Fiction T - English - Chapters: Any substance that elicits a specific response by B or T lymphocytes.
Adaptive immune defenses 3 July The immune response to viral infection comprises innate and adaptive defenses. The innate response, which we have discussed previouslyfunctions continuously in a normal host without exposure to any virus.
Most viral infections are controlled by the innate immune system. However, if viral replication outpaces innate defenses, the adaptive response must be mobilized. The adaptive defense consists of antibodies and lymphocytes, often called the humoral response and the cell mediated response.
The ability to shape the response in a virus-specific manner depends upon communication between the innate and adaptive systems.
This communication is carried out by cytokines that bind to cells, and by cell-cell interactions between dendritic cells and lymphocytes in lymph nodes. This interaction is so crucial that the adaptive response cannot occur without an innate immune system.
The cells of the adaptive immune system are lymphocytes — B cells and T cells. B cells, which are derived from the bone marrow, become the cells that produce antibodies. T cells, which mature in the thymus, differentiate into cells that either participate in lymphocyte maturation, or kill virus-infected cells.
Both humoral and cell mediated responses are essential for antiviral defense. The contribution of each varies, depending on the virus and the host.
Antibodies generally bind to virus particles in the blood and at mucosal surfaces, thereby blocking the spread of infection.
In contrast, T cells recognize and kill infected cells. A key feature of the adaptive immune system is memory.
Repeat infections by the same virus are met immediately with a strong and specific response that usually effectively stops the infection with less reliance on the innate system. When we say we are immune to infection with a virus, we are talking about immune memory.
Vaccines protect us against infection because of immune memory. The first adaptive response against a virus — called the primary response — often takes days to mature.
In contrast, a memory response develops within hours of infection. Memory is maintained by a subset of B and T lymphocytes called memory cells which survive for years in the body.NK cells form holes in their targeted cells, causing them to apoptosis (cell destruction from within-out) destroy a wide variety of unwanted cells, including virus-infected cells, bacteria-infected cells, tumor cells, and cells of transplanted tissue (figure c).
Diet is the #1 contributor to global disease burden, even beyond smoking; A plant-based, whole-food diet has been shown to decrease your likelihood of getting a panel of diseases. Herd immunity a. only occurs in a population in which all individuals are immune. b. occurs in a population in which a large percentage of the population is immune.
IMMUNITY TO PARASITES T cells, cytokines and immunopathology Two major subsets of T cells, the helper (Th) phenotype and the cytotoxic/suppressor cell (T c) have been identified in most mammals and the advent of sophisticated molecular techniques has established that T cells, when activated.