Innate immunity

Mike Clark mrc7 at
Mon Feb 17 09:57:41 EST 2003

In article <o464a.961$mZ2.234059 at>, Geronimo
<URL:mailto:user at> wrote:
> I would also say your question is very interesting, thought for a
> different reason. I agree with Mike that AB-based immune responses fall,
> by definition, in the 'adaptive' class. I don't think there is ever an
> 'adaptive' response without an 'innate' response as well.
> The ABO antigen example highlights one of the many inconsistencies in
> Immunology. Although one could argue that anti-ABO ABs are expressed for
> some reason in every individual, the current paradigm cannot explain why,
> in case of a blood transfusion with an incompatible blood type, the
> immune response has the characteristics of a secondary rather than a
> primary response. Unless the same antigens are present in some very
> common pathogens, but that remains to be shown.

What of pregnancy?

A comparison of the immune response to RhD and to ABO mismatches shows that
the former can be a problem during pregnancy whilst the latter normally is
not. The observation is that the the immune response to RhD exhibits
affinity maturation and class switching to IgG, which can then cross the
placenta, whilst the anti-A and B responses remain as low affinity IgM.

So I don't regard the immune response to ABO as exhibiting a secondary type
immune response. The titres of antibody to A and B remain pretty much
constant throughout life which is why I am happy to view them as sharing
properties with components of the innate immune system such as Mannose
Binding Protein.

Mike                             <URL:>
M.R. Clark, PhD. Division of Immunology
Cambridge University, Dept. Pathology
Tennis Court Rd., Cambridge CB2 1QP
Tel.+44 1223 333705  Fax.+44 1223 333875

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