Antibodies, also known as immunoglobulins, are specialized proteins produced by our immune system to identify and neutralize harmful invaders like bacteria and viruses.

The Y-Shaped Structure

Every antibody molecule has a unique shape that looks like the letter 'Y'. This structure is made of four polypeptide chains, which are long strings of amino acids. Two of these chains are 'heavy chains' (long) and two are 'light chains' (short). These chains are held together by strong chemical links called disulfide bonds. The tips of the Y-shape have a special area called the antigen-binding site. This site acts like a lock, designed to fit only one specific 'key' or antigen—a marker found on the surface of a germ.

How Antibodies Work

When an antibody finds its matching germ, it binds to it. This binding prevents the germ from entering our healthy cells. Once the germ is tagged by the antibody, it becomes easy for white blood cells to find and destroy the invader. This is the body’s way of marking the 'bad guys' for removal.

The Five Types of Antibodies

Our bodies create five different classes of antibodies, each with a specific job:

• IgG: This is the most common type. It circulates in the blood and can cross the placenta to protect a developing baby.
• IgM: These are the first responders. They are usually the very first antibodies produced when an infection strikes.
• IgA: These are found in body fluids like saliva, tears, and breast milk. They defend the surfaces of our body.
• IgE: These are primarily involved in allergic reactions and fighting off parasites.
• IgD: These are found on the surface of B-cells (special immune cells) and help activate the immune response.