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?
Plants appear to have some intriguing immune functions and even bacteria express immunity to some viruses.
Discuss the evolution and design aspects of the immune systems found in plants, invertebrates, mammals, bacteria 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 October 14
All species and organisms have complex immune systems with similarities and discontinues. I do not think similarities provide evidence for a transitional immune system or that they suggest evolution. When studying fish, it is important to note that adaptive immune responses that we learn about in our textbooks really begin to occur in species like sharks and other jawed creatures. Anything previous to the shark or that “evolved” before the shark are said to have no adaptive immunity. This is what makes jaw-less fish so intriguing. Research has shown that these species can produce a type of adaptive response, not it lymphocyte structure but in function. In other words, they lack the ability to create antibodies and other factors but can produce something similar. It is currently undetermined what these factor like responses are, but they do know how they are activated. They are activated by VLRs (variable lymphocyte receptors), which like TLRs, activate a cascade of different events to start the adaptive like response. This does not support any sort of transitional immune system because the two immune systems are so radically different; a jawless fish immune system versus a mammal's. There is no genetic proof to connect the two systems to the same beginning. There is a lot of similarity in function but not structure, which once again is supported by genetics.
ReplyDeleteI appreciate Tim bringing up the point that some textbooks state that jawless fish, supposedly prior to the shark in the evolutionary chain, do not have an adaptive immune system because I feel that often in the scientific community certain theories are rather rapidly treated and taken as fact in order to support another theory rather actually performing the science and doing the research to prove or disprove such a theory. I think this would be a prime example of such a time. It is so unfortunate because instead of making the assumption and then regarding as fact that jawless fish must not have had adaptive immune systems more research should be done what the immune system of the jawless really is like and how they are able to survive if in fact they do not have an adaptive immune system or perhaps they do but that does not mean that it is going to look the exact same as a mammalian immune system.
DeleteAlso, I appreciate Tim's note about how the jawless fish do exhibit a type of adaptive immune system through VLR (like TLRs) in a cascading system. I find that absolutely fascinating and rather exciting because there is so much that can studied and learned from such a system that perhaps could be applied to a mammalian system, specifically humans, for those with immuno deficiencies perhaps.
To comment about the immune systems of bacteria, they also show a sort of adaptive immune system. They are able to kill and more importantly remember a virus. This all because of a gene in the bacterial genome called CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats). Research is still being conducted on this gene to see how it actually works in the bacteria and if it can benefit people in any way.
ReplyDeleteI think this goes to show that there really is no such thing as a simple immune system. Each immune system studied provides more and more complexity and information that baffles researchers today. The study of bacteria which is supposedly very simple and primitive still leaves people perplexed and speechless because of its intricacy. I am not sure how evolution can support an extremely complex immune system, for a bacterial immune system to evolve to another complex immune system (jaw less fish) and yet again to even more complexity in sharks. It seems to me that no matter what level of creature is studied there is still a myriad of information still misunderstood.
Hey Tim, I really liked your post on this topic. One specific part I resonated with was the last sentence above, where you mention that the real issue is that we lack a lot of information about these systems. I believe that scientists are too quick to assume evolutionary evidence, before accurate research is done to confirm or deny it. As I said in my post, the evidence we currently have seems to actually support the creationist's side. It will be interesting to see what more research discovers in this area of science!
DeleteThere are some interesting discoveries that have been made regarding immunological systems in differing types of organisms. One of the more interesting developments has been with plants. Plants seem to have a two-fold immune recognition to foreign material: common molecules of foreign bacteria and virulence factors. Thus, just like humans, plants contain pattern recognition receptors (PRR’s): NB-LRR (leucine-rich receptors like our TLR’s). Even though plants are unable to produce the adaptive immune system with B/T cells, they are able to protect themselves from invasive bacteria through an Innate system much like our own.
ReplyDeleteInvertebrates, mammals, bacteria, and fish also contain special immune systems that contain different components, yet at the same time perform the same function as humans and plants. Jawless fish like the lamprey produce variable lymphocyte receptors (VLR) are found on WBC’s. These VLR’s act identical to T cell receptors in humans. Bacteria and invertebrates likewise exhibit unique immune systems.
However, the question many scientists are asking is if these less complex immune systems form a type of “transitional” immune system. I personally do not believe that transitional immune systems exist, as there has been a stark lack of evidence. For a transitional system to exist, it would have to be somewhat incomplete or inefficient. But for all our research, it have shown these different organisms have complete immune systems that function almost identically. While some, like mammals and humans, have more complex systems (Adaptive), plants and bacteria have perfectly fine immune systems for their survival. Furthermore, while the systems themselves are similar across Kingdoms, the specific factors involved differ dramatically. As mentioned above, humans have TLR while plants have NB-LRR. Both perform the same task, but with different receptors. Thus, it is really hard for me to conceive of these immune systems from different Kingdoms having evolved from one another. Instead, there is a remarkable amount of evidence for a Creator who designed plants and invertebrates with more simple systems, while providing more complex systems for humans and other mammals.
Thanks Campbell for the interesting discussion. I as well have found the same result according to my research, that a transitional immune system just could not exist. You had a great point about the diversity between the human and plant pattern recognition receptors. Although function may be quite similar, the TLR in humans and NB-LRR in plants, each has a specific receptor that could not have evolved form the same form.
DeleteAfter reading Tim and Campbell's responses, I agree with both of them! I don't think there is enough evidence to prove a transitional type of immune system, and scientists are really quick to jump to conclusions about transitional forms, mostly claiming that it supports evolution. More importantly, I think that the similarities that we see between different species actually is a stronger argument for one Creator. If there is truly one Creator who brought all different kinds to life, which there is, then there should be similarities. If there was no similarities between the kinds on a molecular or broad scale, then this would go directly against the consistency of God's character.
ReplyDeleteSecondly, I think that people could argue that if we had a common ancestor, then those similarities would exist. But if we evolved at millions of years as evolutionary scientists claim, then the number of mutations present today should reflect that time. Our immune systems would be so different from what they were "back then" in bacteria and other "primitive" life forms. Each species would have developed their own immune system, depending on their environmental conditions, among other things. There is just too much time to reasonably believe that these similarities would still exist today. I don't have any scientific to support this opinion; I'm open to other thoughts :)
ReplyDeleteHey Shannon, this was an interesting post! Again, it seems that we all are on the same page when it comes to the evidence for a transitional immune system. That said, if I were to play Devil’s advocate for the evolutionist, I would say that the evidence of similar immune systems is really just evidence of natural selection. The really old bacteria that lacked effective systems died off, while those with more promising systems thrived. Thus, it would seem from an evolutionary perspective that all the immune systems we see today are almost identical in the end results, but composed of differing parts and functions along the way. We can see that while plants lack TLR’s, they make up for this by having a different receptor that performs the same thing (NB-LRR). The end result of a foreign bacterium inside a plant and a human are the same: elimination. These individual organisms “could” have developed immune systems that worked well in their environment.
DeleteThat said, I believe that the current evidence is a weak support for evolution, because as you said, a lot of factors would have to be present through mutations to evolve a working immune system. The thing is, evolutionists recognize this problem, but try to minimize the importance of it.
Anyway, just a few thoughts of mine.
Shannon, in your post you have really shown how because there is one Creator who has given life to all, then there would be similarities between organisms. You have said that if each species would have been able to develop their own mutations from a primitive life form then there should be evidence that shows these mutations. This would be like natural selection and each organism would either have to adapt to changing conditions or would die off. There is weak scientific evidence to prove that organisms have mutated and evolved to make a transitional immune system.
DeleteI really like this post Shannon!
DeleteI guess it just comes down to the fundamental belief of whether or not there is a God that is actively involved in His creation. The fact that people will believe the viewpoint that has the least evidence in support of it and that actually requires more faith doesn’t make sense. There are just too many things that have to be set up perfectly in order to successfully support life. There is not room for failure, no room to make further improvements. It had to be done correctly the first time. In response to Campbell’s comment, the evolutionary process would remove the species that were deemed unfit or lacking. The evolutionists are claiming that some of the species that are still around today evolved into the more “complex” species we see. If in fact they were the starting point, there should not be this level of similarity. Thankfully, Campbell does not believe this!
Shannon, really loved what you had to say and Campbell made a great point as well. In reading the post and then all the responses, I had an interesting thought that I would pose to the evolutionist and if anyone here has any thoughts please share. Setting natural selection aside for a moment, in the present we see very similar immune systems, significant differences but too many similarities for them to be completely removed from one another, and my question is why. I know that we could say due to natural selection which from the evolutionist stand point I can in fact understand however, the whole idea of evolution is literally evolve from the inferior to the superior. Thus as times goes on we should see less and less of one type of immune system either because of it's inability to protect an organism or natural selection. Yet still presently there are too many similarities in the different immune systems of varying species (essentially Shannon's point). My question then is does this evolution of immune systems seem to have stopped presently? It would appear that the evolution of immune systems would now be stagnate. In my understanding of evolution, essentially there has to be one winner. If evolution is the literal evolving into the most supreme (fill in the blank) then there would have to be a most supreme immune system. Yet that is not what we see. We see that from an evolutionary standpoint these immune systems are stagnate in that they are not evolving. Rather they are continuing on side by side promoting the lives of varies species in all different types of environments. I would, not at all in a condescending manner or to be argumentative, but genuinely have to ask the evolutionist why that is.
DeleteThe so-called “transitional” immune system would need to have evidence that there has been a lack of completion. If this theory were to be true, then when God made the world and in completion said that it was perfect would have to be a false statement. If our belief were in God as the creator then this theory would not go along with our beliefs. From evidence that has been shown many different organisms have a complete immune system that will have functions that are very similar to other organisms. Just as Tim, Campbell (Daniel), and Shannon have said in the previous comments, there has not been evidence that would prove a transitional forms in the immune system. Campbell pointed out a great fact that although function may be quite similar, the TLR in humans and NB-LRR in plants, each has their own receptors that leads to how could have these evolved from one another. Each organism has been created with a specialized immune system with different components that can have similarities to other organisms, but may not necessarily be made of the same components. Each system had to be made for the unique individual, no matter if it was a human or that of a bacterium. Each system needs to be specialized for the way of life each organism has. There has been no scientific evidence to prove that the immune system of one organism has been able to evolve into different forms to support a wide variety of organisms. Mutations would not be able to produce very different molecules and receptors that could have the function in diverse organisms.
ReplyDeleteDonny, I can see what you are getting at with “transitional” inferring that there be a lack of completion so this might be an improper way to describe it. However, I think that it is clear that the immune system that is manifested in fish has many similarities to both the innate and adaptive immune systems. Many of these similarities have been highlighted already: protective epidermis/external barriers, digestive juices, protective chemical layers (innate) as well as producing B and T cells, compliment, TLRs, and cytokines (adaptive). Based upon this I would assert that a better term would be a “hybrid” system. Though it should be noted that not every aspect of each system is present as also already mentioned.
DeleteWhen it comes to this hybrid system, I think that it should be looked at is how specifically it matches the environment and needs of the animals. This fact can support either the concept of evolution in that these creatures developed this immunity based on what their situation necessitated, or the wisdom of God to create fish with this hybrid system to perfectly match their environment.
The immune system varies in each species of fish. I believe our creator created them differently due to where each fish lives. Such as fish with jaws have no adaptive immunity, and actually have a higher core temperature because they are very active creatures. This could be why they have no adaptive immunity. But there is no concrete evidence to show this. Jawless fish tend to be relaxed swimmers and they have more complex systems. Also, what I found in research was that some fish such as hagfish had bone morrow which leads to advance immune systems. It is hard to say if they have a transitional immune system because each fish has different immune systems.
ReplyDeleteAs has mentioned by Tim, I am completely agreed that the similarities among the immune system could not suggest evolution. Aside from the similarities, some functions and structures of the subunits of immune system between organisms are not identical. By saying that the similarities between certain organisms are the evidences of evolution, then I’d wonder if dog and cat evolved from each other. What significant about plant immune system that makes it differed from others is that it can sense the presence of pathogens and the effects of infection via different mechanisms than animals. Adaptive immune response is defined by its ability to detect variable or unique single-gene product, whereas a transitional immune system recognizes more conserved structures or products of multigene pathways. Thus this transitional immune system functionally overlaps both the innate and adaptive responses. There are studies which have not yet been proven about the evolution on Teleost fish even though they found that its immune system is much similar to mammals. There is a successful development of fish rhabdoviral vaccines which suggests that vaccination may prove to promoting fish adaptive immune responses to viruses; further study is still conducted toward the evolution of fish immune mechanism. I think people are too quick to assume on the evolutionary just because of the similarities among organisms.
ReplyDeleteEvolutionists believe that the adaptive immune system in mammals, which is centered on lymphocytes bearing antigen receptors that are generated by somatic recombination, arose approximately 500 million years ago in jawed fish. Jawed vertebrates generate a diverse repertoire of B and T cell antigen receptors through the rearrangement of immunoglobulin. They assemble their variable lymphocyte receptors through recombinatorial usage of leucine-rich repeat (LRR) modular units.
ReplyDeleteAnother example of immunity components similar to mammals can be found in Hydra. There are two transmembrane proteins with LRR’s similar to LRRs present in vertebrate TLRs. These proteins lack any intracellular domain and, therefore, also do not contain the typical TLR domain. Thus in Hydra, the TLR function is present but is allocated on two different genes.
Just like previous posts have concluded, aside from some similarities, the immune structures are different between organisms. There is so much more to the adaptive immune system than common design aspects that are miniscule in the grand scheme of the overall immune system. These aspects are not due to evolutionary processes, because then there would be evidence of one type of animal evolving into another. I believe there is evidence for some type of transitional immunity. It seems as though each animal has been created to survive to its environment and adapt to whatever situation. That is all part of God's natural design!
Plants exhibit an innate immune system with two primary components. The first identifies and properly responds to certain classes of molecules that are often associated with microbes. The second involves the identification of the virulence factors of the pathogen. Invertebrates do not possess a humoral-based adaptive immune system but rather only have the innate immune system. They also contain Pattern Recognition Receptors that trigger proteolytic cascades that ultimately destroy proteins. Fish actually possess an antiviral interferon that immediately attacks the pathogen upon entry. I do not believe that fish, or any other transitional immune systems exist. The very concept implies that an evolutionary process is currently taking place. Moreover, each species is unique, despite the similarities. Evolution should theoretically develop a superior being. If this is true, anything that does not keep up will die off. Yet, the “simple” systems are still around today in great numbers.
ReplyDeleteTim makes a great point, the genetic information does not point toward the gradual change in the immune system. If there truly was an evolutionary process that resulted in the development of the adaptive immune system, a greater level of complexity would also have come about. Although they refer to the invertebrate immune system as “simple” or as being a precursor to the vertebrate immune system, it’s actually incredibly complex. Shannon makes a great point, the similarities among the various organisms do not support evolution but rather point toward a common creator!
I would like to expound a little further on the immune system of bacteria. The immune system that has recently come to light called the CRISPR-Cas, has many working parts and aspects—Aka: complexity. What has been found is that this system is able to generate new immunity by adapting to any mutations of viruses or plasmids, hold a genetic memory of past infections, transferring antibiotic resistance genes between bacteria, as well as many other functions. I don’t think that anyone would classify an immune system that expresses genetic resistance to pathogens as “simple” or “archaic” but rather “sophisticated” or “complex.” So even though many look at bacteria as some of the simplest of organisms and thus likely express a simple immune system, I think that this is a serious error of reasoning and, in fact, a very uneducated perspective.
ReplyDelete