Chapter 11: Immunological Memory And Vaccination Flashcards
In a person with ________________ memory the second infection is usually cleared before it produces any symptoms
- immunological
The __________ formed during a primary immune response prevent reinfection for several months after disease.
- antibodies
Immunological memory is stained by _________ clones of long-lived memory T cells and B cells
- clones
- both effector B and T cells and memory B and T cells are produced during a primary immune response
___________ against a pathogen can generate immunological memory that persists for life
- vaccination
Long lived clones of memory ____ and ______ cells are produced in the _______________ immune response
- B and T
- primary
Pathogen-specific memory B cells are more abundant and make better antibodies in _________ response than do naive B cells
- secondary
- key features that make the secondary response stringer than the primary response are the greater numbers of antigen specific B cells present at the start of the secondary response and the preferential use of isotype-switched clones of B cells that express higher-affinity immunoglobulins as a result of somatic hypermutation and affinity maturation
Only memory B cells, and not naive B cells, participate in the secondary immune response. How?
- IgG antibody suppress the activation of naive B cells by cross linking the BCR and FC-gamma-RIIB1 on the B cell surface
Immune- complex mediated inhibition of naive B cells is used to prevent hemolytic anemia of the newborn
- Rhesus blood group antigen (Rh) expressed by erythrocytes is absent in a minority of individuals.
- Rh- mothers carrying Rh+ fetuses become exposed to fetal erythrocytes (in the first pregnancy ) and make Rh- specific antibodies that pass to the fetal circulation and cause fetal red cells to be destroyed (in second pregnancy)
Passive immunization with anti-Rhesus antigen IgG prevents hemolytic anemia of the newborn.
- the immune complexes of fetal erythrocytes coated with IgG prevent a primary B cell response from being made to the Rh antigen
In the response to influenza virus, immunological memory is gradually eroded.
- highly mutable viruses such as influenza gradually escape from immunological memory without stimulating a compensatory immune response
The procedure in which the adaptive immune system is manipulated in an antigen-specific manner to mimic infection by particular pathogen and stimulate protective immunity against it without causing the disease itself is a…
- vaccination
Edward Jenner created a vaccination with the use of cow pox
- used cow pox to vaccinate others against smallpox
Vaccine is…
- the material used for vaccination
- vaccus in latin means cow
Viral vaccines are made from ____________ viruses or viral ___________
- whole
- components
Vaccines today are composed of preparations of the disease causing virus with the ability to cause diease being weakened or destroyed
- chemical treatment with formalin, physically heating, or irradiation.
- removes the ability of the virus to replicate
- killed or inactivated virus vaccines
Examples:
Influenza
Rabies
Salk Polio
Small pox (variola)
- contagious and sometimes fatal
- highly contagious disease caused by variola virus, a dsDNA orthopoxvirus of the Poxviridae; virus is slightly larger than the smallest bacterium; replicates in host’s cell’s cytoplasm
- pink-red macules appear on face and trunk
- they become papules and fluid filled vesicles
- vesicles become pustules that break open and emit puss, leaving pitted scars
- smallpox is one of the most dangerous weapons of bioterrorism
- vaccines ceased in the US in 1972 after eradication occurred (many people not immune)
Vaccination with ____________ virus elicits neutralizing antibodies that react with antigenic determinants shared with __________ virus
- cowpox
- smallpox
- the shared antigenic determinants of cowpox also elicit protective T-cell immunity against smallpox
Live-Attenuated Virus Vaccines
- live virus that has mutated so that it has a reduced ability to grow in human cells and is no longer pathogenic to humans
- these vaccines are more potent at eliciting protective immunity than the killed virus vaccine
- it can still replicate and mimic a real infection although they are not pathogenic
- most of the viral vaccines currently used to protect human are live-attenuated
Examples:
Measles
Mumps
Polio
Yellow fever
How are attenuated viruses made?
- selected by growing human viruses in non-human cells
Subunit Vaccines
- are made by using surface components of the virus
Examples:
Hepatitis B virus vaccine uses hepatitis B virus surface antigen (HBsAg)
Bacterial Vaccines
- are made from whole bacteria, their secreted toxins or capsular polysaccharides
- many bacteria produce toxin that cause the disease
- need to stimulate an antibody response against the toxin
- Diphtheria toxin and tetanus toxin are inactivated with formalin to produce a toxoid, which is used in vaccine preparations
- Toxoids are similar to the toxin but do not cause disease
- most bacterial vaccines are subunit vaccines
Current schedule for recommended childhood immunizations in the US include multiple vaccinations to develop long term memory….
- B cells and T cells
Adjuvants nonspecifically enhance the immune response
- they are substances that induce inflammation by antigen independent mech
Most effective adjuvant in experimental immunology is Freund’s Complete Adjuvant
- is an emulsion of killed mycobacteria and mineral oil into which antigen are vigorously mixed
- the mixing caused the antigens to precipitate, which prevents the antigen/adjuvant from being rapidly dispersed and degraded throughout the body
- provides a persistent and localized stimulation of the immune response
- the mycobacteria can activate macrophages and dendritic cells
Most common adjuvant used and approved for use in human vaccines are…
Alum
- they are a form of aluminum hydroxide
MF59
- emulsion of squalene, oil, and water
The need for a vaccine and the demands placed on t change with the prevalence of the disease
- some vaccines can mutate and cause disease
- need for vaccine is greater than the risks
Resurgence of the disease is an outcome of the concerns of the safety (like seen in whooping cough of the 1970s)
- caused by Bordatella pertussis
- beginning of 20th century 2000 cases per million children suffered/died from whooping cough
- in 1940s the DPT vaccine was introduced
Herd Immunity
- when a vast majority of the population has immunity against a pathogen due to vaccination or previous infection
- there will be no epidemics and even the non-vaccinated individual will be protected
- however if herd immunity is lost, there could be epidemics
As fewer children were vaccinated for measles…
- the incident of infections increased
Vaccines have not yet been found for….
- many chronic pathogens
Genome sequencing of humans open up new avenues of vaccine design
- complete genome of many bacterial and viral pathogens are known by DNA sequencing
- manipulation of pathogens genes (recombinant DNA techniques) can produce an attenuated pathogen that is good is use as a vaccine (live-attenuated vaccine)
- the success of vaccines against chronic infections will depend critically on their ability to steer the CD4 T cell responses in way that are helpful
The inclusion of cytokines in vaccine might help to drive…
- immunity in the desired direction
Vaccine development faces greater __________ scrutiny than drug development
- public
- vaccine are different than most other drugs
Other drugs are given to people who are already sick and are grateful for any improvement in their condition; are given on a case by case basis based on the symptoms/disease of the individual
Vaccines are administered to ____________ individuals, often very young
- healthy
- parents might be more concerned about the adverse effect of vaccine than the benefit from the vaccine
- they are also given to the greater population as mandated by government laws
- the only situation which a vaccine’s benefit can truly be felt is when exposure is obvious, because other unvaccinated members of the local community are suffering and succumbing in numbers to the disease
Production of live-attenuated viral strains by recombinant DNA techniques
- if a viral gene that is necessary for virulence but not for growth or immunogenicity can be identified, this gene can be either mutated or deleted by using recombinant DNA techniques
- this procedure creates an avirulent (nonpathogenic) virus that can be used as a virulence gene are usually many, so that the virus cannot easily revert to the wild type
Effector functions of adaptive immunity begin to work only after…
- 4 days or more
In the long term, immunological memory enables the strength of the secondary response to far surpass the primary response
- periodt
