How does the immunological response differ upon re exposure to a pathogen that one is vaccinated against....mainly i want to know what is the different type of response ellucidated by a killed vaccine vs. attenuated vaccine upon re exposure to the pathogen?
Can someone please explain how the immunological response differs upon reinfect?
- Thread starter alisepeep
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Shot in the dark, I might be making stuff up...because I'm not quite sure what you're asking.
But if you're vaccinated against something [successfully], then you have the antibodies. If you are re-exposed then I don't believe anything should happen because you are now immune. Antigen will be neutralized or whatever.
...unless it's Denge hemorrhagic fever.
But are you asking the difference between live attenuated and killed? Live attenuated has the risk of reactivation and causing a response, so it's not used against the elderly (I think) or immunocompromised (definitely, but FA p.181 [2012] says MMR is okay for those who are HIV+ without signs of immunodeficiency). Also live attenuated is better for inducing humoral and cell mediated immunity while killed is usually just humoral.
......................................................... I think. :-/
But if you're vaccinated against something [successfully], then you have the antibodies. If you are re-exposed then I don't believe anything should happen because you are now immune. Antigen will be neutralized or whatever.
...unless it's Denge hemorrhagic fever.
But are you asking the difference between live attenuated and killed? Live attenuated has the risk of reactivation and causing a response, so it's not used against the elderly (I think) or immunocompromised (definitely, but FA p.181 [2012] says MMR is okay for those who are HIV+ without signs of immunodeficiency). Also live attenuated is better for inducing humoral and cell mediated immunity while killed is usually just humoral.
......................................................... I think. :-/
Hmm thats kind of what im asking but i wanted more of the Tcell Be cell specifics...so for example lets say you a) received a killed Haemophilus vaccine a year ago..and you are now exposed to HaemB...how does your immune system respond in this case...vs... b) you receive a attenuated vaccine say against measles..you then come in contact with the measles virus..how does your body respond?
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First Exposure:
Local Site of infection:
Dendritic cells (langerhans cells) capture antigen
i. Lose tissue adhesiveness
ii. Up regulate CCR7
Chemokines CCL21 and CCL19 (SLC and ELC respectively) are secreted from the paracortex region of lymph nodes. Bind CCR7, these attract the cells to migrate into the paracortex region of the lymph nodes.
iii. on their way to lymph node up regulate B7
iv. Also process antigen via cross presentation: basically upregulate MHC1 and MHC2 and present w/e antigen it was onto both receptors!
*Note: only dendritic cells can activate naïve T cells!
*Note: only dendritic cells can process "extracellular antigens" via the MHC1 pathway via cross presentation. (otherwise you couldn't activate CTLs!)
*Note: dendritic cells arrive via the afferent lymphatics. Naïve T cells and B cells also have CCR7 but reach the paracortex region via the high endothelial venules from the blood supply.
Once in the paracortex they stimulate CD4+ and CD8+ to proliferate, as well as differentiate into effector cells and memory cells.
Blah blah, the cell mediated response etc. Creation of antibodies etc.
2nd exposure is a faster response because memory T cells and some antibodies are already circulating, and don't first have to be activated to proliferate/differentiate. They directly responed to the antigen presentation at the local site of infection.
I had a lot more to say/there is more detail, but I figure its too low yield/im already bored -.- haha
Local Site of infection:
Dendritic cells (langerhans cells) capture antigen
i. Lose tissue adhesiveness
ii. Up regulate CCR7
Chemokines CCL21 and CCL19 (SLC and ELC respectively) are secreted from the paracortex region of lymph nodes. Bind CCR7, these attract the cells to migrate into the paracortex region of the lymph nodes.
iii. on their way to lymph node up regulate B7
iv. Also process antigen via cross presentation: basically upregulate MHC1 and MHC2 and present w/e antigen it was onto both receptors!
*Note: only dendritic cells can activate naïve T cells!
*Note: only dendritic cells can process "extracellular antigens" via the MHC1 pathway via cross presentation. (otherwise you couldn't activate CTLs!)
*Note: dendritic cells arrive via the afferent lymphatics. Naïve T cells and B cells also have CCR7 but reach the paracortex region via the high endothelial venules from the blood supply.
Once in the paracortex they stimulate CD4+ and CD8+ to proliferate, as well as differentiate into effector cells and memory cells.
Blah blah, the cell mediated response etc. Creation of antibodies etc.
2nd exposure is a faster response because memory T cells and some antibodies are already circulating, and don't first have to be activated to proliferate/differentiate. They directly responed to the antigen presentation at the local site of infection.
I had a lot more to say/there is more detail, but I figure its too low yield/im already bored -.- haha
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Ok, I'll try.
Think about what attenuated vs. killed vaccines literally are.
Attentuated: bug actively infects target cell. All cells carry MHC1, right? Well, those bug proteins made in the cells are chopped up and displayed on MHC1 receptors. This causes the cytotoxic response, you have CD 8+ T cells that remember this.
At the same time, APC's present MHC2 to helper T cells and then we also have B cells make new antibodies.
Killed: cells do not become infected. you shoot a bunch of random peptides into someone. Only the humoral response is made.
The big difference is going to be that attenuated is always going to be better. Because you have having the body fight the real deal, you are creating better immunoglobins. Also, you have the memory T8+ response waiting for the next infection.
Most memory t cells, the ones that stick around for years and wait for the next infection, are made from CD8+ T cells. You don't get those in killed vaccines. http://en.wikipedia.org/wiki/Memory_T_cell
This is one of the reasons you need boosters for killed vaccines. You need to keep having B cells tested and thus making new libraries of immunoglobins, hoping to eventually give some kind of lasting immunity because in general the antibodies from killed vaccines have less antigenic variation and also you are missing one whole half, and very important part of the immune response.
Think about what attenuated vs. killed vaccines literally are.
Attentuated: bug actively infects target cell. All cells carry MHC1, right? Well, those bug proteins made in the cells are chopped up and displayed on MHC1 receptors. This causes the cytotoxic response, you have CD 8+ T cells that remember this.
At the same time, APC's present MHC2 to helper T cells and then we also have B cells make new antibodies.
Killed: cells do not become infected. you shoot a bunch of random peptides into someone. Only the humoral response is made.
The big difference is going to be that attenuated is always going to be better. Because you have having the body fight the real deal, you are creating better immunoglobins. Also, you have the memory T8+ response waiting for the next infection.
Most memory t cells, the ones that stick around for years and wait for the next infection, are made from CD8+ T cells. You don't get those in killed vaccines. http://en.wikipedia.org/wiki/Memory_T_cell
This is one of the reasons you need boosters for killed vaccines. You need to keep having B cells tested and thus making new libraries of immunoglobins, hoping to eventually give some kind of lasting immunity because in general the antibodies from killed vaccines have less antigenic variation and also you are missing one whole half, and very important part of the immune response.
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The response should inherently be the same, however as above mentioned, patient didn't get the whole exposure with the killed so they may respond only to some haptens/factors. Its like reading about something vs experiencing it. The body responds to pathogens in ways that we have yet to understand.
