The specific failure of a normally responsive individual to make an immune response to a known antigen. It results from previous contact with the antigen by an immunologically immature individual (fetus or neonate) or by an adult exposed to extreme high-dose or low-dose antigen, or by exposure to radiation, antimetabolites, antilymphocytic serum, etc. (MeSH, 2024. Immune Tolerance https://www.ncbi.nlm.nih.gov/mesh/68007108)
Field of chemistry that pertains to immunological phenomena and the study of chemical reactions related to antigen stimulation of tissues. It includes physicochemical interactions between antigens and antibodies. (MeSH. 2024. Immunochemistry. https://meshb-prev.nlm.nih.gov/record/ui?ui=D007120)
Immunocytes are hemocytes with immune function and include phagocytes and cytotoxic cells. (John DeFilippo, Gregory Beck, Tunicate Immunology, Reference Module in Life Sciences, Elsevier, 2018, https://doi.org/10.1016/B978-0-12-809633-8.90288-7.)
Inability to produce an adequate immune response because of an insufficiency or absence of antibodies, immune cells, or both. Immunodeficiency disorders can be inherited, such as severe combined immunodeficiency; they can be acquired through infection, such as with HIV; or they can result from chemotherapy. (Office of AIDS Research. nd. HIV/AIDS Glossary. https://clinicalinfo.hiv.gov/en/glossary/immunodeficiency)
Biologically active substances whose activities affect or play a role in the functioning of the immune system. (MeSH. 2024. Immunologic Factors. https://meshb-prev.nlm.nih.gov/record/ui?ui=D007155)
The complex formed by the binding of antigen and antibody molecules. The deposition of large antigen-antibody complexes leading to tissue damage causes immune complex diseases. (MeSH. 2024. Antigen-Antibody Complex. https://meshb-prev.nlm.nih.gov/record/ui?ui=D000936)
Immunosuppression by the administration of increasing doses of antigen. (DeCS/MeSH. 2025. Desensitization, Immunologic https://decs.bvsalud.org/en/ths/resource/?id=29373)
Manipulation of the host's immune system in treatment of disease. It includes both active and passive immunization as well as immunosuppressive therapy to prevent graft rejection. (National Library of Medicine. MeSH (Medical Subject Headings), Immunotherapy, http://id.nlm.nih.gov/mesh/D007167)
Innate immunity: Physical and chemical barriers, cells, cytokines, and antiviral proteins which exclude, inhibit, or slow down infection with little specificity and without much adaptation or generation of a long-lasting protective memory. (Antiviral Innate Immunity: Introduction. Encyclopedia of Virology. 2021 : 577–583. doi: 10.1016/B978-0-12-809633-8.21290-9)
Adoptive immunity is immunity conferred on a naive or irradiated recipient by transfer of lymphoid cells from an actively immunized donor. This is called adoptive transfer or adoptive immunization. (Janeway CA Jr, Travers P, Walport M, et al. Immunobiology: The Immune System in Health and Disease. 5th edition. New York: Garland Science; 2001. Glossary. Available from: https://www.ncbi.nlm.nih.gov/books/NBK10759/)
