The mammalian immune system appears to be the most complex of all known animal and plant immune systems. In fact, invertebrates do not possess in general most aspects and the adaptive immune system. Some creatures like fish possess some antibodies but not the full repertoire of antibodies and other factors found in mammalian systems....thus fish appear to possess a "transitional" immune system.
Mammals and humans require the adaptive immune system for survival. And even though invertebrates don't appear to require the adaptive system for survival they do display some immune responses consistent with the adaptive immune response...i.e, rejection of transplanted tissue. More recently, jawless fish do display lymphocyte type cells, consistent with an adaptive system. Is this evidence of an intermediate system?
Discuss the evolution and design aspects of the immune systems found in plants, invertebrates, mammals and fish. Do fish really possess a "transitional" immune system? Do any truly "intermediate" adaptive immune systems exist? Do you see design features inherent in the invertebrate immune system which appears to function without an adaptive system?
DUE Sept 26
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ReplyDeleteIt is safe to say that the immune system is pretty complex and it is essential for the survival of every living thing. How organisms identify and defend themselves does appear to build up to what mammals have today although each has its own tweaks and uniqueness. The smallest amoebas identify themselves from its food which it engulfs like a macrophage. Bacteria use “restriction endonucleases, antimicrobial peptidases, and RNA interference” to protect themselves” and their DNA just like our own cells do (http://ocw.mit.edu/courses/biology/7-345-evolution-of-the-immune-system-spring-2005/syllabus/).
ReplyDeleteThen, there are the more multi-celled organisms that possess a bigger arsenal of defensive mechanisms. At the very basic level, all organisms have some kind of innate immune system although each seems to have it’s unique touch. Plants for example have a two branched-immobile defense system (cells don’t move). Jawed fish and onward have more sophisticated, adaptive immune responses. Most attribute this to an immunological “big bang,” possibly caused by a transposable element. Many sources are aware that there seems to be a divide between innate and adaptive immune systems that takes place around the jawless invertebrates such as the hagfish and lampreys (http://www.ncbi.nlm.nih.gov/books/NBK27108/) thus causing them to be an example of an “intermediate” immune system.
Recent research has unveiled that the hagfish and lampreys in fact do have something similar to the adaptive immune system (with T and B-like cells) although it is very different (maybe this is why it took so long to discover it) from mammals. This alternative system consists of what are called variable lymphocyte receptors (VLRs) that are leucine-rich and are used, just like the mammalian adaptive, to recognize foreign antigens (http://www.pnas.org/content/early/2013/08/21/1314540110.short).
Evolutionists claim that this shows just another way in which the jawless fishes evolved after it split off from the phylogenic trunk, to hurdle a common problem which mammals later hurdled by making a similar defense mechanism (known as the adaptive mechanism today).
Lampreys have a similar response as that of an adaptive immune system, its different from a mammalian immune system structure.
DeleteThe discovery of Jaw-less fish having lymphocyte receptors was a break through discovery of jaw-less fish having an adaptive immune system. There are lot's of uncertainty on when the lamprey's immune system came to be and where it came from in terms of similarities in other species. Despite these critical questions that can't be answered, the Jaw-less fish seem to able to generate a lot of diversity using the technique of rearranging DNA. This is not full proof of an intermediate system, but it is certainly a possibility.
ReplyDeletehttp://www.sciencemag.org/content/310/5756/1892.2.full
A transitional immune system would be able to overlap innate and adaptive systems. It's hard to say if Jaw-less fish have a true transitional system, it seems that lampreys favor toward the adaptive system. Instead of destroying invaders as most innate immune systems work, the Jaw-less fish adapt to infection.
http://www.ncbi.nlm.nih.gov/pubmed/11378477
In opposition to what evolutionists defend, which is the connection between beings through an evolutionary tree full of branches and differentiation of species, I believe that each organism was created with its unique complexity in metabolism, whether if it’s in its way to protect, to obtain food, to excrete substances or to defend its ‘body’ from invaders.
ReplyDeleteScientists have mistaken while given more credit to what seems to be bigger and complex. Complexity is relative and there's no way we can state that phagocytosis done by a unicellular organism is a complex in “machinery” and in function than our (humans) immune system. Both are complex and depended on a Great Creator and Designer to surge.
The recent discover on jawless fish's immune system (i.e, lampreys) is giving to evolutionists a hard time, since it's complexity doesn't fit in their line of evolution. Lampreys appear to have a lymphocyte receptors, which brings its immune system close to a mammal immune system (adaptive). Evolutionary scientists try to explain this fact by arguing that lampreys developed this kind of ‘complexity’ in their immune system, starting a new branch in the evolutionary tree. However, the best explanation for the uniqueness in each organisms system is shown by the fact that God created each organism on its own complexity.
I agree with Lucas, the complexity of the lamprey's adaptive immune system speaks of a designer. Evolutionists may label this as a transitional form, but it could be compromised of its own unique immune system that is not an inbetween form, but rather its own form which is still not well understood yet.
DeleteMichael Behe, in his book Darwin's Black Box (Behe 1996 ) quotes, "An irreducibly complex system cannot be produced directly (that is, by continuously improving the initial function, which continues to work by the same mechanism) by slight, successive modifications of a precursor system, because any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional. An irreducibly complex biological system, if there is such a thing, would be a powerful challenge to Darwinian evolution. Since natural selection can only choose systems that are already working, then if a biological system cannot be produced gradually it would have to arise as an integrated unit, in one fell swoop, for natural selection to have anything to act on."
ReplyDeleteI feel that this is an interesting quote because it suggests that each creatures immune system was specifically and functionally designed (rather than evolved). Though we do not know the effects the fall might have had on God's original design, we know that He did not make an error or forget to give invertebrates adaptive immunity. Could it be that they were given innate immunity to prevent autoimmune disease? The innate system is much less specific, less diverse and limited compared to the adaptive immune system. However, invertebrates were still given an innate immune system to defend themselves from harmful pathogen... this system is just a less sensitive one.
-jLo
Jess, I think this is a really interesting quote too. I think it gets directly to the point of the issue. How can different invertebrate systems have an "intermediate" system? That would mean, like this quote is saying, that a functional part is missing. How could these fish or invertebrates have such a functional immune system now if it is not up to par? If our immune system is to be at the top of the evolutionary advancement, then why haven't these system changed over the years too or why are they surviving so well, if a complex innate and adaptive immune system is the best? As you said, it really shows that these immune systems in other animals are a full specific design, not a halfway system.
DeleteThe immune system of Jawless fish recently discovered is very complex. These variable lymphocyte receptors (VLRs) are composed of leucine-rich repeat (LRR) and are incredibly diverse as the genes that code for this immunity can be combined in various combinations creating incredible diversity. The cell can select and choose from its DNA to create an endless variety of receptors. Some evolutionists will claim this is an independent aspect of evolution that developed apart from jawed fishes immune systems or that it is the beginning of the creation of the immune system as it is ‘perfected’ further down the chain.
ReplyDeleteHowever, I believe that as more research is done we will discover that this immune system, as with other classes of organisms, that each are specifically unique. In evolution different aspects do not evolve apart from one another but rather characteristics and traits are passed down and perfected. This simply does not appear to be the case with these jawless fish. Rather the complexity and also divergence in assumed lineage claim something other than an evolutionary process and more likely a common designer with incredulous creativity.
The temptation of advocating a theory, or working towards its acceptance, is elevating it to fact before it is shown to be so, or in spite of evidence to the contrary. This fallacy can occur in every realm of intelligent frameworks – philosophy, science, theology, history, etc. Once one conceives an idea, seemingly so brilliant as to be irrefutable, it is easy to accept it entirely without question. So it is today, that discoveries, such as the adaptive-like immune system in jawless fish, are exciting to evolutionists, as they quickly call upon it to show a “transitional” system. It is the age-old problem of objectivity, most difficult to attain (some posture, impossible).
ReplyDeleteTruly, however, it makes sense that all organisms would have an immune system designed within them. Some are simple, reasonably so, as bacteria’s which lead rather “simple” lives (in that they are not multicellular, nor possess thought or instinct; yet the processes carried out within them are still immensely complex and detailed). Others, such as in humans and mammals on the whole, are more “complex” have more intricate systems. Yet, both serve the purpose they were designed for – each protecting the organism they are a part of. So the system found in jawless-fish (generation of diverse proteins called variable lymphocyte receptors (VLRs) with leucine-rich segments that often bind to other molecules) is, perhaps for unknown reasons as of yet, perfectly suited for the organisms it is a part of (jawless fish). - T.A.
I agree with Tirza that it is difficult to label these findings "evolutionary" as it cannot be reproduced or proven. How are we to know that this was not the original design for these creatures? Maybe we did not see it before, but now that there is a need for it, the system has been activated.
Delete-jLo
This has certainly been noted before by creationists in regards to the idea of design being seen everywhere in creation, rather than evolved survival techniques – that is, that a good design is properly used over and again. Thus, the system of fighting infection by generating a wide range VLRs (lymphocyte-like) be “mutating” or “mixing” the DNA sequences up randomly is effective in binding to the wide range of ligands on antigens. This system allows the immune system to recognize many antigens, rather than letting things slip by because the system had to receptor for that ligand to bind to.
ReplyDeleteJawless fish are considered, by evolutionists, to be a “lower” species than say sharks, osteichthyes and mammals, but this is based on the assumption of evolution as the process of developing species. Thus, if mammals are the most highly developed (particularly humans), and they have a bony-endoskeleton, then that system must be the most highly evolved. Thus, bony fish are more highly evolved than lampreys, and on down the line. However, if organisms were created by God, all kinds already present, and merely diversified, there is no reason to view jawless fish as “more simple” and therefore not surprising to find an adaptive-like immune system in them. Rather, research ought to be done regarding why both mammals and jawless fish contain this system – what similarities exist, what common functions or response must be carried out? In answering these questions, would then be able to further and better answer the questions – why did God create an immune system in a perfect world? - T.A.
According to Jeremy Bergman and Nancy O’Sullivan, it has been known for about fifty years that adaptive immunity is verifiable in cartilaginous fish. Experiments have found that the immune system in ancient vertebrates with jaws is quite compatible to with more recent mammals. Fish construct their gene segments to build genes for antigen receptors for T and B-lymphocytes. More recent research is reported to indicate that lampreys and hagfish have the ability to generate adaptive immune responses. Based on the research I have been able to find, a transitional immune system in fish seems highly unlikely. The immune systems found in life forms appear to have at least two characteristics in common, irreducible complexity and vast diversity. So the likelihood of one adaptive immune system being shared with or evolving into another form for a varying species seems improbable.
ReplyDeleteAn intermediate immune system implies that a lesser form needed to be altered and evolve into a more complex and sophisticated form. Since fish have the capacity to generate adaptive immune systems, why would an intermediate system be necessary? If primitive fish could generate immune systems then the immune system they possessed must have been sophisticated. Further research has shown the ancient immune systems were highly functional and complex. There doesn’t seem to be sufficient evidence for or a valid reason why intermediates would have existed.
-Jon M.
Lamprey’s have been found to have cells that function similarly to T-cells and B-cells. These cells have variable lymphocyte receptors (VLR) that act similar to antibodies on these cells. Their structure is considerably different than that of mammalian antibodies. Researchers have encoded three different types of receptors VLR-A, VLR-B, and VLR-C. The T-cell type produces VLR-A protein and the B-cell type produces VLR-B. Interestingly VLR-C is not comparable to the mammalian system and is the dominant white blood cell type on Lamprey’s, especially in larvae development. This can be seen as an intermediary system showing part of the “good” system of T-cells and B-cells and the “bad” which is the VLR-C type which is “taken out” of the evolutionary line. This direction of thinking does not seem to show what is truly going on in the system though. This system seems designed for a purpose for this animal. Firstly, as Tirza mentioned, if this were an evolutionary model of an intermediate immunological system, then shouldn’t this be seen in a more “advanced” animal? Secondly, the VLR is not similar structurally to antibodies. From what we know of the immunological system, the structure is a main reason the adaptive system works so well. The way it forms to recognize antigens is a crucial step. If this were an intermediary system, where is the intermediary for antibody? The mutation would have had to majorly change the whole structure to convert into a human antibody. Thirdly, this system was only thought about in terms of preventing foreigners. Why would VLR-C be so abundant in larvae? Partly could be the fact that they are developing and that they are in a fragile state, more open to foreigners. But why would it be VLR-C and not VLR-A or VLR-B? It seems this system relies more on this third receptor. Maybe this plays a dual role in the animal. I think more research would show more specificity and a designed system for this organism.
ReplyDelete1. Lamprey's are observed to have an adaptive-like immune system, that is similar to the B and T cells found in the mammalian adaptive system. The gene in the Lamprey's VLRB seem to express itself as a human B cell and the gene VLRA expresses itself as a T cell. Very similar to a human's adaptive immune system in its response, however is this similarity a part of design or is this evidence of a transitional form of an adaptive immune system? It is too early to say given the knowledge we have now of the adaptive immune system found in Lampreys. However a similar adaptive immune-like response is found within earthworms when their skins were transplanted between each other. There are similarities between the lamprey and the earthworm in their responses. Their responses have the same result of the adaptive response found in mammals, however the mechanisms for the adaptive-like immune system for both the lamprey's and the earthworms are not well known. For an evolutionist to call this a transitional form of the adaptive immune system found in mammals is premature, there is no evidence found which points to the adaptive immune response of lamprey's being inferior to the adaptive immune response found in mammalians. For a creationist one could argue that though invertebrate do not have an adaptive immune system like mammalians it could be possible that they have different ways of overcoming this as they still have a similar adaptive response.
ReplyDeleteEvolution considers physiological systems like the immune system to have preexisted the evolution of a specialized antibody-producing cell.
ReplyDeleteHowever, the evolutionist would also argue that a ‘primitive’ species ability to survive for millions of years is due to its advanced ability to adapt and survive. The immune system then would be a primitive and advanced system, which doesn’t support accidental or random theories of evolution but rather an intentional design of a thoughtful creator.
The notion that the title primitive is synonymous with lower class or undeveloped species is incorrect. A less developed species cannot be both ill equipped fro survival and overdesigned/ advanced in its ability to protect itself from disease and harm. The immune system then appears to be a brilliant display of complexity and intentional planning on the part of a designer so that an ancient species could survive and develop for incredible amounts of time. When scientists discover a high functioning immune system within a current species today and then find evidence of that system in ‘primitive’ species from the past, this is evidence that immune systems were designed very effectively for their purposes.
-Jon M.
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ReplyDeleteThe question of whether invertebrates (specifically jawless fish) possess intermediate or transitional adaptive immune systems is one that appears to be answered by your viewpoint: regardless of what is discovered, the evidence is interpreted through the worldview lens. Much research has been done on jawless fish, as evolutionists believe they are an important link in the chain. However, despite the evidence suggesting that VLRs point to adaptive immunity, some authors will ‘reclassify’ either the organism or the immune function. Usually this is done to preserve the notion either that jawless fish are truly that necessary link or that their immune systems prove that. From what I see, I would call the lamprey’s immune system analogous to that found in mammals in that it serves the same or similar functions with some overlapping features. But the differences, particularly in VLRs and LRRs, do not suggest relation.
ReplyDeleteAnother consideration is the original created purpose of the immune system. Dr. Francis has talked about it in class: that before the Fall, the immune system may have been a means for interacting with the microbial environment. If that was its purpose, God could have easily made these creatures with a different, but similarly functioning system to interact with microorganisms. Additionally, more research could make it more clear why this system could have been designed like this.
ReplyDeleteThe original purpose of the immune system is interesting. If "death" of plants is not considered evil and was obviously the case before the fall, ie. gardening, eating of the fruits. I wonder if death of microbes would be considered the same way. maybe our immune system isn't too far off what it is today, keeping foreign bacteria and materials out of our body. In this case, though, the immune system would be perfect of which our immune system is not today. Also destructive agents that are harmful must have had a "good" purpose before the fall as God did not create anything evil but perhaps the evolution (in the micro sense) of these organisms to become harmful is not as large a step as previously thought.
DeleteExcerpt from the conclusion of Phylogeny, longevity and evolution of adaptive immunity by Vinkler and Albrecht: “To achieve a correct insight into the ongoing evolutionary processes, immunologists will need to evade the traditional anthropormorphic view on animal phylogeny. Based on the current knowledge this view is erroneous and in nature we do not find any ‘higher’ and ‘lower’ organisms. If we miss this point we may achieve misunderstanding resulting from oversimplification. The vertebrate immune system is by no means ‘better’ than others. It is different. It may be more complex than some others because different are also the costs and benefits of bearing particular protective immunological mechanisms in individual taxa, depending on their ecological contexts.”
ReplyDeleteWith the recent findings of the lamprey adaptive-like immune system, it is hard to draw the line of the evolution of species. I believe that the scientific community is slowly but cautiously coming to grips with this fact. It seems that each organism, even these seemingly “less complex” organisms have quite an immune system and like others said, it seems even more complex than our own. Especially with the appearance of not just two but three VLR’s, it is very difficult to say that lampreys are an intermediate.
Recent studies in immunology concerning Jawless fish having a form of adaptive immunity raises the question, that is their immunity similar to mammalian immunity, and if its an intermediate system or not. New research according to ScienceMag.org states that, "the immune defenses of jawless fish such as lampreys generate as much diversity as the immune system that organisms from sharks onward in evolution use. And both employ a similar technique: rearranging DNA." Researchers don't know yet whether lamprey's immune system arose before our own or if it spun off from its own evolutionary tangent, but nonetheless, they are impressed by its complexity it possesses. David Davies of the National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda, Maryland who studies Toll-like receptors, and other immune proteins which recognize pathogens states, "It's just facinating that there's another adaptive immune system." The immune system in mammals, sharks and other vertebrates generates antibodies- proteins that notice an invading pathogen. The immune system adapts to these pathogens by rearranging DNA segments and inducing random mutations to give rise to millions of different protein possibilities, allowing the immune system to adapt to each new infectious "agent" that enters the body and boosting production of antibodies specific for that kind of pathogen or antigen.
ReplyDelete-P.F.
The immune system varies by the type of fish, but we know infact that these species do possess some sort of immune system. Certain species of sharks and rays have a more advanced immunity. The immune system by definition refers to a complex system that protects organisms against a certain substance that cause disease, the ability to recognize and respond to invading pathogens with specificity. The innate and adaptive responses are able to recognize foreign structures and trigger different molecular pathways depending on what system is activated. The point that we are trying to get at here, is that no matter what specific pathway is activated, the goal is trying to remove and/or eliminate that particular antigen. The immune response in fish compared to mammalian system differs in a few ways. For example, " Key immune mammalian homologous genes have been identified in several fish species, suggesting that the fish immune system shares many features with the mammalian system. For example, the identification of α and β T cell receptor genes (TCR), key T cell markers such as CD3, CD4, CD8, CD28, CD40L, and a great number of cytokines and chemokines suggest that T helper (Th)1, Th2 and Th17 and the regulatory subset Treg are present in fish. Some cell subsets have been better studied mainly because their activity can be easily differentiated and measured, as in the case of cytotoxic cells and macrophages. Finally, B cells have been much more studied due to the availability of monoclonal antibodies that have been isolated and identified by a number of techniques. Phenotypic characterization of leukocytes has been hampered mainly by the lack of membrane cell markers. Researchers anticipate developing antibodies for cell lineage markers of fish immunocompetent cells that can be used to isolate and characterize immune cells to obtain insights into their regulation and role in immune response." Having current knowledge of fish and related species gives us insight to their complex interactions. So, yes, fish do possess a certain kind of immune system with similar functions and ideas.
ReplyDelete-P.F.