erythroblastosis fetalis

[Dr.Stein]

What is the mechanism for IgG to get into the fetus?
Probably it is forced into the blood of fetus though the fenistrations in the maternal capillaries , so the size , shape and molecular wt. all matter.

M I RIGHT???

hrushikesh

From a bleeding during the delivery. So far it was stated that IgG come into fetus via maternal-fetal circulatory system and it was not true.

[MrMistery]

From what i know IgG do come into the fetus via the circulatory sistem... That is the reason why the child dies in the first part of pregnancy. If what you say were true, the child would live.
It is true that blood cells do get inside the body of the mother at the first baby via bleeding during delivery

[victor]

Hey, I've read that beside IgG that comes to the fetus, There's also IgM which can be activated if there's any antigen infection.

[Dr.Stein]

From what i know IgG do come into the fetus via the circulatory sistem... That is the reason why the child dies in the first part of pregnancy. If what you say were true, the child would live.
It is true that blood cells do get inside the body of the mother at the first baby via bleeding during delivery

In erythroblastosis foetalis, the first baby is usually safe and live, because first, the contact with IgG will be happened just right when it has just been delivered. Second, the level of that IgG is just in a little number. In the second and subsequent pregnancy the level will increase and yes it will pass through placenta.

victor: IgM is the 'ancient' immunoglubulin family. All that fetus has is IgM. In the development, further exposure to antigens, it will switch into IgG, IgE, or IgA depends on the purpose. IgM also appears in acute disease, after few hours or days it will switch into, mostly IgG. The clinical examination of IgM and IgG can be used to determine whether the patient is still in acute phase or chronic phase of her/his disease, respectively.

[victor]

Hmm...it's just like IgM is the master of all Igs...(maybe because of it's pentamer valency 10 structure)

[Dr.Stein]

It is NOT a master, it is just an initial, an ancient type. IgM cannot do anything if it doesn't switched into proper IgG, IgE, or IgA. Those three types are more professional on their own purpose.

[iri_black]

IgE act as the fast response allergic because it's contained in basophyll
.

Related to the IgE activity, why some people are more sensitive to alergens than other? Does this have to do whith the quantity or the activity of basophylls.
Some allergies can be kept under control with certain vaccins. Does anyone know if theis vaccins contain IgE?

[Dr.Stein]

I am not sure IgE is contained in basophil. Immunoglobulins are produced by B cells...

[iri_black]

Ok, sorry about that .
But can you answer my question? Why some people are more sensitive to allergens?

[victor]

I am not sure IgE is contained in basophil. Immunoglobulins are produced by B cells...

Maybe produced by B-cells but complexed with basophils membrane.
Oh, yes, IgM also can be switched into IgD....so, that's why immature B-cells contain many IgM....because they're still not a professionals yet..

[Dr.Stein]

Naah, IgD never exists alone, and it's not a switched version from IgM, IgD always present with IgM, because there is no switching point from IgM to IgD.

This is a simple schematic of the switching points:

---IgM---IgD---*---IgG---*---IgA---*---IgE---

* = switching point

IgM/D -/-> IgD
IgM/D ---> IgG
IgM/D ---> IgA
IgM/D ---> IgE

[Dr.Stein]

victor: IgE is produced by plasma cell and being attached to cells which have a receptor for it, called FCεRI, such as mast cells, basophils, eosinophils

Ok, sorry about that .
But can you answer my question? Why some people are more sensitive to allergens?

Allergens actually are harmless antigens (innocuous), e.g. pollens, clothes, chitin, etc, but to certain people, they become harmful and even deadly things. Allergic reactions occur when an individual produces IgE in response to such innocuous antigen(s), and subsequently encounters the same allergen(s). Their 'sensitive' IgE, which mainly attach on mast cells membrane surfaces, recognize those antigens and then stimulate mast cells activation and degranulation.