Antigens that can stimlate antibody production only with help from T helper cells. Most protein antigens aer T-Dependent
An immune reponse in which an antibody binds to and blocks the ativity of an antigen.
An immune response in which the binding of antibodies to the surface of a microbe facilitates phagocytosis to the microbe by a macrophage
An antibody-mediated immune response in which bacteria or viruses are clumped together, effectively neutralized, and opsonized.
An immune response in which antigen-antibody complexes activate complement proteins
Membrane Attack Complex
-A molecular complex including complement proteins that generates a -nm diameter pore in a bacterial membrane, causing the cell to die.
The collective action of antibodies, complement, and phagocytes. Microbes coated with anitodies and complement proteins adhere to blood vessel walls, making the pathogens easier prey for phagocytic cells circulating in the blood.
A localized regin on the surface of an antigen that is chemically recongized by antibodies; also called antigenic determinant.
Temporary immunity obtained by acquiring ready-made antibodies or immune cells; lasts only a few weeks or months because the immune system has not been stimulated by antigens.
Natural Killer Cells
A nonspecific defensive cell that attacks tumor cells and destroys infected body cels, especially those harboring viruses.
A white blood cell; typically functions in immunity, such as phagocytosis or antibody production.
The name of the late stages of HIV infection; defined by a specific reduction of T cells and the appearance of characteristic secondary infections.
An RNA virus that reproduces by transcribing its RNA into DNA and then inserting the DNA into a cellualar chromosomes; an important class of cancer-causing viruses.
A T cell surface protein, present on most helper T cells, CD4 bind to part of the class II MHC protein.
T cell surface protein that enhances the intereaction between the antigen-presenting infected cell and a cytotoxic T cell.
A group of about 50 different proteins secreted by blood vessel endothelial cells and monocytes. Theses molecules bind to receptors on many types of leukocytes and induce numerous changes central to inflammation.
A large set of cell surface antigens encoded by a family of genes. Foreign MHC markers trigger T-cell responses that may lead to the rejection of transplanted tissues and organs.
A type of T-cell that is required by some B-cells to help them make antibodies or that helps other T-cells respond to antigens or secrete lymphokines or interleukins.
Antigen receptors on a T-cell. Unlike antibodies, T-cell receptors are never produced in a secreted form.
A type of lymphocyte responsible for cell-mediated immunity that differentiates under the influence of the thymus.
A foreign macromolecule that does not belong to the host organism and that elicits an immune response.
Nonspecific Immune System Cells
Immune system that does not differentiate between one infectious agent and another. Has two lines- internal and external.
An agranular leukocyte that is able to migrate into tissues and transform into a macrophage.
A type of lymphocye that develops in the bone marrow and later produces antibodies, which mediate humoral immunity.
The type of immunity that fights bacteria and viruses in body fluids with antibodies that circulate in blood plasma and lymph, fluids formerly called humors.
Cell Mediated Response
The type of immunity that functions in defense against fungi, protists, bacteria, and viruses inside host cells and against tissue transplants, with highly specialized cells that circulate in the blood and lymphoid tissue.
A protein secreted by a cytotoxic T-cell that lyse (ruptures) an infected cell by perforting its membrane.
A cytokine secreted by a macrophage that is in the process of phagocytizing and presenting antigen. It in combination with the antigen, activates the helper T cell to produce IL2 and other cytokines.
A cytokine that helps B cells that have contacted antigen differentiate into antibody-secreting plasma cells
Antigen Presenting Cells
Cells that ingest bacteria and viruses and then destroy them. Class II MHC molecules in these cells collect peptide remnants of this degradation and present them to helper cells.
Primary Immune Response
The initial immune response to an antigen, which appears after a lag of several days.
Secondary Immune Response
The immune response elicited when an animal encounters the same antigen at some later time. This is more rapid, of greater magnitude, and of longer duration than the primary immune response.
An antigen-binding immunoglobulin, produced by B cells, that functions as the effector in an immune response.
Molecules that set the body's thermostat to a higher temperature. They are released by certain leukocytes.
A substance released B injured cells that causes blood vessels to dilate during an inflammatory response.
A vertebrate body cell that produces histamine and other molecules that trigger the inflammatory response.
A line of defense triggered by penetration of the skin or mucous membranes, in which small blood vessels in the vicinity of an injury dilate and become leakier, enhancing the infiltration of leukocytes; may also be widespread in the body.
The most abundant type of leukocyte. They tend to self-destruct as they destroy foreign invaders, limiting their life span to but a few days.