How does tetanus antitoxin function?

Tetanus antitoxin functions by binding free toxin in the bloodstream. When tetanus toxins, specifically tetanospasmin, are produced by the bacterium Clostridium tetani, they can cause severe muscle spasms and rigidity by interfering with normal nervous system signaling. The antitoxin is made up of antibodies that specifically bind to these circulating toxins, neutralizing their harmful effects and preventing them from binding to neuronal tissues. This mechanism effectively interrupts the progression of tetanus symptoms since, without the free unbound toxin, neurological pathways critical for muscle control remain intact.

While the immune response to the toxin is certainly vital for overall protection against future infections, the function of tetanus antitoxin is primarily focused on neutralizing the immediate threat posed by the circulating toxin rather than stimulating that response. Similarly, enhancing muscle relaxation and inactivating GABA receptors relates to different physiological actions not directly served by the antitoxin's mechanism.