Flashcards
CSIM1.29
Cards in this deck (50)
- 1Describe the Primary Humoral Immune responseAntigen presenting cells (dendritic cells) move from site of infection to T cell zone of lymph node
Antigen specific T cell activated by dendritic cell
Circulating B cells trapped at T cell zone border
Antigen specific B cell activated by same antigen specific T cell and starts to proliferate
B cell moves to B cell zone and forms primary follicle - 2Describes the bodies various effects to a specific antibody
- 3What is an antigen?A live or inactivated substance (e.g., protein, polysaccharide) capable of producing an immune response
- 4What is an antibody?Protein molecules (immunoglobulin) produced by B lymphocytes to help eliminate an antigen
- 5What is a vaccine?Antigenic preparation whose administration in a subject induces an immune response specific to the given infectious agent
- 6What are the 2 key elements of adaptive immunity?Specificity and memory
- 7What is passive immunity?Protection transferred from another person or animal as antibody
- 8How is passive immunity passed from mother to baby?Through maternal antibodies in the placenta or through breast milk
- 9How long does passive immunity last?Passive immunity only lasts for weeks or months. In the case of measles, mumps and rubella it may last up to one year in infants - hence MMR given just after first birthday
- 10How can we artificially give passive immunity?Administration of antibodies (immunoglobulin) collected from actively immune humans or animals e.g. varicella zoster immunoglobulin VZIG eg.
(Ebola virus-specific hyperimmune serum) - 11What are the main sources of passive immunity?Some blood products, homologous pooled human antibody (immune globulin), homologous human hyperimmune globulin (ZIG, Rh, anti-D), hetrologous hyperimmune serum (antitoxin- snake antivenom)
- 12What are monoclonal antibodies?Derived from a single type or clone, of antibody-producing cells (B cells)
Antibody is specific to a single antigen or closely related group of antigens
Used for diagnosis and therapy of certain cancers, autoimmune conditions, and infectious diseases - 13How does T cell passive immunity work?Transfer of (antigen) viral-specific T cells from a donor to a recipient to counter viral infection in the immunocompromised:
CMV
EBV
Adenovirus - 14How do we classify vaccines?Live attenuated: viral/ bacterial
Inactivated - 15What parts of an antigen may be given in an inactivated vaccine?Whole: virus, bacteria
Fractional: protein-based, subunit or toxoid, polysaccharide-based, pure or conjugate - 16What is a live Attenuated Vaccine?Attenuated (weakened) form of the "wild" virus or bacteria
Must replicate to be effective
Immune response similar to natural infection
Usually effective with one dose*
May get mild symptoms - 17give some examples of viral Live Attenuated VaccinesMeasels, mumps, rubella, vaccinaia, varicella, yellow fever, rotavirus
- 18Give an example of a bacterial Live Attenuated Vaccine?BCG
- 19Describe the effectiveness of inactivated vaccinesCannot replicate
Minimal interference from circulating antibody
Generally not as effective as live vaccines
Generally require 3-5 doses
Immune response mostly humoral
Antibody titer diminishes with time - 20Give some examples of whole cell viral vaccinespolio, hepatitis A, influenza, rabies, (Tick-borne encephalitis)
- 21What signals are required for Thymus Dependent B Cell Activation?100,000 membrane bound Ig B cell receptors (BCR)/cell membrane
1st signal – B cell receptor (membrane-bound-Ig) with ‘cognate’ antigen and ‘clustering’ of Ig receptors - 22What does clustering of Ig receptors allow?It enables many Iga and Igb molecules to associate with each other.
- 23What is thymus independent antigen?Ab response without mature T cells
Not MHC-dependent T cell help
Often CHO
Abs mainly IgM (& IgG2)
Poor class switching, no memory - 24What are the 1st and 2nd signals in the thymus independent antigen process?1st signal delivered by antigen-receptor interaction
2nd signal – through toll-like receptors or extensive BCR
cross-linking - 25What induce the T cell-independent responsePolysaccharide antigens
- 26Describe the binding of antigen to Thymus Independent Antigen - Type 1
- 27Describe the binding of antigen to Thymus Independent Antigen - Type 2
- 28What happend when there is a high concentration of TI-1 antigen?
- 29Describe TI-type 1 antigen?Intrinsic activity to directly induce B-cell division
low concentation – Ag specific
only activate Ag specific B cell - 30What response is caused by TI-2 antigens?and what response is followed by activated dendritic cells
- 31Describe Pure Polysaccharide VaccinesNot consistently immunogenic in children <2 years of age
No booster response
Antibody with less functional activity
Hyporesponsiveness ? Due to high density of Ag anergy
Immunogenicity improved by conjugation - 32What is a Conjugate Vaccine ?Polysaccharide antigen linked to a protein antigen e.g. Hib and Meningococcal conjugated vaccines
Designed to enhance immune response, particularly in children under 2 years old who do not respond well to non-conjugated polysaccharide vaccines - 33What are thymus independent antigens?When antigens are lacking the peptide componenet
- 34What happens when an antigen lacks the peptide component?It cannot be presented by the MHC to the T cells
- 35Give an example of thymus independent antigenLiposaccharide from the cell envelope of gram -ve bacteria and polysaccaride capsular antgens
- 36Why is recognition of thymus independent antigen important?It allows for antibodies to still be made
- 37Is there memory after antibody generation to a thymus independent antigen?No
- 38What are thymus dependent antigens?Antigens that contain an proten component
- 39What is immunological class switching?A biological mechanism that changes a B cell's production of immunoglobulin (antibodies) from one type to another, such as from the isotype IgM to the isotype IgG.
- 40What part of an antibody is changed during class switching?the constant-region portion of the antibody heavy chain is changed, but the variable region of the heavy chain stays the same
- 41Define AdjuvantTo enhance the immune response to the vaccine’s antigen
To carry the vaccine antigen and to slow its release
To provoke a local inflammatory response - 42Why was the HPV vaccine hard to develop?Can’t culture papillomavirus in lab
No reliable in vivo or in vitro source of intact papillomavirus - 43How does the HPV vaccine work?Virus like particles1
Recombinant vaccinia virus formed by insertion of HPV 16 L1 gene using plasmids
Virus like particles isolated from infected fibroblasts
Safe because they don’t contain the genetic material required to replicate - 44What rules should you follow before giving a vaccine?Consent
Expiry Date
Record Batch number
Correct route of administration
Resuscitation facilities - 45What contraindications are there to administering some vaccines?Acute febrile illness
Previous history of severe local or general reaction to previous dose
Live vaccine to pregnant women - 46What factors are NOT contraindications for giving vaccines?H of adverse reaction following immunisation
Previous history of pertussis, M, M or R infection
Prematurity
Stable neurological condition
Contact with infectious disease
Asthma, eczema, hay fever, ‘snuffles’
Treatment with antibiotics, local steroids - 47What local reactions can happen as a result of vaccination?Extensive area of redness & swelling which becomes indurated & involves most of antero-lateral surface of thigh or major part of circumference of arm
- 48What general reactions can happen after vaccination?Fever 39.5 C within 48 hrs of vaccine
Anaphylaxis
Bronchospasm
Laryngeal oedema
Generalised collapse
Prolonged unresponsiveness or inconsolable/high-pitched screaming
4 hours
Convulsions/encephalopathy within 72 hours - 49What are the properties of the ideal vaccine?Activate antigen presenting cells & cytokines
Activate T & B lymphocytes
Lots of memory
Generate Th & Tc cells to several epitopes
(to overcome variation due to MHC polymorphisms)
Antigen persistence - follicular dendritic cells - 50Describe the ideas behind a vaccine for HIVTricky!
Need DC to take up virus, activate + present on MHC I to induce CD8+ T cell response
‘Attenuated’ virus can cause disease in susceptible individuals
‘Attenuated’ virus may mutate – become virulent
High mutation rate of HIV means vaccine may be ineffective against the ‘many different HIV’ in any one individual
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- Flashcards on CSIM1.29, created by diseasel.medsoc on 04/05/2015.
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