IgE to IgG (doesn’t bind to mast cells and basophils)
What is type II hypersensitivity?
Cytotoxic reactions
- Ab (IgG) binds the allergen and activates the complement system to kill those cells (MAC)
What is an example of type II hypersensitivity? What is the treatment?
Hemolytic disease of newborn
- blood mixes when the placenta detaches at birth (anti-D)
Treatment: RhoGAM- injection prevents sensitization (given during pregnancy and at birth)
What is Type III hypersensitivity?
Immune complex reactions
- Ab-Ag complex settles in tissues, triggers inflammatory reactions
e.g. Glomerulonephritis following untreated Streptococcus infection
- M proteins + IgG Ab complex settle in kidneys
What is type IV hypersensitivity?
Cell mediated
1st exposure: sensitization
- Tc cells (memory T cells) recognize the allergen
2nd and subsequent exposures
- Tc cells migrate to site of exposure
- delayed reaction (hours to days)
What is an autoimmune disorder?
Occur when the immune system sees self-antigens as foreign and attacks them
- often triggered by traumatic event (even vaccine)
- usually occur later in life
- 2/3 of sufferers are women
What are the possible origins of autoimmune disorders?
- problem with clonal deletion
- non-self Ag similar to some self Ag -> generation of Ab that bind to both
What is type II autoimmune disorder?
IgG attach to cells/tissues
What is Grave’s disease?
Type II Autoimmune
Ab bind TSH receptors in Thyroid -> causes hyperthyroidism
What is Myasthenia Gravis?
Type II Autoimmune
Ab block ACh receptors at neuromuscular junction -> flaccid paralysis
What is type III autoimmune disorder?
Ab-Ag complexes form
What is Lupus Erythematosus?
type III autoimmune disorder
complexes settle in many tissues “butterfly rash)
What is Rheumatoid Arthritis?
type III autoimmune disorder
complexes settle in joints
What are type IV autoimmune disorders?
Tc cells attack normal cells
What is thyroiditis?
type IV autoimmune disorder
leads to hypothyroidism
- less TH
What is Type I diabetes?
type IV autoimmune disorders
Islet of Langerhans cells (normally produce insulin) killed in the pancreas
What is immunosuppression?
partial or complete suppression of the immune system
Genetic - SCID syndrome
Acuired - AIDS
What type of immunosuppressant medications can be taken to treat autoimmune disorders?
Corticosteroids (Cortisol)
- dampens innate defenses
Cyclosporin
- inhibits B-cell and T-cell activation and differentiation
