What medical study focuses on the body's ability to fend off infections?

Immunology is the branch of medical science that specifically studies the immune system and how the body defends itself against infections and diseases. It encompasses the understanding of various components of the immune system, including cells, tissues, and organs that work together to protect the body from pathogens such as bacteria, viruses, and fungi. This field examines how the immune response is activated and regulated, as well as the mechanisms by which it can become impaired or overactive, leading to conditions such as autoimmune diseases or allergies.

Other fields like pathology focus on the causes and effects of diseases but do not specialize in the mechanisms of immune responses. Cytology studies cells in the context of their structure and function, without an emphasis on immune responses. Radiology involves the use of imaging technologies to diagnose injuries and diseases, but it does not examine the biological processes of immunity. Thus, immunology is distinctly aligned with the study of how the body combats infections.