Immunity In Practice

Guest post by CJ .M. Swaby

Immunity in practice

Lets face it, if you weren’t too fussed about the function of your immune system, with the recent  COVID-19 pandemic  wrecking everything from your health, our social fabric  to the global economy, it would seem that immune support has grabbed  the public attention – and rightly so.

Immune function is a complex business. How we go about supporting it can depend on factors such as your age, current health status, existing medical conditions, medications you are currently  on, pregnancy and more. 

This article is not definitive or prescriptive, nor do I pretend that it is. 

​But what this article will give you, is a brief overview of the different types of immunity, what practical things you can do to support your immunity, then specifically information regarding COVID-19.

This will all be evidence based. Sources will be provided, so that you can follow up and do your own research. There will be no fairy tales,  pixie dust, or conspiracy theories. Just solid, quality information.

​Keeping it simple

Whole Body Defence

You immune system is a complex series of physiological mechanisms, it involves each system in the body to ensure, swift, appropriate, and effective response – but sometimes this defence system can become a little over zealous, or dysfunctional leading to auto-immune conditions, inflammatory conditions and allergies. 

Your immune response has a varied arsenal to deal with any attack. It’s response will depend on various factors, including  whether the attack is a bacteria or virus, versus a parasite or allergen.

Essentially there are three lines of defence, as outlined below.

Lines of defense

First Line of Defence

Physical Barriers – This includes skin and mucous membranes of the gut and respiratory tract.

Second Line of Defence

Innate Immunity – detects and neutralises pathogens, initiates an inflammatory response. Communicates with the 3rd Line of Defence.

Third Line of Defence

Adaptive Immunity – Provides a specific, tailored response. Stores a strategic plan to battle pathogen should it arise again.


First Line of Defence – Skin and Mucous Membrane

These provide a physical, connective tissue barrier, to help prevent antigens entering through the skin, through inhalation or ingestion.

Antigens often first make contact through this first line of defence, triggering a network of immune cells and signalling molecules to interact and launch an attack.

Mucosal immunity is provided by Mucosa Associated Lymphatic Tissue (MALT) and Gut Associated Lymphatic Tissue (MALT).
Second Line of Defence – Innate Immunity

Think of innate immunity like the Army and  specifically ground troops. A range of cells and proteins are deployed to neutralise or destroy pathogens. Well trained,  they have a broad range of skills and weapons to utilise. 

Macrophages – these have developed from monocytes made in bone marrow, migrated from blood  to tissue. They essentially rough up invaders and then destroy them. They can also recruit other immune cells for back up.

Neutrophils – these guys are fast -acting “trigger happy” phargocytes (“phargo” – to eat or devour  “cyte”  – meaning cell).

They travel the blood stream probing vessels for signs of inflammation so they can deal with the matter. They are your primary  immune cell defence against bacterial infection. 

​Sneaky and resourceful little chaps, they can also team up with other proteins to  form traps for pathogens outside of cells. These traps are  known as NET’s (Neutrophil Extracellular Traps).

NK cells –  large, fast acting bad boys,  immune cells that can kill abnormal cells. No messing.  

There are many more involved, but these are some some of the key players.
Third Line of Defence – Adaptive Immune System

If the second Line of defence is the regular army, think of this line of defence as the Special Forces. These are your Marines, The Navy..(you get the idea).

The adaptive immune system is more specialised specific response unit,  the main players in this squadron are your and B cells. 

T-cells  mission is to carry out what is known as “cell-mediated” immunity (cells against cells). They react specifically and have  receptors on their cell surface which correspond to a protein sequence on a specific antigen (the bad guys). 

These assassins directly attack  and destroy other cells with the same specific antigen presented, this is done through various mechanisms.

T-cells that have encountered an antigen once, stay in the system to enable a faster more effective response when challenged with the same antigen in the future. 

B-Cells manufacture immunoglobulins, a form of specialised protein (glycoprotein) that circulate in the blood and binds to antigens.

There are different types of Immunoglobulins, they have a region which corresponds to a specific sequence of amino acids on a specific antigen (the “bad guys”).

  • IgM – The initial antibody produced in an immune response
  • IgG – The most prolific. Provides the majority of immunoglobulin based immunity against pathogens (the “bad guys”).
  • IgE – Promotes Histamine release. Involved in  allergic reactions and parasitic infections.
  • IgD – Functions as a receptor on B Cells that have not yet been exposed to the antigen.
  • IgA – Present in secretions, including tears, saliva, mucus, and beast milk. Stops infectious agents at barrier membranes by binding to pathogens and bacterial toxins, preventing bacterial adhesion.

Immunity: Putting it All Together

Lets keep it simple.

Immune function overall depends on key nutrients, especially Vitamin A [Source:1A], Vitamin C [Source 1B], Zinc [Source 1C], and Iron [Source 1D], they are all key players in white blood cell proliferation, antioxidant activity and immune cell differentiation. 

Your immune cell function is also highly dependent on vitamin D, receptors are present on immune cells such as B cells, T cells and antigen presenting cells.

Therefore Vitamin D plays a crucial role in your Innate Immunity (2nd Line of Defence) and Adaptive Immunity (3rd Line of Defence).  A deficiency in vitamin D is associated with an increase susceptibility to infection [Source 2A].

Poor digestion or gut function can lead to a weakened 1st Line of Defence,  impaired nutrient absorption. Poor fat digestion can also impair the utilisation of fat soluble vitamins D and A (important for immune function).

So when it comes to immune support the key nutrients to focus on depending on your health status are

  • Vitamin A
  • Vitamin C
  • Vitamin D
  • Zinc 

 If you do this, primarily through food, and careful supplementation, you are giving your body a winning chance. Probiotics to support gut function is also a good look.

Also remember that the following can lead to low immunity and impair your body’s ability to fight back

  • Chronic Stress (like a Pandemic, Financial, Emotional, Environment)
  • Over training (HIIT training too often, Long endurance style training)
  • Insufficient Sleep (get 7hrs+ if not 8+ or more)

I urge you to put things in place to help you manage these factors.

When it comes to COVID-19 there are many weird and wonderful recommendations out there.  

I’ve found this Bio Care article the most sane, sensible and evidence based when it comes to providing information on how to protect yourself from infections in general.   Definitely worth a read.

A big thank you to Cj for providing this guest blog full of useful information on immunity. Here’s a little bit about him.

Cj Swaby is a UK based  Online Coach, Health Alchemist, Nutritional Therapist and Speaker.   He has over 20 years experience, nationally and internationally as a coach and educator.

His mission is to  provide solutions for greater health and optimal human performance.  No sugar coating, no false promises, just real, achievable, sustainable results based on his 5 Pillars of Health; Mindset, Training, Nutrition, Recovery and Emotional Mastery.

You will find Cj working with men an women from all walks of life, from athletes, to every day fitness warriors and those with medical conditions – both online and in person.

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