How Vaccines Protect Pigs from Respiratory Bacteria

A 1999 patent describing a vaccine for swine that uses specific bacterial proteins to trigger an immune response against the lung disease caused by Actinobacillus pleuropneumoniae.

What it covers

The patent details a vaccine composition designed to prevent pneumonia in pigs caused by the bacterium Actinobacillus pleuropneumoniae. It works by using specific transferrin binding proteins—molecules the bacteria use to steal iron from the host—as antigens to train the pig's immune system. By introducing these proteins, the vaccine helps the animal recognize and fight off the infection before it causes severe lung damage. The claims also cover the use of cytolysins, which are toxins produced by the bacteria, to further strengthen the immune response.

What it doesn't cover

• —Does not cover vaccines for humans or other species besides swine
• —Does not cover methods for treating respiratory infections caused by viruses
• —Does not cover generic iron-binding proteins from bacteria other than A. pleuropneumoniae
• —Does not cover diagnostic kits or methods for detecting the bacteria in the environment

The clever bit

The researchers targeted the bacteria's iron-acquisition system. By blocking the protein the bacteria use to steal iron, they essentially starve the pathogen while simultaneously marking it for destruction by the host's immune system.

Why it matters

Actinobacillus pleuropneumoniae is a major economic burden for the global pork industry, causing high mortality rates and significant losses. This patent provided a molecular blueprint for creating subunit vaccines, which are safer and more precise than older methods using whole, killed bacteria.

Real-world examples

• 1.Porcine respiratory disease vaccines
• 2.Bacterial subunit vaccines for livestock