(Image: Wikimedia Commons, CC BY 4.0) Exogenous antigens are foreign substances that enter the body from the external environment. Examples include bacteria, viruses, fungi, and other pathogens. These ...

The immune system responds to an infection by producing antibodies that recognize and bind to the cell surface of the pathogen, thus marking it as an intruder and triggering an immune response.

In many cases, an antigen is a bacterium, fungus, virus, toxin, or foreign body. But it can also be a cell that is faulty or dead. The immune system detects pathogen-associated molecular patterns ...

Antibodies and antitoxins are highly specific to the antigen or toxin that is made by the pathogen. That is why we say that the lymphocytes that produce them are specific.

Many pathogens evade the host's immune response by periodically changing their surface antigens so that existing antibodies no longer recognize them. "This strategy is known as antigenic variation ...

An important trigger for antigen switching is a double-strand ... but also many other pathogens. “Additionally, our study demonstrates the power of highly sensitive single-cell RNA sequencing ...