Khus and Immune System (DTE 1 - 15 November 2020)

Khus

Khus Grass Ensures
  • Kerala, the grass is extensively grown in the littoral sandy soil to protect the coastal areas from sea level rise.
  • Khus grass ensures that pools of standing water do not form on the land. By ensuring even distribution of water, it helps maximize its use.
  • Recent use – carbon sequestration - more efficient at sucking carbon dioxide from the atmosphere – teak, poplar, and eucalyptus
  • Central Institute of Medicinal and Aromatic Plants, Lucknow, has recently developed an efficient, low-cost khus root digging implement, which it says can reduce the digging cost by 80%

Immune System

Immune System
  • Innate immune system is the first line of defense against any incoming threat and consists of physical barriers like skin, airways and mucous layer of the digestive tract, and a cavalry of white blood cells that keeps circulating the body like a vigilant force. They are constantly on the lookout for foreign antigens, which are typically proteins on the surface of the invading bacteria or viruses. Some of its fierce personnel include phagocytes that simply swallow up the pathogens within minutes of getting alerted about an intrusion. Fever is the most common symptom of this war.
  • B cells tailor-make immunoglobulins (Ig) , or antibodies specific for the antigen. These antibodies neutralize the pathogen by binding to its antigen and thus preventing it from attaching to host cell and entering it. For those pathogens that have already invaded the host cells, it calls upon T cells. The cytotoxic T cells CD8 + neutralize the pathogen by directly destroying infected cells where the pathogen is multiplying, while helper T cells CD4 + coordinate further attacks on the pathogen
  • Some of the B and T cells develop memory which can persist for decades or even for a lifetime and settle inside the lymphatic organs and tissues, such as spleen and thymus. These do not prevent reinfection but remember every pathogen they have ever overcome.
  • Vaccination works by exposing an individual to a pathogen or an antigen in a controlled manner, without making them sick, and creates memory cells against it that fight the disease
  • Viruses that cause common cold, do not elicit a strong immune response, and thus do not leave behind much of a memory. This makes us vulnerable to reinfection. Even vaccines against such viruses require regular booster shots to maintain immunity. Viruses are also quick to mutate and this makes immune memory against them useless
  • Even antibodies, which are mere proteins and thus degrade over time, do not guarantee long-term immunity
  • Covid-19 patients with high levels of cytokines are less likely to develop long-term immunity - spleen and lymph nodes of deceased covid-19 patients showed a distinct lack of germinal centers, which are integral in developing long-term immune response
  • Asian Indians have gained more genes that protect them from viral infections during evolution
  • Two families of genes play in this protective function — one is KIR (killer Ig-like receptor) genes and the other is HLA (human leukocyte antigen) genes. Indians have more kir genes compared to the Chinese & Caucasians. These genes enable Natural Killer cells
  • Humans migrated from Africa to India, they gained newer genes to help them adapt to the changing environment. People who reached the coastal areas, retained these genes as the environment there was variable too. On the other hand, those who reached the plains of China, where the environment is stable, lost the genes.
  • The mice fed with the Western diet — high in salt, sugar, and fat — had higher number of immune cells like granulocytes and monocytes (part of the innate immune system) . When the mice went back to low-fat diets, their inflammation levels went down, but the genetic reprogramming of their immune cells continued. This is called trained innate immunity
  • A diet rich in fiber can improve immunity by improving the gut microbiota. A high-fiber diet improves gut microbiota which in turn increases the production of short-chain fatty acids which can then dampen the innate immune response that is typically associated with tissue damage
  • In vitro studies show processed, simple sugars reduce white blood cell phagocytosis and possibly increase inflammatory cytokine markers in the blood. Meanwhile, complex carbohydrate fiber, such as that found in fruits and vegetables, appear to reduce inflammation in both humans and mice.

Examrace Team at Sep 1, 2021