vaccines and immunological response Flashcards
cytotoxins
a cytotoxin has a direct toxic and destructive effect on certain cells of the body
cytotoxicity
the quality of being toxic to cells
endotoxin
toxins present inside a bacterial cell that is released when it disintegrates
what cause production of cytokines
endotoxins
cytokines
caused by the release of endotoxins upon binding to immune cells
examples of cytokines
interferon, interleukin and growth factors- any substance which are released by certain cells of the immune system and have an effect on other cells
two main antibodies of the adaptive immune response
IgG and IgM
IgG
- made up of 4 polypeptide chains
- 2 heavy chains (50kDa)
- 2 light chains (25kDa)
IgM
can be circulating as a pentameter or on the surface of B cells
two parts of the immune system which prevents infection
innate immunity and adaptive immunity
innate immunity
-non-specific and general. Immediate response.
NO IMMUNOLOGICAL MEMORY
two parts of innate immunity
1) humoral: complement, enzymes, cytokines
2) cellular: phagocytes, natural killer cells and pattern receptors
humoral- innate
complement, enzymes, cytokines
cellular-innate
phagocytes, natural killer cells and pattern receptors
adaptive immunity
- specific to antigen
- lag time form exposure to response
- immunological memory
2 parts of the adaptive response
1) humoral: antibodies and cytokines
2) cellular: T cells and B cells
humoral- adaptive
antibodies and cytokines
cellular- adaptive
t cells and b cells
immunological cells all come from
bone marrow stem cell
innate cells come from
myeloid precursors
monocytes
dendrite cells and macrophages
granulocytes
neutrophils and mast cells
adaptive cells come from
lymphoid precurosors
bone marry maturation
B cells –> plasma cells
thymus maturation
T cells
light chain of antibodies found
on the outside
heavy chain of antibody found
on the inside
primary response is made up mostly of
IgM
secondary response is made up mostly of
IgG
IgA
found in mucous, saliva, tears and breast milk–> protects against pathogens
-x2 antibodies
IgD
part of the B cell receptor. activates basophils and mast cells
IgE
protects against parasitic worms. responsible for allergic reaction
IgG
secreted by plasma cells into the blood. Able to cross the placenta into the fetus
IgM
may be attached to the surface of B cells or secreted into the blood. Responsible for early stages of immunity
–> PENTAMER
antibodies
recognising foreign pathogens and opsonising them. This aids in their uptake by Fc receptors on phagocytes, leading ton their eventual destruction
opsonisation
tells immune cells which pathogens to take up
what to antibodies on pathogens attach t on immune cells
Fc receptors
T cells
required for protection against intracellular pathogens
process of cytotoxic R cells and destruction of infected cell
1) cytotoxic T cell binds to infected cell
2) perforin from T cell makes hole sin infected cells membrane
3) infected cell lyses
cytotoxic T cells
protect against intracellular pathogens
what protects against extracellular pathogen sand toxins
antibodies
types of vaccine
toxoid, live and attenuated, subunit, conjugates, inactivated, DNA, recombinant vector
vaccines provide the
primary response- therefor the next time that individuals comes into contact with that pathogen, the response is massive and they will not become unwell
subunit vaccines
can contain anywhere from 1 to 20 antigens. Pathogens are grown and then chemicals ar used to break it apart and important antigens are gathered. These antigens can then be used in recombinant DNA technology
subunit vaccine process
- -> gene from bacteria added to plasmid using recombinant technology
1) lac promotor with IPTG added and causes transcription of the T7 RNA polymerase.
2) this will then attached to the correct site on the plasmid with the cloned gene
3) T7 RNA polymerase then transcribes the clone gene and the gene product (protein) is produced
positives and negative of using E.Coli as a recombinant host
+ve: well developed genetics, many strains, best known bacterium
-ve: potentially pathogenic. periplasm traps proteins
positives and negative of using Bacillus subtilise as a recombinant host
+ve: easily transformed, nonpathogenic, naturally secrets proteins, endospore formation simplifies culture
-ve: genetically unstable, genetics less developed than in E.coli
positives and negative of using Eukaryote Saccharomyces cerevisiaeas a recombinant host
+ve: well developed genetics, nonpathogenic, can process mRNA and proteins, easy to grow
-ve: plasmids unstable and will not replicated most bacterial plasmids
problem with live attenuated vaccines
with identifying which genes to knockout if no obvious virulence factors. Good targets are those involved in amino acid metabolism
what is used in KO (knockout) in live attenuated vaccine production
homologous recombination–> knockouts of certain genes, making them safe to be used as vaccines
example of phenotypes of KO pathogens
A C.difficile bacteria KO’s for a cell surface antigen can no longer adhere to gut cell
