Immunity to parasites Flashcards
are the protozoan parasites intracellular or extracellular ?
they can be both
are the protozoans big or small in size ?
small
how is malaria transmitted ?
by the female anopheles mosquito
what is the natural resistance to malaria ?
sickle cell anemia
what does species specificity mean in malaria ?
so having immunity against 1 species does not protect against others
what does stage specificity mean in malaria ?
immunity against one life-cycle stage does not protect against another
malaria shows antigenic variation , what does this mean ?
the parasite changes it’s antigens to allow reinfection and evade killing
malaria shows immune suppression , what does this show a strong correlation with ?
Burkitt’s Lymphoma which is a cancer
what do you need to destroy to combat malaria ?
The parasite itself and
the immune cells or RBC infected with the pathogen
what in the immune system is involved in combating ?
CD4+ T cells - TH1 and Th2
Cd8+ cT cells - killer cells
Antibodies
what are our responses to the parasite controlled by ?
genetic and environmental factors
how is leishmania transmitted ?
by an infected sandfly
what is the promastigotes ?
the parasite inside the insect , the sandfly
what are the intracellular amastigotes ?
when the parasite enters the macrophages inside the human.
what do the APC , dendritic cells , produce and what does this result in ?
IL 12 which activates the macrophages to kill the intramacrophage parasite
what do the NK cells and TH1 cells release which help to combat the parasite ?
IFN gamma which also activates the macrophages
what do the activated macrophages release?
microbicidal products such as superoxide , nitric oxide which kill the parasite
how does leishmania evade detection ?
as it lives inside the macrophage it can turn off cell killing so the macrophages are no longer activated.
what is the definitive host for toxoplasma gondii ?
a cat
what does the host produce ?
oocyst
what can the oocysts infect ?
any host
what does the parasite live inside ?
cysts
what’s the main response to toxoplasma gondi ?
the CD8+ T cells that produce IFN gamma
IgA
IgG
what can occur to AIDS patients ?
the cysts in the brain can reactivate causing encephalitis
what does IgA do ?
they play a role in protecting the gut mucosa by neutralisation
how are the IgG coated parasites killed ?
inside the macrophage following the phagolysosome fusion
what is trypanosoma brucei also called ?
sleeping sickness
what’s the 2 stages called ?
a slender stage and a stumpy stage
where does the parasite live ?
in the bloodstream
is the parasite extracellular or intracellular ?
extracellular
what is used in the humoral response ?
antibodies
what produces the IgM antibody and how does this fight the infection?
the plasma B cell and this is directed against the variant surface glycoprotein
what is antigenic variation ?
this is when the surface coat changes it’s antigens
what is the Th1 response?
this is when IFN gamma is produced and this acts on the macrophage and reactive oxygen intermediates and reactive nitrogen intermediates are also released.
how often does the switch occur ?
every 100 divisions
what does trypanosoma Cruzi cause ?
the Chaga’s disease
is the parasite intracellular or extracellular ?
it can be both
what is the trypomastigote ?
this is the extracellular
what is the amastigote ?
this is the intracellular
what does the parasite infect ?
the macrophages which affects the muscles
how can this parasite lead to death?
the host can no longer swallow and the heart muscle can stop beating
what are the immune responses induced ?
the IFN gamma stimulates the macrophages and cytotoxic T cell kills the infected muscle cell
what is the theory around this parasite and autoimmunity?
is the antigen on the parasite so similar to our own cells that this causes autoimmunity?
what T cell prevents autoimmunity ?
the Treg cell
how does the body expel gut nematodes ?
They do so by increased mucus production and iincreased peristalsis, which is the movement in the gut.
