Innate and Adaptive Immunity - Assignment Example

 Innate and Adaptive Immunity Question 1 Measles is an airborne disease that is highly contagious. Transmission can occur through contact with infectious mucus or saliva. The measles virus can remain airborne or thrive on infected surfaces for a maximum of two hours. The incubation period is usually 7-18 days. Infected persons are infectious 4 days before the onset of the rash up to 4 days afterwards. Measles antibodies are virus-specific proteins produced as an immune response to infection by measles virus or vaccination. There are two types of antibodies: IgM and IgG. IgM is the first antibody to appear after exposure or vaccination. IgG antibodies appear after a longer period and then remain in the bloodstream permanently, providing protection against re-infection (New Jersey Department of Health, 2011). In view of this, quarantine should be imposed on the patient if the IgM antibodies are present. This would mean that this is a case of first infection. Otherwise, the patient should not be quarantined. IgG antibodies can be present in blood because of vaccination (Lab Tests Online, 2012). Question 2 A secondary infection occurs when a pathogen attacks an organism whose immune system is weak due to an earlier infection. Secondary responses result from stimulation of B cells. The clonal expansion theory has three key areas: specificity, memory, and tolerance. Specificity comes about since production of antigen –specific antibody is in response to triggering of antigen-reactive clones. Memory is because subsequent responses to an antigen are stronger than the initial one. Tolerance is because of destruction of self reactive B and T cells. When an antigen with multiple epitopes gains enters the body, different clones of B cells recognize and produce antibodies against the different epitopes. The pathogens have antigens on their surface. Antibody response to protein antigen actively involves T cells and B cells. Since CD4 T lymphocytes stimulate B cells, they are known as helper T cells. Cytotoxic T cells kill other cells that virus-infected, allografts or cancer cells. Helper T cells secrete cytokines. Cytokines provide amplification mechanism by proliferation and differentiation (stimulation of B cell clonal expansion). They also determine the type of antibodies produced (Sridhar, 2012). Question 3 Human immunodeficiency virus (HIV) attacks a protein, CD4, on helper T cells of the immune system and associates with it. These cells are the immune system’s main infection fighting cells. T helper cells are necessary for activation of B-cells and cytotoxic T-cell immune responses. During this time, the body cannot make antibodies properly. Destruction of infected cells cannot occur without helper T-cells. Production of antibodies occurs in an effort to fight the virus. A HIV blood test is one that detects HIV antibodies. The body produces antibodies in response to HIV antigen. Therefore, in as much as the virus is destroying the helper T cells, the body continues to produce antibodies to fight the virus. These are the antibodies detected in a HIV antibody test. A negative result on a blood test means that either the person is not infected or that one is infected, but production of antibodies has not occurred. This is because, after the initial infection, it takes time for the body to produce antibodies. Seroconversion is the process of conversion from antibody negative to antibody positive blood (Melbourne Sexual Health Centre, 2007). Question 4 Innate immunity exists prior to antigenic exposure while adaptive immunity develops in response to antigen exposure. For adaptive immunity, resistance develops with repeated exposure to antigen, but for innate immunity, repeated exposure has no effect on resistance. Innate immunity is not specific to any antigen. Adaptive response, on the other hand, is antigenic specific. This means the ability to respond in a quickly during re-exposure to a pathogen (University of Arizona, 2008). Physical components of innate immunity include skin, mucus, coughing, and sneezing. Biochemical components of innate immunity include complements (such as lysis, opsonization and chemotaxis ), lysozymes, low pH and interferons. Crucial cells of innate immunity are phagocytes, monocytes (macrophages), dendritic cells and NK cells. Adaptive immune responses rely on B and T lymphocytes, which provide life-long immunity after exposure to pathogens and dendritic cells. Thus, dendritic cells function as an important intermediary between innate and adaptive immunity (Porth, 2010). Biochemical components of adaptive immunity include antibodies and lymphokines such as IL-2. Question 5 Sewage treatment is the process undertaken to render sewage fit to meet environmentally safe standards before discharge into the environment. There are three broad categories of treatment: primary, secondary and tertiary. Primary treatment of sewage is the treatment of sewage by a physical or chemical process or a combination of the two. The reduction in biological oxygen demand (BOD) of the incoming sewage is by at least 20% before discharge. The reduction in total suspended solids is by at least 50%. Sewage contains organic materials decomposed by microorganisms. BOD is the amount of oxygen consumed by these microorganisms as the organic matter decays. Dissolved oxygen (DO) is a measure of the dissolved oxygen. BOD of the water body increases with discharge of the sewage since the sewage still has a lot of organic matter. BOD directly affects DO. With increased BOD, reduction of oxygen occurs more rapidly in the water and, therefore, (DO) increases. Secondary treatment of sewage involves using aerobic and anaerobic processes to reduce substantially reduce the biological content of the sewage. With reduced organic matter the BOD in the receiving water, body increases, but to a lower extent when compared to primary-treated sewage. DO also decreases to but DO is higher for the secondary-treated sewage (United Nations, 2012). Question 6 Algal blooms form in fresh water when blue-green algae grow rapidly to form scum or mats in the water. Algae are photosynthetic organisms that vary from single celled forms to complex multi-cellular organisms. Algal blooms usually occur due to eutrophication accompanied by warm, sunny, and calm weather conditions. Human activity such as the addition of fertilizers containing phosphorus and nitrogen to crops can boost algal bloom. Agricultural runoff from fields can wash fertilizers into rivers and other sources of water. Treated wastewaters from sewage treatment plants and septic systems can be sources of nutrients in urban areas (Water Encyclopedia, 2012). An algal bloom forms on the surface of water, which accumulates downwind. The photosynthetic algae can lead to a severe reduction of oxygen in water causing the fish to die due to hypoxia. The algae block sunlight from reaching phytoplankton below the surface of water and consequently decreasing edible phytoplankton. Consequently, most of the fish die of starvation. The fish can also die due to mechanical disruption of the gill tissues by algae, which causes asphyxiation. Question 7 Fermentation is the breakdown of glucose under anaerobic conditions. It occurs when there is no oxygen to allow for production of adenosine triphosphate (ATP) by glycolysis. Metabolism of pyruvate to different compounds occurs in this process. Consequently, there are various types of fermentation (Life Science Leader, 2006). Homolactic fermentation is the conversion of pyruvate to lactic acid. Alcoholic fermentation is the production of ethanol and carbon dioxide from pyruvate. Heterolactic fermentation is the metabolism of pyruvate to lactic acid, alcohols, and other acids. Fermentation may cause a fall in pH of foodstuffs making it an extremely acidic environment. This bars harmful microorganisms from destroying the food. Vegetables such as cabbages are salted and allowed to ferment in a container. Creation of an acidic environment preserves the cabbage. Lactic acid bacteria have metabolites that have antimicrobial effects such as acetic acid and hydrogen peroxide. Preservation of animal feed involves controlled fermentation of green fodder having high moisture content. The silage material is stored under anaerobic conditions in pits. Organic acids such as lactic acid preserve the fodder. The fodder can be stored for use later in the year (Smallstock in Development, 2006). References Lab Tests Online, (2012). Measles and Mumps. Retrieved from http://labtestsonline.org/understanding/analytes/measles/tab/test. Life Science Leader. (2006)What is fermentation (Biochemistry)? Retrieved from http://www.bioresearchonline.com/doc.mvc/What-Is-Fermentation-Biochemistry-0001 Melbourne Sexual Health Centre. (2007). HIV Antibody Test. Retrieved from http://www.mshc.org.au/portals/_default/uploads/fact_sheets/hiv_antibody_test_a4.pdf New Jersey Department of Health, (2011). Recent Measles Cases in New Jersey. Retrieved from http://www.nj.gov/health/cd/measles/documents/measles_faq_clinical.pdf Porth C.M. (2010). Essentials of Pathophysiology: Concepts of Altered Health States (3rd ed.). Philadelphia: Lippincott Williams &Wilkins. Sridhar R.P.N. (2012). B Cell Activation and Humoral Immunity. Retrieved from http://www.microrao.com/micronotes/pg/humoral_immunity.pdf Smallstock in Development. (2006). Silage.Retrieved from http://www.smallstock.info/tools/feed/silage/silage1.html United Nations (2012). Waste water treatment. Retrieved from http://www.un.org/esa/sustdev/natlinfo/indicators/methodology_sheets/freshwater/waste water_treatment.pdf University of Arizona. (2008). Antigen Recognition: Innate and Adaptive Immunity. Retrieved from http://immunobiology.arizona.edu/files/InnateandAdaptive.pdf Water Encyclopedia (2012). Algal Blooms in Fresh Water. Retrieved from http://www.waterencyclopedia.com/A-Bi/Algal-Blooms-in-Fresh-Water.html Read More