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Posted

Hi,

 

I've a question about virology & immunology

This is my first post and I hope you help me to find out the answer

 

Q: How the viruse can be transmitted from the mother to the embryo since the mother has antibodies which can cross the placenta to the baby??

apply this qestion on the primary infection and on the reactivation (generaly and for cytomegalovirus)

Posted

Viruses are small enough to pass across the placenta and infect the fetus. It is true that antibodies are able to cross the placenta, but only specific ones (IgG1 and IgG3) and these take time to make in the mother after primary infection. This lag phase required to make IgG antibodies gives the virus sufficient time to infect and replicate in the embryo.

  • 2 months later...
  • 3 months later...
Posted
hello i want to about how to isolate HIV variants from blood

different variants????????/

 

You can't isolate HIV particles from the blood! HIV infects lymphocytes and stays in latents phase there.

The virus drops lyphocytes blood count and makes patients be sensitive to various pathogen infections.

Posted
Viruses are small enough to pass across the placenta and infect the fetus. It is true that antibodies are able to cross the placenta, but only specific ones (IgG1 and IgG3) and these take time to make in the mother after primary infection. This lag phase required to make IgG antibodies gives the virus sufficient time to infect and replicate in the embryo.

 

German measels (rubella) is a good example of this... It has a few weeks incubation period where no immue responce is made and it can infect a foetus with devastating consequences...

 

http://en.wikipedia.org/wiki/Congenital_rubella_syndrome

 

Btw, viruses are primarily delt with by the innate immune system (e.g. macrophages and neutrophils)... The anti-body responce via production of antibodies from b lymphocytes is important for protection against bacteria but not viruses... Foetuses definitely do have an immune system to provide protection against viruses and if you want to know more about the immunity of a foetus then look into the development of the bone marrow and the thymus gland...

 

There is good reason why antibodies don't cross the placenta... For example, where the mother has group A blood and the foetus has group B blood (thus you need to prevent the anti-B antibodies crossing the placenta)...

 

but this indeed does happen... The most common is Rhesus disease... This is haemolytic disease of the newborn caused by rhesus negative mothers giving birth to their second rhesus positive child due to anti-rhesus antibodies crossing the placenta...

 

http://en.wikipedia.org/wiki/Hemolytic_disease_of_the_newborn

Posted
The anti-body responce via production of antibodies from b lymphocytes is important for protection against bacteria but not viruses...

 

Truth is that antibodies are very important in both kinds of infections (bacterial and viral) especially in viral infection!

In bacterial infections we have antibiotics that kill the pathogen and antibodies only helps by opsonizing the bacteria.

In viral infection the antibodies neutralize the virus and prevent its spread to new cells. So the ''only'' thing that is left to immun system (NK cells, Tc cells etc.) is to eliminate already infected cells.

In emerging infectious diseases, like WN - fever, we use immunoglobulins to treat hard patients

Posted
Yes I know... but prescribed antibiotics specifically target bacteria and not viruses...

 

that's not what I said?!

 

''In bacterial infections we have antibiotics that kill the pathogen ...In viral infection the antibodies neutralize the virus and prevent its spread to new cells.''

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