Vaccines Flashcards
Functions of Vaccines
- Pep the immune system for war by providing best “as close to real life” training
- Stimulates adaptive immune system into creating MEMORY
Cell types involved in Immuno Memory
- Memory B cells
- Memory Helper T cells
- Memory Killer T cells
Note that Memory B and Memory Helper T can be produced even when no immune cells have been infected by attacker
Mechanism of vaccination
- Majority of vaccines are developed without understanding the immunological mechanism for inducing immunity
- Vaccines are believe to confer protection through neutralizing antibodies
- But precise mechanism is still in research
requirements for immunity to occur
B and T cells against the pathogen must be developed
• not all diseases will cause immune system to develop resistance against reinfection
Passive immunity
when pre-formed antibodies are transferred to the patient. Will give temporary immunity.
• i.e. Mother to fetus
why some diseases will not lead to immunity
- pathogen can mutate and existence multiple serotypes
- pathogens that cause persistent or latent infection are challenging for immune system
classifications of vaccines
- group 1 = live attenuated vaccines
- group 2 = subunit vaccines, toxoid vaccines, aldehyde vaccines, conjugate vaccines
live attenuated vaccines
Weakened version of pathogen which mimics the kind of protective immunity found in people that have survived the live infection. Generally are successful in creating long-term immunity
Types of vaccines
non-infectious, attenuated, and carrier
non-infectious vaccines
will cause the body to make Memory B and Helper T cells, but do NOT cause production of memory Killer cells
- design not to infect the host
- includes: killed vaccines (formaldehyde), bacterial toxins (aluminum), parts of pathogens
examples of live attenuated viruses include
mumps, measles, and rubella
Carrier vaccine
- introduce a single gene from a pathogenic microbe into a virus that doesn’t cause disease
- carrier then affects the host’s APC
- APC produces a pathogenic microbe protein and presents it on MHC I
- results in a “Trojan horse” like effect by creating Memory B, Memory Helper T, and Memory Killer T cells
HIB
Haemophilus Influenza type B: prevents bacterial meningitis and pneumonia
PcV
Pneumococcal Conjugate Vaccine: prevents streptococcal pneumonia
DTaP
Diptheria Tetanus and Pertussis: combined vaccine
RV
Rotovirus
IPV
Inactivated Poliovirus
MCV4
Meningococcal Vaccine: against Neisseria meningitides
Adjuvant means
“helper”
Immunological adjuvant
helps stimulate the immune system, but will not have any antigenic effect by itself. Merely enhances the quality of immune response by CAUSING MILD INFLAMMATION
Th1
Helpers cells that respond to VIRAL or BACTERIA attacks. Responds by classical cytokines (TNF, IFN-γ, IL-2) with the goal of activating macrophages and natural killer cells.
Th2
helper cells that respond to PARASITIC attack or bacterial food CONTAMINATION. Response by informing that intestines are under attack (IL-4, IL-5, IL-13) with the goal of proliferating T cells.
Thimerosal
mercury containing preservative used in some vaccines. No evidence it causes harm, but does cause minor reactions (swelling and redness). But American Academy of pediatrics said it should be reduced or eliminated from vaccines as a precautionary measure
Aluminum
aluminum salts can be emulsified with the antigen thereby creating a gel like substance that induces Th2 response. Uses IL-16 for microglia activation and Induces chemokines in macrophages, monocytes and granulocytes
is aluminum a toxin?
Exposure to aluminum occurs via numerous routes (food, water, pharmaceuticals, vaccines). It accumulates in mitochondria and nucleus, but there is no physiological need for it. Only 0.3% of orally administered aluminum is absorbed in the G.I. tract. Only toxic when aluminum bypasses GI barrier (Ie intravenous infusion).
Antacids
some contain aluminum
bioavailability of aluminum from food
only 0.1%
aluminum and autism
countries with the most autism have highest exposure to aluminum from vaccines. Aluminum correlates with increased autism prevalence in the United States
“common” individual vaccines include
“PP R HIV”
- pneumococcal disease (Pc Vaccine), pertussis (DTaP Vaccine),
- rotavirus
- human papilloma virus (HPV), influenza, Varicella
“infectious” individual vaccines include
“MMR V”
- mumps, measles, rubella
- Varicella
microglia
- macrophage of the CNS
- 20% of brain glial cells
- constantly sampling surrounding environment to assure homeostasis
- can be activated in response to stimuli
- regulates release of pro-inflammatory cytokines, and excitatory amino acids (glutamate)
astrocytes
most abundant cell in human brain that function to:
- structural and nutritional support
- regulates environment, blood flow
- assist in synaptic transmission, myelination, and repair
- long-term potentiation (memory)
aluminum effects on glial cells
microglia and astrocytes are sites of potential aluminum accumulation. Thus increase aluminum can increase both pro-inflammatory cytokines and glutamate (excitatory molecule) in the brain
Macrophage
garbage collector what rest, APC and killer when activated. Ruthless killer when hyperactivated
Microglia stages
Resting = sampling the surrounding microenvironment
Primed = no increase release of cytokines, interferons or excitotoxins
Hyperactive = released pro-inflammatory cytokines, chemokines and exitotoxins
Herd Immunity
protection provided to ALL individuals in a pop due to the inability of a pathogen to effectively spread when larger proportion of individuals are resistant
- reduces probability of transmission
- even unvaccinated members will be protected b/c their p[infection] = low
- effect only observed when vaccination is frequent in pop
- minimum 75%, but typically 85%
