Quiz 3 Flashcards
In what type of antibody responses do marginal zone B cells participate in?
T-independent antibody responses
Marginal zone B cells can only produce what antibody type?
IgM
Are IgM antibodies low or high affinity when induced by a polysaccharide vaccine?
Low affinity
What chemical change is made to a polysaccharide vaccine to generate a conjugate vaccine?
Which type of vaccine is the most effective, but also tends to elicit the most side effects?
Live attenuated vaccines
How does a live-attenuated vaccine induce immunity? Give an example
Virus strains are selectively grown to be weaker or “attenuated” and can be used to induce an immune response against other strains, due to cross-reactivity
The principle of cross-reactivity allowed for immunity against polio after being administered a cowpox vaccine
Which vaccines are classified as live-attenuated vaccines?
Yellow fever
Measles
Mumps
Rubella
Polio
Varicella
How does a killed or inactivated vaccine induce immunity?
A human virus is used to infect animal cells and then is formalin-fixed (killed); this can induce an immune response
What are some examples of a killed or inactivated vaccine?
Pertussis (Bordetella pertussis)
Paratyphoid fever (Salmonella paratyphi)
Typhus fever (Rickettsia prowezekii)
Cholera (Vibrio cholerae)
Plague (Yersinia pestis)
Influenza
Rabies
How does a toxoid vaccine induce immunity?
Uses a toxin as an antigen to initiate an immune response
What are some examples of toxoid vaccines?
Diphteria
Tetanus
How does a recombinant protein induce immunity?
A DNA encoding antigen is inserted into DNA of a host cell (usually yeast or bactera) in order to mass produce antigen to trigger an immune response
What are some examples of a recombinant protein vaccine?
Hepatitis A
Hepatitis B
Human papillomavirus
How does a polysaccharide vaccine induce immunity?
Bacterial carbohydrate chains isolated from various serotypes can produce a T-cell independent immune response to produce low affinity IgM
What are examples of polysaccharide vaccines?
Meningitis (Neisseria meningitidis)
Bacterial pneumonia (Streptococcus pneumoniae)
What are examples of conjugate vaccines?
Meningitis (Haemophilus influenzae)
How does a conjugate vaccine induce immunity?
A conjugated vaccine is able to induce a T cell response due to the protein attached to the polysaccharide. This allows for formation of a germinal center -> affinity maturation & isotype switching -> high affinity IgG and better overall immunological memory
What is the purpose of adjuvant in vaccines?
To induce inflammation via:
Macrophage activation
Recruitment of inflammatory cells
Cytokine production
*Overall mechanism not well understood
What type of enzyme is reverse transcriptase?
An RNA-dependent DNA polymerase
What is the chief benefit of using ELISA to diagnose HIV?
ELISA is highly sensitive (99.5%)
What is the chief benefit of testing for HIV1/2 or p24 antigen?
Testing is highly specific (>99%)
In what period of HIV infection are false negatives most likely to be detected?
The window period
In what situations would HIV testing be most likely to be falsely positive?
Pregnancy
Influenza vaccine
Autoimmune disease
Where can Mycobacterium avium complex bacteria be found? What symptoms does infections produce? How can it be diagnosed?
Ubiquitous in the environment
Sx
-fever
-night sweats
-weight loss
-diarrhea & abdominal pain
IRIS: lymphadenitis
Dx
-Culture of organism from blood or sterile body site