Editing Immunology (section)

== Classical immunology ==
Classical immunology ties in with the fields of [[epidemiology]] and [[medicine]]. It studies the relationship between the body systems, [[pathogen]]s, and immunity. The earliest written mention of immunity can be traced back to the [[plague of Athens]] in 430 BCE. [[Thucydides]] noted that people who had recovered from a previous bout of the disease could [[nurse]] the sick without contracting the illness a second time.<ref>{{Cite web|url=http://nfs.unipv.it/nfs/minf/dispense/immunology/immun.html|title=The Concept of Immunity. History and Applications.|last=Gherardi|first=E|date=2007-01-02|website=Immunology Course Medical School, University of Pavia|archive-url=https://web.archive.org/web/20070102170207/http://nfs.unipv.it/nfs/minf/dispense/immunology/immun.html|archive-date=2007-01-02|access-date=2018-07-27}}</ref> Many other ancient societies have references to this phenomenon, but it was not until the 19th and 20th centuries before the concept developed into scientific theory.

The study of the molecular and cellular components that comprise the immune system, including their function and interaction, is the central science of immunology. The immune system has been divided into a more primitive [[Innate immunity|innate immune system]] and, in [[vertebrate]]s, an [[Adaptive immunity|acquired or adaptive immune system]]. The latter is further divided into [[Humoral immunity|humoral]] (or [[antibody]]) and [[Cell-mediated immunity|cell-mediated]] components.{{citation needed|date=June 2022}}

The immune system has the capability of self and non-self-recognition.<ref>{{cite book |first1=Robert R. |last1=Rich |first2=David D. |last2=Chaplin |year=2019 |chapter=The Human Immune Response |doi=10.1016/B978-0-7020-6896-6.00001-6|title=Clinical Immunology |edition=5th |series=Principles and Practice |pages=3–17.e1 |isbn=9780702068966 |s2cid=88829315 }}</ref> An antigen is a substance that ignites the immune response. The cells involved in recognizing the antigen are Lymphocytes. Once they recognize, they secrete antibodies. Antibodies are proteins that neutralize the disease-causing microorganisms. Antibodies do not directly kill pathogens, but instead, identify antigens as targets for destruction by other immune cells such as phagocytes or NK cells.

The  (antibody) response is defined as the interaction between antibodies and [[antigen]]s.<ref>{{cite book |last1=Janeway |first1=Charles A |last2=Travers |first2=Paul |last3=Walport |first3=Mark |last4=Shlomchik |first4=Mark J. |name-list-style=vanc |title=Immunobiology the immune system health & disease |date=2001 |publisher=Garland |location=New York |isbn=978-0-8153-3642-6 |edition=5th |chapter=Chapter 9: The Humoral Immune Response |chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK10752/ |url=https://archive.org/details/immunobiology00char }}</ref> Antibodies are specific [[protein]]s released from a certain class of immune cells known as [[B cell|B&nbsp;lymphocyte]]s, while antigens are defined as anything that elicits the generation of antibodies ('''anti'''body '''gen'''erators). Immunology rests on an understanding of the properties of these two biological entities and the cellular response to both.<!-- which can not only kill infected cells in its own right, but is also crucial in controlling the antibody response. Put simply, both systems are highly interdependent-->

It is now getting clear that the immune responses contribute to the development of many common disorders not traditionally viewed as immunologic,<ref>{{Cite web|url=https://www.immunology.org/public-information/what-is-immunology|title=What is immunology? {{!}} British Society for Immunology|website=www.immunology.org|access-date=2018-07-21|archive-date=2018-07-21|archive-url=https://web.archive.org/web/20180721073046/https://www.immunology.org/public-information/what-is-immunology|url-status=dead}}</ref> including metabolic, cardiovascular, cancer, and neurodegenerative conditions like Alzheimer's disease. Besides, there are direct implications of the immune system in the infectious diseases (tuberculosis, malaria, hepatitis, pneumonia, dysentery, and helminth infestations) as well. Hence, research in the field of immunology is of prime importance for the advancements in the fields of modern medicine, biomedical research, and biotechnology.