3 types of immunity: Your best defence vs coronavirus

There are three subsystems within your immune system — innate (non-specific), adaptive (specific) and passive (borrowed). They are closely linked and work together. Now, the world’s top minds are racing against time to produce a vaccine against the deadly COVID-19. Until then, your best defence is your own immune system. Find out how it works, and how you help boost it.

IMMUNITY TYPES: (1) Innate immunity includes the external barriers of our body — the skin and mucous membranes of the throat and gut. This response is more general and non-specific. (2) If the pathogen manages to dodge the innate immune system, adaptive or acquired immunity kicks in. Adaptive immunity protects us from pathogens. It develops as we go through life. As we are exposed to diseases or get vaccinated, we build up a library of antibodies to different pathogens. This is sometimes referred to as "immunological memory" because our immune system "remembers" previous enemies.

BORROWED IMMUNITY: (3) Passive immunity is a type of immunity that is "borrowed" from another source. For instance, a baby receives antibodies from the mother through the placenta before birth — and in breast milk following birth. This passive immunity protects the baby from some infections during the early years of their life.

LOOKING BACK: During the Spanish flu pandemic, 1928-20, [https://bit.ly/2vYTVxJ], case results based on published peer-reviewed medical literature demonstrated how transfusions of convalescent serum (blood products obtained from survivors) may have contributed to a 50% reduction in deaths among severely-ill patients. During the Ebola and avian flu outbreaks, convalescent plasma-derived therapy was also used to treat patients, according to a US National Institutes of Health Study in 2011 [1] https://www.ncbi.nlm.nih.gov/pubmed/16940336/] [2] https://bit.ly/38FKJM]f

CLASS OF PROTEINS: In biochemistry, "immunoglobulin" is any of a class of proteins present in the serum (a yellow-coloured, protein-rich liquid which separates out when blood coagulates) and cells of the immune system, which function as "antibodies". Serum also refers to the blood serum of an animal used to provide immunity to a pathogen or toxin by inoculation or as a diagnostic agent.

5 IMMUNOGLOBULIN CLASSES: There are five immunoglobulin classes (isotypes) of antibody molecules found in serum: IgG, IgM, IgA, IgE and IgD. They are distinguished by the type of heavy chain they contain. IgG molecules possess heavy chains known as γ-chains; IgMs have μ-chains; IgAs have α-chains; IgEs have ε-chains; and IgDs have δ-chains.