Vaccine Immunology Flashcards
What is vaccination?
Providing protection by utilizing pre existing components of the immune response or by inducing the generation of antigen specific memory cells
What are the types of immunization?
Active and passive. Active is the most common
Discuss active immunization
This is the injection of an antigen, often requiring additional components, immune response is generated in vivo, takes time to develop but provides long term protection due to generation of memory T cells and B cells. Potential to develop cell mediated and humoral response.
Discuss passive immunization
It is injection of pre formed antibodies, immediate protection but short term, only provides humoral immunity- pathogen needs to be susceptible to antibody mediated destruction. There’s a risk of adventitious pathogen transfer.
What is horse antisera (passive immunization) used against?
Snake venom, botulism toxin, diphtheria toxin
What is pooled human Ig used against? What is humanized monoclonal used against? (Passive immunization)
Hepatitis A or B, measles, rabies, tetanus, varicella zoster
Respiratory syncytial virus (RSV)
Dimeric secretory IgA is particularly effective at?
Preventing bacterial colonization
What are the general requirements for a successful vaccine?
Appropriate adaptive immune response, effective, stable, safe, inexpensive
Which infectious agents were declared eradicated following global vaccination programs?
Smallpox in humans in 1979
Rinderpest in cattle in 2011
What are the components needed in a vaccine?
- Antigen: whole organism(live attenuated or killed), subunit
- Carrier: provides helper T cell epitopes
- Adjuvant: non specifically stimulates a specific immune response; depot + DC activator causing up regulation of co stimulatory molecules CD80, CD86
Give examples of adjuvants
Aluminum salts, AS03, AS04, MF59, virosomes
Give an example of a vaccine aimed at preventing infection
Polio (OPV)
Give an example of a vaccine aimed at controlling existing infection
Zoster
Give an example of a vaccine aimed at preventing disease development post exposure
Rabies
Give an example of a vaccine aimed at preventing fetal infection
Rubella
Give an example of a vaccine aimed at preventing or controlling cancer
HPV/HBV
What is the function of an adjuvant in a vaccine?
Stimulates antigen uptake and stimulates an immune response
What are the advantages of live attenuated vaccines?
- Mimic natural infection thus providing appropriate responses
- Stimulate both humoral and cell mediated immunity
- Typically generate long term immunity with reduced need for booster immunization
What are the disadvantages of live attenuated vaccines?
- There’s a slight potential to revert back to virulent form
- Often require refrigeration
- Potential for spread from vaccinee
- Contraindicated in immunocompromised due to risk of significant pathology
Give examples of live attenuated vaccines
Viruses Intranasal influenza Measles mumps rubella OPV Rotavirus Varicella zoster virus Yellow fever
Bacterial
Oral typhoid vaccine Ty21a
Bacilli Calmette Guerin
What are the advantages of inactivated vaccines
- Relatively easy to manufacture
- No possibility of reversion to virulent pathogen
- Safe for use in the immunocompromised
What are the disadvantages of inactivated vaccines?
- Adjuvants required
- Typically requires initial 2-3 immunizations and then relatively frequent boosts
- Immunity can be short lived and predominantly humoral with poor cell mediated immunity
Give examples of inactivated vaccines
Hepatitis A virus Influenza virus Japanese enecephalitis virus Poliovirus Rabies Tick borne encephalitis
Give examples of subunit vaccines
Viruses
Hepatitis B
Human papillomavirus
Bacteria
DTaP
Meningococcal serogroup B vaccines
What is the Gardasil-9 vaccine given to females 9-26 years old for?
Prevention of cervical, vulvar, vaginal, anal cancer and genital warts
What is the Gardasil-9 vaccine given to males 9-26 years old for?
Prevention of anal cancer and genital warts
What are toxoid vaccines?
Chemically inactivated bacterial exotoxins, protect from disease but not infection. Examples are tetanus toxoid San diphtheria toxoid.
What do conjugate vaccines do?
They comprise polysaccharides coupled to protein. Tetanus or diphtheria is usually the protein. Converts T independent response to T dependent response.
What are examples of conjugate vaccines?
Hib
Meningococcal conjugate vaccines
Pneumococcal conjugate vaccine
Pertactin is an example of?
Bacterial outer membrane protein (OMP)
What are the two types of genetic change the influenza virus can undergo?
Antigenic drift and antigenic shift
Antigenic drift refers to point mutation
Antigenic shift refers to exchange of genetic material
Which antigens in the influenza virus can undergo point mutations?
The neuraminidase and hemaglutinin antigens
Give an example of antigenic shift
An exchange between human influenza virus and avian influenza virus. Creates a new strain of human influenza virus.
What is the BCG vaccine?
Attenuated live Bacille Calmette Guerin strain of Mycobacterium bovis for TB, used in countries with high prevalence of TBto prevent childhood tuberculosis meningitis and miliary disease. Considered only for health care workers for exposure and children with negative TB skin test and at high risk
What does success of a HIV vaccine require?
Requires identification of immunogens and immunization strategy that induces broad and long lasting CTL immunity together with broadly neutralizing antibodies
