Immunology 3 Flashcards
Two types of immunizaton
Active immunization
Passive immunization
Develop of own protective cells calledantibodies uponadministration of vaccines or toxoids
Active immunization
Synonymous with vaccination
Active immunization
Artificially acquired
Induce active immunity by administering vaccinesor toxoid
Lasts for weeks, months, years
Active immunization
Importance of immunization
Protect yourself
Protect the people around you
Vaccines promote healthby helping people stay healthy
Vaccine have expansive reach to protect individuals, communities & entirepopulation, especially those who are not allowed to be immunized
VACCINES SAVE LIVES & COSTS
Things to consider in immunization
Age Medical History (seizures) Immunization History Type of vaccine given Current medical conditions (Moderately or severely ill,fever, immunocompromised) Allergic reactions
Contain attenuated microorganisms ortheir parts to which immune system responds
Vaccine
Inactivated toxins; not harmful but retainimmunologic activity
Toxoid
True or False.
Immune response is the same as an individual withdisease but disease doesn’t occur.
True
True or False.
In vaccines, epitopes are retained but lost ability to cause disease.
True
True or False.
Vaccines cannot be used to prevent disease after a person hasbeen exposed.
True
True or False.
In active immunization, the time required for immunity to develop may be greaterthan incubation period of disease except rabies vaccine (long incubation and active immunization can be used).
True
Characteristics of an effective vaccine
- Low levels of adverse effects or toxicity.
- Protect against exposure to natural wild forms ofpathogen.
- Stimulate both antibody (B-cell) response andcell-mediated (T-cell response)
- Should have long term lasting effects
- Should have not require numerous doses or boosters
- Should be inexpensive, with relatively long shelf lifeand easily administered
Preparation of vaccines
- Live Attenuated cells or viruses
- Killed whole cell or inactivated virus
- Subunit Recombinant, Polysaccharide and conjugatevaccines
- Toxoid
Examples of live attenuated cells or viruses
Virus: Sabin polio vaccine, MMR, small pox,yellow fever, chicken pox, oral polio vaccine,rotavirus, influenza (intranasal)
Bacteria: TB vaccines, Oral typhoidvaccine
Examples of killed whole cell or inactivated virus
Virus: Rabies Vaccine, Sulk polio vaccine, Hepa A, Influenza
Bacteria: Cholera, Pneumococcal pneumonia, Pertussis vaccine, Typhoid,Plague
Example of subunit recombinant, polysaccharid and conjugate vaccines
Capsule of meninggococcus &pneumococcus, surface protein of Hepa B virus
Examples of toxoid
Diptheria
Tetanus
Vaccine derived from disease causing viruses or bacteria, use living but weakened microbesand closely mimics an actual infection
Live attenuated cells or viruses
General rule of vaccination
The more similar a vaccine is to the disease causing form of an organism, the better the immune response to the vaccine.
True or False.
To produce immune response: live attenuatedvaccines must replicate/grow in the vaccinatedperson. Small dose of virus/bacteria is administered whichreplicates in the body enough to stimulate an immuneresponse but aims not to cause disease.
True
If a vaccine can cause the disease but in a milder form, it is called
Adverse reaction
Vaccine that use microbes that have been killed or inactivated with formulation of phenol, radiation, heat (doesn’t destroy antigenicity) and requires larger doses or more boosters
Inactivated vaccine
Vaccines that use antigenic molecules derived from bacterial cells or viruses, give very strong immune response and can be used by everyone.
Subunit, recombinant, polysaccharide and conjugate vaccines
Use only antigenic fragments (typically a surfaceprotein of microbes that best stimulate an immune response against the pathogen from which it is derived.
Subunit
Long chain of sugar molecules that make up the cell wall of the bacteriabut not consistently immunogenic to children <2y.o.
Capsular Polysaccharide Vaccines
Examples of capsular polysaccharide vaccines
Pneumococcal, Meningococcal, Salmonella typhi, Haemophilius type b (Hib), Pertussis (part of theDTaP combined vaccines)
Subunit vaccines produced by genetic engineeringtechniques
Microbes are programmed to produce the desired antigenic fraction
Recombinant vaccines
Examples of recombinant vaccines
Hepa B vaccine (Portion of protein viral coatproduced by genetically engineered yeast), HPV,Influenza
Combine a weak antigen with a strong antigen ascarrier so that the immune system has a stronger response to the weak antigen
Conjugate vaccine
Develop due to poor immune response of children to polysaccharides.
Given to children less than 2 years of age.
Conjugate vaccine
True or False.
In conjugate vaccines, the antigen of some pathogenic bacteria does not elicit a strong response from the immune system, so a vaccination against this weak antigen would not protect the person later in life.
True
Examples of conjugate vaccines
Hib conjugate vaccine (Haemophilus influenza)
Streptococcus pneumoniae vaccine
Neisseria meningitidis vaccine
Inactivated toxins
Directed at the toxins produced by a pathogen
Consist of a purified fragment of bacterial exotoxin that is most antigenic
Requires a series of injections of full immunity followed by boosters of 10 yrs
Toxoid
True or False.
Boosters are given for short lived immunity.
True
The first shot stimulates the
Primary immune response
The second shot stimulates the
Secondary immune response
True or False.
1st shot is not good for protection just stimulates the primary immune system but the 2nd and 3rd provides protection.
True
Functions of booster shots
Increase number of Ab
Expand memory cells population
Objective of different routes of administration
Deliver Ag stimulus to body site affected by the disease
Routes of administration
Injected (IM, subcutaneous, intradermal routes)
Oral (Rotavirus)
Intranasal (spray or drops; LAIV)
Any compound that enhances immunogenicity and prolong antigen retention at the injection site
Adjuvant
Examples of adjuvant
Aluminum hydroxide salts, Freud’s adjuvant (mineral oil, water, extracts of mycobacteria)
It precipitates the antigen and holds it in the tissues so that it will be released gradually which gives more time for contact with macrophages and lymphocytes.
Adjuvant
Storage of vaccines
Important to maintain effectiveness
Store in cold ares
Used in certain prescribed time
Ready made Ab are introduced into an unprotected individual; given immunity to non-immune person exposed to the disease or at least lessen severity of disease
Passive immunity
Also called antisera
Passive immunity
Serum containing preformed antibodies collected from human blood plasma donors or from horses intentionally exposed to disease agent for temporary immunity
Antisera
Administer preparations of antisera
- Immune Serum Globulins (ISG, Gamma Globulins)
- Hyperimmune serum
- Antitoxin
Contains pooled gamma globulins (IgG antibody fraction from thousands of adult donors) which provide passive immunity to common disease
Homologous pooled human antibody (Immune serum globulins; gamma globulins)
Uses of HPHA
Post exposure prophylaxis to measles, hepatitis A, mumps
Treatment of certain congenital immunoglobulin deficiencies
From a more defined group of donors
Contains high titers of specific kind of Ab
Made from donated plasma of humans with high levels of Ab of interest
Contains other Ab in lesser quantities
Specific Immune Globulins (Hyperimmune Sera)
Donors of SIG
Patients who are convalescing (getting better) in hyperimmune state
Uses of SIG
Postexposure prophylaxis of Hep B, rabies, tetanus, and varicella
Contain Ab against specific toxins
Produced in animals (horses) and contains antibodies against only one antigen
Heterologous Hyperimmune Serum (Antitoxin)
Use of HHS
Botulism and Diphtheria
Adverse effect of HHS
Patient may experience serum sickness (immune reaction to horse protein): fever, weakness, hives, itching, joint pain, rash, swollen lymph nodes
Vaccines in progress
DNA vaccines
Recombinant vector vaccines (Platform-based vaccines)
Involves the direct introduction of a plasmid containing the DNA sequence encoding the antigen(s) against which an immune response is sought into appropriate tissues
Relies on the in situ production of the target antigen
DNA vaccines
Advantages of DNA vaccines
Easy and inexpensive to make Produce strong, long-term immunity Stimulation of both B- and T-cell responses Improved vaccine stability Absence of any infectious agent Relative ease of large-scale manufacture
These are live replicating viruses that are engineered to carry extra genes derived from a pathogen- and these extra genes produce proteins against which we want to generate immunity
Recombinant vector vaccines (Platform-based vaccines)
Use a harmless virus or bacterium as a vector, or carrier, to introduce genetic material into cells
Recombinant vector vaccines
Act like a natural infection, so they’re especially good at teaching the immune system how to fight germs and currently used in vaccines in animals
Recombinant Vector vaccine
Objective of clinical immunology diagnostic testing
To provide laboratory testing to support the diagnosis and monitoring of patients with immune disorders
Types of Antibody evaluation assays
ELISA
Immunofluoresence
Immunoblot
AB evaluation assay widely used for biological products (antigen, antibody, hormones, peptides, antibody-antigen detection)
ELISA
Uses of ELISA
Sensitive and specific in detecting antibodies to a number of diseases (HIV, Syphilis,)
Detect auto-antibodies present in patients with systemic and organ-specific auto-immune diseases (SLE, scleroderma, Sjogren syndrome)
Principle of ELISA
Can also detect Antigens
Antigen attach to antibodies bonded to enzymes that may catalyze a reaction and result in a change in color that is measured colorimetrically and converted to numeric values
Results of ELISA
Chance in color: positive result
Lack of color: antigen was not present
True or False.
Depending on the antigen-antibody combination, the assay is called direct ELISA, indirect ELISA, sandwich ELISA, competitive ELISA, etc.
True
A target protein is immobilized on the surface of microplate wells and incubated with an enzyme-labeled antibody to the target protein (or a specific antigen to the target antibody). After washing, the activity of the microplate well-bound enzyme is measured.
Direct method
A target protein is immobilized on the surface of microplate wells and incubated with an antibody to the target protein (the primary antibody).
Followed by a secondary antibody against the primary antibody.
After washing, the activity of the microplate well-bound enzyme is measured.
Direct ELISA
True or False.
Although indirect ELISA requires more steps than direct ELISA, labeled secondary antibodies are commercially available, eliminating the need to label the primary antibody.
True
An antibody to a target protein is immobilized on the surface of microplate wells and incubated first with the target protein.
Then with another target protein-specific antibody, which is labeled with an enzyme .
After washing, the activity of the microplate well-bound enzyme is measured. The immobilized antibody (orange) and the enzyme-labeled antibody (green) must recognize different epitopes of the target protein.
Sandwish ELISA
True or False.
Compared to direct ELISA, the sandwich ELISA (combining antibodies to two different epitopes on the target protein) has a higher specificity.
True
True or False.
Sandwich ELISA is useful for applications that require a high accuracy.
True
An antibody specific for a target protein is immobilized on the surface of microplate wells and incubated with samples containing the target protein and a known amount of enzyme-labeled target protein.
After the reaction, the activity of the microplate well-bound enzyme is measured.
Competitive ELISA
True or False.
When the antigen level in the sample is high, the level of antibody-bound enzyme-labeled antigen is lower and the color is lighter.
True
True or False.
When antigen level is low, the level of antibody-bound enzyme-labeled antigen is higher and the color, darker. The graph above and to the right illustrates the correlation between absorption and antigen levels in samples.
True
True or False.
When a target antigen is a small molecule, such as histamine, pesticide, and dioxin, two antibodies cannot simultaneously bind to the antigen in sandwich ELISA.
True
True or False.
Competitive ELISA is useful for the measurement of low molecular weight targets.
The process in which antibodies are labeled with a fluorescent dye (fluorochromes) causing the presence of an antibody to observed using UV light in a fluorescence microscope.
Immunofluorescence
Two types of immnofluourescence
Direct
Indirect
Direct or Indirect IFS.
Detects antigens in tissues
Direct
Direct or Indirect IFS.
Detects specific antibodies in individuals’s serum
Indirect
Direct or Indirect IFS.
Diagnose enterohepatic E. coli, N. meningitidis, S. typhi, Shigella sonnei, Listeria monocytogenes, H. influenzae type b, and Rabies virus
Direct
Direct or Indirect IFS.
Detect presence of Ab in serum following exposure to microorganisms like Treponema pallidum (Treponema antibody absorption, FTA-ABS)
Indirect
Direct or Indirect IFS.
Primary (direct) immunofluorescence uses a single, primary antibody, chemically linked to a fluorophore which recognizes the target molecule (antigen) and binds to the epitope.
Direct
Direct or Indirect IFS.
Secondary (indirect) immunofluorescence uses two antibodies:
1. The unlabeled first (primary) antibody specifically binds the target molecule
2. Secondary antibody, which carries the fluorophore, recognizes the primary antibody and binds to it
Indirect
Direct or Indirect IFS.
Positive Result: Fluorescing cells/specks , which indicate Ab-Ag complex
Direct
AKA Western blot
Used to identify an antigen in a complex mixture of proteins (Eg. microorganisms like HCV and Lyme disease)
Bands are compared to known positive and negative samples
Immunoblot
Procedures of Immunoblot
- Protein molecules are separated according to their charges and molecular sizes using a method called gel electrophoresis
- Following separation, the proteins are transferred from the gel onto a blotting membrane
- Membrane is incubated with serum sample
- If serum contains specific Ab that reacts with the protein on membrane, Ab will remain on membrane
- Membrane is washed and incubated with substrate mixture
- Enzyme and enzyme substrate mixture allows for colorimetric detection
Confirmatory test for HIV
Immmunoblot
Tools used to evaluate cellular responses
Flow cytometry
Agglutination test
Laser based method
Used for analysis of cells and cell components (Immunophenotyping of cell population)
Flow cytometry
Procedure or flow cytometry
- Single cell suspensions are passed through a laser beam for sensing
- As cells pass through the laser they scatter light
- If cells contain fluorescent molecules this will be detected
- Scattered light and fluorescent light information are then analyzed
Demonstrate the presence of the antigen
In addition to causing precipitation of soluble molecules and flocculation of molecules in suspension, antibodies can also clump together cells or particles (e.g., antigen-coated latex beads)
Agglutination
Clinical method to detect certain antigens or antibodies in a variety of bodily fluids such as blood, saliva, urine, or cerebrospinal fluid.
Latex agglutination test
Observed when a sample containing the specific antigen (or antibody) is mixed with an antibody (or antigen) which is coated on the surface of latex particles
Latex agglutination
The reaction between a particulate antigen and an antibody results in visible clumping
Agglutination
Detects microbial and viral infections, autoimmune diseases, hormones, drugs and serum proteins
Particle agglutination
The sample to be tested is sent to the lab where it is mixed with latex beads coated with a specific antigen or antibody. The clumping of latex beads (agglutination) indicates the presence of suspected particles.
Particle agglutination
