Conjugated vaccine.. immunology

[anbuitachi]

Hi, i'm pretty confused about how conjugated vaccine works... Uworld says it mainly stimulates B cell immunity with production of B memory cells, and not T cells. Can someone explain how this works..? Thanks!!

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[paul411]

Here's a good picture and accompanying explanation: http://www.nature.com/nri/journal/v9/n3/fig_tab/nri2494_F1.html

 

[anbuitachi]

Oh cool thanks. though how come it doesn't also have T cell mediated since it does activate the T cells [for the bottom picture]

 

[Transposony]

Hi, i'm pretty confused about how conjugated vaccine works... Uworld says it mainly stimulates B cell immunity with production of B memory cells, and not T cells. Can someone explain how this works..? Thanks!!

The conjugated vaccine produces immune response by recruiting type 2 helper T cells, which allow for immunoglobulin class switching (to produce non-IgM immunoglobulin) and production of memory B cells. A polysaccharides vaccine alone would lead to formation of IgM only as there can be no class switching in the absence of protein antigen (no protein antigen>no T-cell activation>no class switching AND no T-cell activation>no memory B-cells).

 

[anbuitachi]

The conjugated vaccine produces immune response by recruiting type 2 helper T cells, which allow for immunoglobulin class switching (to produce non-IgM immunoglobulin) and production of memory B cells. A polysaccharides vaccine alone would lead to formation of IgM only as there can be no class switching in the absence of protein antigen (no protein antigen>no T-cell activation>no class switching AND no T-cell activation>no memory B-cells).

Oh! thank you! that makes a lot of sense

 

[paul411]

A polysaccharides vaccine alone would lead to formation of IgM only as there can be no class switching in the absence of protein antigen (no protein antigen>no T-cell activation>no class switching AND no T-cell activation>no memory B-cells).

A side note: this used to be the classical understanding but is not entirely true. The pneumococcal polysaccharide vaccine (Pneumovax) induces an IgG response despite the lack of a protein component. [Source]

 

[moneill]

Re: Pneumovax....

I had to reply to this. I have Di George Syndrome absent thymus. Before vaccine they check IgG subsets I was missing 10. They give the vaccine and do measurments afterwards. I was missing IgG subsets afterwards. Then overtime they all had good levels.

The IgM was never even looked at. My kids as well were given pnumovax. As an adult you should have protective IgG levels notably my IgG 2 and 4 were low constant infections. After the vaccine some of our infections have decreased ear and sinuses.

Hope that helps.

 

[Etorphine]

The conjugated vaccine produces immune response by recruiting type 2 helper T cells, which allow for immunoglobulin class switching (to produce non-IgM immunoglobulin) and production of memory B cells. A polysaccharides vaccine alone would lead to formation of IgM only as there can be no class switching in the absence of protein antigen (no protein antigen>no T-cell activation>no class switching AND no T-cell activation>no memory B-cells).

Good explanation. Any body know if these conjugated vaccines can induce a T-cell memory response in addition to the memory B cells? If so, which type of memory T-cells are induced. (I could have sworn I had a UWorld question concerning this topic)

 

[Transposony]

Good explanation. Any body know if these conjugated vaccines can induce a T-cell memory response in addition to the memory B cells? If so, which type of memory T-cells are induced. (I could have sworn I had a UWorld question concerning this topic)

That would be cell mediated immunity mediated by Th1 cells (aka T helper type 1).

There are three types of T-cells involved: naive, memory and effector T cells.

Here is an excellent article from Nature.

 

[GunbydayJREbynt]

Good explanation. Any body know if these conjugated vaccines can induce a T-cell memory response in addition to the memory B cells? If so, which type of memory T-cells are induced. (I could have sworn I had a UWorld question concerning this topic)

I am also confused by this. Wouldn't the Tcell that helped the Bcell with this conjugate vaccine produce a memory Tcell response... but not to the polysaccharide. Rather, it would be a memory response to the protein conjugate.

While on the other hand, the B-cell endocytoses the whole molecule, chops it up, and is presenting the protein antigen to the Tcell (but it is programmed to make anti-polysaccharide Abs). So once it tricks the Tcell into giving it the activation it needs, it can produce anti-polysaccharide Abs and differentiate into memory Bcells against the polysaccharide???

Am I understanding this correctly???

 

[Etorphine]

That would be cell mediated immunity mediated by Th1 cells (aka T helper type 1).

There are three types of T-cells involved: naive, memory and effector T cells.

Here is an excellent article from Nature.

Excellent! Thank you very much.