immunology Flashcards
what is passive immunity; give examples
Administration of preformed immunity from one person to another
ex.:
cross-placental transfer of antibodies from mother to child (e.g. measles, pertussis)
transfusion of blood or blood products including immunoglobulin (e.g. Hep B)
injection of immunoglobulins
what is Human normal immunoglobulin (HNIG)
an injection of the pooled plasma of donors which contains antibodies to infectious agents that are currently prevalent in the general population.
what type of immunisation do vaccines stimulate
active immunisation
define primary and secondary vaccine failure
Primary vaccine failure – person doesn’t develop immunity from vaccine.
Secondary vaccine failure – initially responds but protection wanes over time
Define active immunization
administering a toxoid to stimulate the immune system to produce antibodies
What are the three ways of inducing active immunization
Using a whole virus
Using parts that trigger the immune system (antigens)
Using the genetic material of the pathogen
Name two classes non-living vaccines
Whole killed and toxoid
Define whole killed vaccines and explain limitations
Vaccines using the inactivated bacteria/viruses
Limitations:
-whole pathogens can cause excessive adverse reactions
- immune responses are not always as good as response to actual infection (no CD8 TC) responses
- usually need at least 2 doses
Give examples of whole killed bacterial vaccines
diphteria
Tetanus
Pertussis
Cholera
What is pertussis
Whooping cough
Give 3 examples of whole killed viral vaccines
like the actual diseases
Polio, influenza, hep A, rabies, sars-cov-2
Define live attenuated vaccines
The organism is cultured in such a way that it’s virulescence is “attenuated” (does not cause disease when put in humans). The organism is put in host, allowed to replicate and induce an immune response which is protective against the wild type organism
Which provides better protection: whole killed or live attenuated vaccines
Live attenuated
what are the advantages of live attenuated
immune response mimics real infection more closely
lower and fewer doses required
oral administration –> more favorable
what are the disadvantages of live attenuated vaccines?
Often impossible to balance attenuation and immunogenicity
Reversion to virulence
immunocompromised hosts might have more side effects from the vaccine
give bacterial examples of live attenuated vaccines
Mycobacterium bovis and Salmonella typhi
give viral examples of live attenuated vaccines
MMR and poliomyelitis
what are recombinant protein vaccines?
genetically engineered proteins produced from bacteria yeast or mammalian cells
examples of recombinant protein vaccines
hep B
HPV
Sars-CoV-2
what are synthetic peptide vaccines?
peptides synthesised directly using a machine
what are live attenuated vector vaccines?
These vaccines also use live attenuated viruses but are modified to carry genetic material from the disease-causing pathogen rather than using the pathogen itself.
example of live attenuated vector vaccine
Sars-CoV-2
what are dna vaccines and how do they work
a vaccine with plasmids that encode for a foreign protein of interest which is injected directly
DNA goes to the nucleus, gets transcribed, and the foreign protein gets displayed by MHC to stimulate an immune response
what are mRNA vaccines?
mRNA of foreign protein is injected into the body
cells use the instructions to make the viral protein, prompting the immune system to recognize it as foreign and generate an immune response, including the production of antibodies.
If the vaccinated person later encounters the actual virus, their immune system is primed to recognize and fight it off more effectively
what is the complement system?
a system of proteins which work together to enhance the inflammatory response
what are the three ways of activation of the complement system
- classical -> antibody-antigen binding
- alternative -> complement proteins bind to microbe
- lectin –> mannose binds to lectin on microbe
what chemokines does the complement system make and what are their roles
C3a + C5a –> make chemokines
C3b –> opsonisation
MAC –> membrane attack complex –> lyses microbes directly
what percentage of blood is plasma
55%
what percentage of blood are rbc
45%
what % of blood plasma are the leukocytes and platelets
less than 1%