Encapsulated Bacteria! - glitterflash

[ArchivalUser]

So I know that encapsulated bacteria are cleared by spleen after opsonization. My question is that, can IgG be produced against encapsulated bacteria?

[ArchivalUser]

Yes, which explains why patients with Brutons Agamma with no antibodies are at risk of severe infections with encapsulated bacteria because no IgG for opsonization, etc. immuno super HY, know everything in FA cold.

[ArchivalUser]

Thanks @pseudomyxoma
So here is the real question that has been annoying me a lot. IgGs can only be produced by the bcells once they have undergone class switching through a thymus dependent mechanism.
But the capsular polysaccharide has no protein attached and can only result into thymus independent activation of bcells, producing increased igM but no IgG.

[ArchivalUser]

i just read what i wrote and i apologize, IgG not made against encapsulated bacteria for the reason you mentioned.

[ArchivalUser]

So for opsonization of encapsulated bugs only C3b will be present in the picture? Since igM can activate the classic pathway.

[ArchivalUser]

and thanks for the help @pseudomyxoma, all your posts here are very helpful.

[ArchivalUser]

Exactly correct. And problem with Brutons is that no igM, no complement activation --> no C3b --> no opsonization so predisposition to severe infxns by encapsulated bacteria.

Thanks buddy, happy to help out.