Within the gastrointestinal tract of the human body thrive trillions of bacteria, comprising what is known as the microbiota (Slack et al. 2009, Figure 1). The microbiota can be defined as the combination of microorganisms living simultaneously in a location, with that location being the human body (Round et al. 2009). Many years of evolution have contributed to the relationship that is observed between human intestinal bacteria and the adaptive immune system. Contrary to the common belief that all intestinal bacteria are pathogenic, recent evidence suggests that the bacteria residing in the human gut actually play a crucial role in human adaptive immunological function.
Vertebrate Immune System Divergence
The ability to evade pathogens using various immunological strategies is something that all multicellular organisms are capable of (Boehm 2012). Before vertebrates existed, invertebrates relied exclusively on innate immunity as a line of defense. Near the beginning of this divergence, the lymphocyte cell emerged, marking the evolution of adaptive immunity (Slack et al. 2009). A lymphocyte is a type of white blood cell that undergoes self-renewal and plays a role in humoral and cell-mediated immune responses. Yet, the question remained as to what the advantage of evolving adaptive immunity amongst vertebrates actually was. Research has determined that hundreds of resident species of bacteria reside in the guts of vertebrate organisms, while less than ten bacterial species are usually found at any given time in the guts of invertebrates (McFall-Ngai 2007). This suggested that the lymphocyte-rich adaptive immune system found in vertebrates has evolved to manage various mutualistic species of bacteria found within the gastroi...
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...lowski, K. M., and C.R. Mackay. 2011. Diet, gut microbiota and immune responses. Nat Immunol 12(1): 5-9.
McFall-Ngai, M. 2007. Care for the community: A memory-based immune system may have evolved in vertebrates because of the need to recognize and manage complex communities of beneficial microbes. Nature 445: 153.
Pancer, Z., and M.D. Cooper. 2006. The Evolution of Adaptive Immunity. Annu Rev Immunol 24: 497-518.
Rook, G.A. 2013. Regulation of the immune system by biodiversity from the natural environment: An ecosystem service essential to health. P Natl Acad Sci USA 110: 18360-18367.
Round, J.L., and S.K Mazmanian. 2009. The gut microbiota shapes intestinal immune responses during health and disease. Immunology 9: 313-324.
Slack, E., et al. 2009. Innate and Adaptive Immunity Cooperate Flexibly to Maintain Host-Microbiota Mechanism. Science 325: 617-620.
In short, the book 'Deadly Companions: How Microbes Shaped Our History' explains the dynamism, the changing interactions between humans and microbes, and the way and extent to which these interactions have influenced the human cultural history. This book is very useful because it tell us that we must strive to understand what makes microbes successful as we are faced with unrelenting microbial drug resistance. Microbes mutate to fatal human pandemics and it’s for this reason that we need to adopt a microbe centric world views.
Litman, Gary W. ìSharks and the Origin of Vertebrate Immunity.î Scientific American November 1996: 67-71.
Kopp, Elizabeth, and Medzhitov, Ruslan. “A Plague on Host Defense.” The Journal of Experimental Medicine. .
Most of the time nonspecific defenses keep pathogens from getting into the body. Sometimes one can break through and cause a disease. This is where the immune system comes into use.
There are two different parts of the immune system. Innate immunity is the more general type; for this reason it is also called the nonspecific res...
1. EQ: How does the structure and function of my immune system keep me healthy?
To understand the human gut health and aetiology, the first step is to understand the gastrointestinal (GI) microflora and its distribution through the digestive system [2]. The human GI tract is inhabited by trillions of microorganisms, which together is known as the microbiota [5]. These microorganisms come from both archeal and bacterial domains. Bacteria are the predominant kingdom of organisms and it is composed mainly by five bacterial phyla: Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria and Verrucomicrobia [3]. The great majority of mammalian gut microbiota belongs to the three phyla: the Gram-negative anaerobe Bacteroidetes, the Gram-positive Actinobacteria and Firmicutes [5].
Lymphocytes aid the body in remembering and recognizing prior offenders that may invade again. Lymphocytes a...
... a large role and impact significantly on how the body reacts to other organisms and disease. The study was biased as only one ethnical group was tested on the Chinese, perhaps the suggestion of carrying out the same study on other ethnical groups could be explored and studied, by doing this it can be seen if the ethnical group impacts the gut microbes, and if a change in that would cause an effect on type 2 diabetes patients. The study made great use of all the different orthologues, categories and many different data bases, while compiling their own references and taxonomic indexes, while this was great, refereeing to too many data bases may confuse areas that you are looking at examining, it's important to keep on topic and evaluate in appropriately. The study left many others avenues opened and lots more research can be done to further understand their finding.
Work Cited Colby, Chris. A. Web. " An Introduction to Evolutionary Biology." 28 August 2015.
Our body consists of 90% of bacteria. That means that for every cell that we have in our body, we have 9 bacterial cells living along with it. Granted that most of the bacteria live inside the intestinal tract, but without a proper immune system keeping the digestive system in check, we would not be properly digesting food or have healthy bodies.
Seattle Education Project. (2013, November). STEP: The Immune System - An Overview, [Online]. Available: http://www.thebody.com/step/immune.html [11/12/14].
HJ, W., II, I., J, D., K, H., T, S., Y, U., et al. (2010). Gut-residing segmented filamentous bacteria drive autoimmune arthritis via T helper 17 cells. PubMed .
The immune system defends the body against foreign invaders through a sequence of steps known as the immune response. A network of organs, cells and tissues must work together in order to protect the body. The immune response can be divided into innate immunity and adaptive immunity, though these divisions are artificial and the system functions as a single unit.
DeVeale, B., Brummel, T., & Seroude, L. (2004). Immunity and aging: the enemy within?. Aging Cell, 3(4), 195-208.