TOPIC 5 - AUDIO TO MEMORIZE SHIT

Biological Agents and Immune Regulation

Exposure and Immune Regulation

  • The lecture focuses on biological agents and their relationship to immune regulation.
  • Different exposures exist even within the same country.
    • Rural areas: Primarily exposures linked to infectious diseases.
    • Urban areas: Primarily exposures linked to inflammatory, non-communicable, or autoimmune diseases.
  • Urban areas have seen increased sanitation and vaccination, leading to a decline in infectious diseases.

Family Nucleus Hypothesis

  • Larger families (more family members) tend to have more trained and regulated immune systems compared to smaller families.
  • Individuals from smaller families are potentially more susceptible to allergic diseases due to a less trained immune system.

Hygiene Hypothesis

  • Early exposure to a diverse microbiome trains and supports the immune system.
  • Living in very clean environments with limited microbiome exposure can increase susceptibility to immune diseases, asthma, and allergic diseases.

Farm and Traditional Lifestyles

  • Larger families living close to farms and animals develop a greater microbiome exposure.
  • This exposure leads to a more robust immune system and increased immunity to potential allergic diseases.
  • Reduced contact with animal and environmental microbiomes is associated with a reduction in immune system diversity and a higher risk of allergic conditions.

Old Friend's Hypothesis

  • Focuses on exposure to specific "old friend" microbiomes that co-evolved with humans.
  • These non-pathogenic microbiomes are crucial for immune regulation and training the immune system.

Helminth Hypothesis

  • Helminths (parasitic worms) can modulate the immune system to promote immune tolerance.
  • Exposure to helminths can reduce the risk of allergic diseases as helminths regulate the immune system.
  • Eradication of helminths through anti-helminth treatments may disrupt this immune modulation, potentially increasing the risk of asthma and allergic diseases.

Microbiome Biodiversity Hypothesis

  • Contact with diverse microbiomes found in nature (soil, plants) enhances immune regulation and reduces inflammation.
  • Reduced contact with this diverse microbiome increases the risk of inflammation and immune dysregulation.
  • This is a key point related to biomedicine, dysbiosis and drift that we discussed in previous classes.

Synthesis of Hypotheses

  • Hygiene Hypothesis: Being too clean leads to less immune training, affecting the development of all types of microbiomes.
  • Old Friend's Hypothesis: Focuses on specific, co-evolved microbiomes (soil, gut flora) that contribute to immune tolerance.
  • Helminth Hypothesis: Helminths modulate the immune system to promote immune tolerance (when present in small quantities).
  • Microbiome Biodiversity Hypothesis: Contact with nature and environmental microbiomes (plants, soil) is crucial for immune regulation.

Practical Considerations

  • Simply rolling in dirt is not the solution; moderation is key.
  • Suffering from infectious diseases is detrimental to immune health.
  • Urbanized systems can adapt by using probiotics and prebiotics to enhance microbiome diversity.
  • Experimental treatments involve administering helminth eggs or derived molecules to train the immune system.