Antibody response

Antibody response

Subject: Science and Technology

Context: Older people appear to have fewer antibodies against the novel coronavirus, a new laboratory study from Oregon Health & Science University (OHSU) suggests.

Concept:

The study has been published in the Journal of the American Medical Association emphasized that

• They measured diminished antibody response in older people, the vaccine still appeared to be effective enough to prevent infection and severe illness in most people of all ages.
• The youngest group all in their 20s had a nearly seven-fold increase in antibody response compared with the oldest group of people between 70 and 82 years of age.

Antibodies

They are proteins made by the immune system to fight antigens, such as bacteria, viruses, and toxins. The body makes different immunoglobulin to combat different antigens.

The five subclasses of antibodies are:

• Immunoglobulin A (IgA), which is found in high concentrations in the mucous membranes, particularly those lining the respiratory passages and gastrointestinal tract, as well as in saliva and tears.
• Immunoglobulin G (IgG),are involved in the secondary immune response (IgM is the main antibody involved in primary response). IgG can bind pathogens, like for example viruses, bacteria, and fungi, and thereby protects the body against infection and toxins. Comprising up to 80% of the antibodies found in the human body, IgG is the smallest, yet most abundant human antibody, and that of other mammals. IgG can be found in all bodily fluids, and is the only antibody that can protect a foetus by passing through the mother’s placenta.
• Immunoglobulin M (IgM),is the largest antibody, and it is the first antibody to appear in the response to initial exposure to an antigen. B-cells create IgM antibodies as a first line of defense. Their large size gives them excellent binding avidity, and can pick up trace amounts of infection to mark for recognition by phagocytes. IgM is primarily found in serum and due to its size, it cannot diffuse well, and is found in the interstitium only in very low quantities.
• Immunoglobulin E (IgE),which is associated mainly with allergic reactions (when the immune system overreacts to environmental antigens such as pollen or pet dander). It is found in the lungs, skin, and mucous membranes.
• Immunoglobulin D (IgD),which exists in small amounts in the blood, is the least understood antibody.