Immune System
Poisons are defined as a substance that can cause illness or death of a living organism when introduced or absorbed. There are 4 main types of poisons that affect the immune system. These poisons are bio toxins, metabolic poisons, immunotoxins and chemical toxins. The normal immune response to any invasion or infection is to first have neutrophils attempt to destroy the invading pathogen and then in turn be ingested via endocytosis by macrophages which will display the antigen from the pathogen (IB Guides, 2012). The macrophage will in turn be destroyed by killer T-cells (produced via polyclonal response) and the memory B-cells will assist in the destruction of the pathogen if it enters the body again (IB Guides, 2012). For more detail see the About page of this website. However when any type of poison or toxin enters the body and targets the immune system, it is unable to carry out the proper response and it becomes compromised.
The first type of poison mentioned was a bio toxin. A bio toxin is a poisonous substance produced by a living organism, and there is a prime example of one that is more common than expected, mold. Mold is a fungus made from hyphae that often forms on old and decaying food. The reason mold is a bio toxin is that in large amounts mold has a negative effect on your immune system (Chesney, 2014). Usually the immune system would adapt and respond to an invading substance or pathogen. However large quantities of mold will block the Human Leukocyte Antigens (HLA’s) found on the surfaces of cells and prevent an adaptive response from happening causing the immune system to respond the same way to all pathogens (Chesney, 2014). This is known as Chronic Inflammatory Response Syndrome (CIRS) (Chesney, 2014). Another example of a bio toxin is Lyme disease (Chesney, 2014) (IB Guides, 2012)
The second type of poison mentioned was a metabolic poison. A metabolic poison is any substance that interferes with the use or production of energy (Sathasvian, 2013). A common example of a metabolic poison is cyanide. Cyanide acts as a metabolic poison by inhibiting cytochrome oxidase in the electron transport chain, thereby ending effective production of ATP and causing the cell to switch to anaerobic respiration (Sathasvian, 2013). Eventually lactic acid concentrations will have a large increase leading to lactic acidosis. Lactic acidosis is a specific form of metabolic acidosis in which large concentrations of acids build up in cells and tissues due to switching from aerobic to anaerobic respiration (Sathasvian, 2013). This affects all the leukocytes in the immune system, because even though they don’t have large numbers of mitochondria the minimal amount that they do have will be inhibited and will be unable to move to the site of infection to help prevent the spread and reproduction of the pathogen. Of course since it is a metabolic poison, it is far more likely that death will come first as the body is not able to respire efficiently but the immune system is also weakened
The third type of poison mentioned was immunotoxins. Immunotoxins are man-made proteins formed by combining wither an antibody or antigen with a toxin to help the immune system (Pastan I, 2007). An example of this is immunotoxins being used to kill cancer cells. The antibody found on the immunotoxin will bind to the surface protein of an antigen on the cancer cell and be taken in by endocytosis where the toxin will help kill the cell (Pastan I, 2007). However immunotoxins are not as effective as they seem because the immune system will often respond to the toxin found in the immunotoxin and prevent it from fulfilling its function (Pastan I, 2007).
The final type of poison mentioned is a chemical toxin. A chemical toxin is defined as chemicals that are used to kill or repel unwanted organisms. A prime example of a chemical toxin is potassium chloride (KCl), and this is because it stops the heartbeat by eliminating the cell potential caused by Ca² ions necessary for muscle contraction which is why in large doses it can lead to death (Niedergerke, 1956). An example of a chemical compound that directly affects the immune system however, is hexachlorobenzene (HCB) (Michielsen, Loveren, & JG, 1999). HCB was commonly found in seed treatments as a fungicide before it was banned from use (Michielsen, Loveren, & JG, 1999). HCB caused skin and lung lesions in humans by avoiding and inhibiting the normal T-cell immune response (Michielsen, Loveren, & JG, 1999). Research is still being done to determine the mechanism by which HCB inhibits the normal T-cell response.
Glossary
Poison- A substance that can cause illness or death of a living organism when introduced or absorbed
Metabolic poison- Any substance that interferes with the production or use of energy
Bio toxin- a poisonous substance produced by a living organism
Immunotoxin- man-made proteins formed by combining wither an antibody or antigen with a toxin to help the immune system
Chemical toxin- chemicals that are used to kill or repel unwanted organisms