How Do Antibodies Work?

Active immunity occurs when an individual's own immune system responds to a pathogen or vaccine by producing its own antibodies and memory cells, providing long-lasting protection.

Passive immunity is the transfer of active humoral immunity, in the form of ready-made antibodies, from one individual to another. Because the recipient's body does not produce its own antibodies, this immunity is temporary.

Diphtheria toxin is an exotoxin that binds to cell receptors, enters the cell, and inhibits protein synthesis, causing cells to stop functioning. This leads to systemic complications affecting breathing, heart rate, and kidney function.

Without neutralizing antibodies, diphtheria toxin can enter the bloodstream and damage various tissues throughout the body, particularly targeting nerve cells, heart muscle cells (myocarditis), and kidney cells.

Antibodies are crucial because they bind specifically to foreign antigens (like viruses or toxins), neutralizing them by physically blocking them from attaching to and infecting host cells.