IgG, or Immunoglobulin G, is a type of antibody found in blood and other bodily fluids. It plays a crucial role in the immune system by identifying and neutralizing pathogens like bacteria and viruses. IgG is the most abundant antibody, making up about 75% of the antibodies in the bloodstream. IgG is produced by B cells, a type of white blood cell, in response to infections or vaccinations. It can provide long-term immunity, as it remains in the body after an infection has cleared. This makes IgG important for both immediate and lasting protection against diseases.