Why secodary dengue infection more virulent?

[sameeralord]

If u get infected with X serotype of dengue. And then you get infected again with Y serotype you get a severe infection. What is the exact pathology behind this. Also what happens if you get infected by X serotype again, do you get severe infection then as well. Thanks

 

[bobze]

Its thought the reason that reinfection with other serotypes of dengue is so bad is due to more massive cytokine release on the part of the host (humans in this case, I'm not sure how the monkeys that get dengue react to reinfections). So the DIC and other complications are mediated by a cytokine-stormish scenario.

After infection from one dengue serotype, supposing you don't get hemorrhagic fever and die, you should have immunity to that specific serotype--however it does not confer immunity to other serotypes and as mentioned above makes subsequent infections worse.

 

[sameeralord]

Thanks bobze

 

[Pyaemia4]

To add to the last post, the reason why subsequent infections with different serotypes can be much worse is due to the phenomenon of antibody-mediated enhancement.

As was already said, infection with one serotype will result in the production of antibodies that neutralize that specific serotype. If the same person then becomes infected with a different serotype, those antibodies will then bind to, but not neutralize the new virus. This antibody "coat" on the new virus actually allows it to more easily enter and infect new cells by interacting with antibody Fc receptors.

 

[fawley]

I think that the same goes for HIV, right? The enhancement of infection of the MT 2T-cell, specifically. I think there is some debate going about the sub-neutralizing effects of the vaccine given to volunteers in a study which might lead to a better immune response to HIV. This page here lists many of the antibodies used for these studies. I find it very useful. I personally find it very interesting how companies do progress in this field, but there is still much to be done to develop an effective vaccine.