First immuno response

Tuan Anh Tran tuant at taurus.oac.uci.edu
Wed May 13 03:46:36 EST 1998

On Fri, 8 May 1998, Trond Erik wrote:

> Sorry if this question has been recently debated...
> I've been wondering about this for a while. It seems like a version of
> the classic hen and egg.
> To be able to battle infections, plasma cells (active B-cells) secrets
> spesific antibodies. But for a B-cell to become active, it has to be
> stimulated by a helper-T-cell. And for a helper-T-cell to be active, it
> needs to be stimulated by an APC. An APC is a former makrofag who has
> ingested antigen/antibody-complexes, therby becoming an APC.

there is also a two cell model to the activation of the b-cell beside the
3 cell model that you are talking about, the model states that CD+4 T-cell
also have Ag receptors on there membrane that binds to MHC II Ag, the
T-cell binds to the Ag of the foreign object, which it process to be on
its surface,the T-cell differentiate into T-helper 2 cell which activates
the B-cell by various cytokine secretion,

> say it hasn't secreted antibodies yet. When the first infection arrives,
> how can it respond? It doesn't have the necesarry secreted antibodies to
> facilitate ingestion by makrofags. And that is the first step in humoral
> immuno response.

when the first infection arrive, it could either go thru the 3 cell model
like you stated or the 2 cell model to activate the B-cell to produce Ab,
also the Ab only neutralize the foreign substance (toxin, etc) macrophages
then come in for phagocytosis

 > > Regards
> Trond Erik Vee Aune

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