aglutinação

Aglutinação is a biological process involving the clumping together of particles. In immunology, it most commonly refers to the reaction between an antibody and an antigen on the surface of a cell, such as a bacterium or red blood cell. When specific antibodies bind to these surface antigens, they can bridge the particles, causing them to aggregate into visible clumps. This phenomenon is the basis for several diagnostic tests.

For example, the ABO blood typing system relies on aglutinação. Red blood cells have specific antigens (A and B) on their surface. If a person's blood is mixed with antibodies against the A antigen, and aglutinação occurs, it indicates the presence of A antigens on the red blood cells. Similarly, mixing with anti-B antibodies reveals the presence of B antigens. The absence of aglutinação with either antibody indicates the absence of that corresponding antigen.

Beyond blood typing, aglutinação tests are used to detect the presence of specific antibodies in a patient's serum, which can indicate exposure to certain pathogens. The principle remains the same: if the antibodies in the serum are specific to the antigens on the test particles, aglutinação will occur, signaling a positive result. This simple yet effective reaction has made aglutinação a fundamental tool in clinical diagnostics.