Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!boulder!eddy
From: eddy@boulder.Colorado.EDU (Sean Eddy)
Newsgroups: sci.bio
Subject: Re: Who Has Immunity?
Message-ID: <7914@boulder.Colorado.EDU>
Date: 4 Apr 89 19:16:43 GMT
References: <2600@tank.uchicago.edu>
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<2600@tank.uchicago.edu> ogil@tank.uchicago.edu (Brian W. Ogilvie) writes:
>How far down in the animal kingdom is some type of immune system
>found? Do, say, mollusks have immune systems? What about annelids?

Ah, a question I've been interested in too.

Specific antibody responses seem to be limited to vertebrates.

Invertebrates do have phagocytic cells (cells that eat foreign
matter) and in at least some cases there seems to be an
ill-defined specificity for eating non-self antigens in preference
to self antigens (in sea urchins, for instance).

Graft rejection has been demonstrated in several invertebrate systems,
and in earthworms there are a few reports of immunological memory
w/ respect to graft rejection: grafts are rejected
markedly faster the second time they are seen.

I have heard rumors that some invertebrates may make small 
antibacterial peptide antibiotics, of broad specificity.
I dimly recall hearing something similar about plants.

Molecular biology-wise, two genes that belong to the immunoglobulin
superfamily (which includes antibody genes, T-cell receptor genes,
and various other cell surface protein genes) have been found in
invertebrates that I know of -- one in Drosophila and one in
grasshoppers. In both cases they're probably functioning as
something besides immune system components, though.

Why do you ask?

- Sean Eddy
- Molecular/Cellular/Developmental Biology; U. of Colorado at Boulder
- eddy@boulder.colorado.EDU		!{hao,nbires}!boulder!eddy