ogil@tank.uchicago.edu (Brian W. Ogilvie) (04/05/89)
This is a question for any immunologist types out there: How far down in the animal kingdom is some type of immune system found? Do, say, mollusks have immune systems? What about annelids? Also, do plants have any immune system? I don't mean something like restriction enzymes in bacteria (which could be construed as a basic, antiviral immune system: I'm looking for specific responses to antigens. Thanks for your time.
eddy@boulder.Colorado.EDU (Sean Eddy) (04/05/89)
<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
dd@beta.lanl.gov (Dan Davison) (04/05/89)
In article <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? Frogs have recently been found to have Ig-type molecules, but I don't recall the details. At least 2 years ago in a Nature News & Views article someone said that the self/non-self MHC/HLA (Major Histocompatibility Locus (mouse) and Human Leucocyte Antigen (human) ) existed in sponges. I think the reference was "MHC-like". I have since looked for the reference but haven't found it. dan davison/theoretical biology/t-10 ms k710/los alamos national laboratory los alamos, nm 875545/dd@lanl.gov (arpa)/dd@lanl.uucp(new)/..cmcl2!lanl!dd "...the wise man is one who never sets himself apart from living things..." Le Guin, _The Farthest Shore_
pell@boulder.Colorado.EDU (Anthony Pelletier) (04/05/89)
(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? > (Sean Eddy) writes: >Specific antibody responses seem to be limited to vertebrates. > >I have heard rumors that some invertebrates may make small >antibacterial peptide antibiotics, of broad specificity. >I dimly recall hearing something similar about plants. > >- Sean Eddy >- eddy@boulder.colorado.EDU !{hao,nbires}!boulder!eddy Actually, Sean, plants have a rather effective way of dealing with pathogens, seeing as they are notably inefficient at running away. you could have asked...not that I am bothered by your "dim rumors." (+: just kidding buddy) None of the methods are exactly like an "immune system," per sey, so I won't go into too much detail. But one rather cute one worked at this universtiy a while back was the "hypersensitive response." It seems that there are ani-fungal and anti-bacterial polysacharides in the cell wall of plants, as well as things cyto-toxic to the plant cell *itself*. In the process of trying to chew its way into the cell, the pathogen releases these agents from the cell wall and is those the agent of its own distruction. The plant cells surrounding the invasion also die, to remove available hosts for surviving pathogens. As an aside, those more succesful pathogens usually get in by secreating auxin and cytokinin-like peptides and thereby induce an ingrowth in the cell wall (the "infection thread" or "infection tube"). So they don't actually destroy any plant tissue until they are inside (symbionts such as rhizobia use this method too). -tony