Pathogenic bacteria are known for their ability to cause diseases in humans and animals. They have developed different mechanisms to invade and survive in the host`s body. One of these mechanisms is the secretion of antigens.

Antigens are substances that can stimulate the immune system to produce an immune response. When pathogenic bacteria secrete antigens, it means that they release these substances into the host`s body. This action triggers the immune system to recognize the presence of the bacteria and mount a defense response to eliminate them.

It is important to note that the other options mentioned in the question are not correct. Antibodies are produced by the immune system in response to the presence of antigens, but they are not secreted by pathogenic bacteria. Hormones and interferons are also not secreted by pathogenic bacteria.