Defective interfering particle
... by themselves. Instead, they depend on coinfection with a suitable helper
virus. The helper
virus provides the gene functions that are absent from the DIPs.
Major histocompatibility complex
... Class II molecules interact exclusively with CD4+ T cells (also known as helper
T cell lymphocytes or HTLs). The helper
T cells then help to trigger an appropriate immune response which may ...
... target cells which express specific antigens that they recognize.
T cells (CD4 + ) are "middlemen" in the immune response. When they get ... HIV infection, and the decrease of CD4 + T cells results in AIDS . Some helper
T cells secrete cytokines that turn off the immune response once an ...
... B cells of the immune system. B cells are activated upon binding to their specific antigen. In some cases the interaction of the B cell with a T helper
cell is also necessary.
Structure of the antibody
Immunoglobulins are heavy plasma proteins, often with added sugar chains (see ...
... cells (APCs), and degraded into fragments. The fragments are then presented on the surface of APCs by class II histocompatibility molecules to T helper
cells (CD4 + ). Those that are specific for them, get activated, so they start to secrete cytokines . The cytokines then activate cytotoxic ...
Helper T cell
... A helper
(or T H ) T cell is a T cell (a type of white blood cell ) which has on its surface antigen receptors that can bind to fragments of antigens ...
... to signal that cell to become apoptotic ("commit suicide"), thus killing that cell and any viruses it is in the process of creating.
T cells (T H cells) activate infected macrophages (cells that ingest dangerous material), and also produce cytokines ( interleukins ) that ...
Memory B cell
... system, they are stored inside the circulatory system for later use, for long periods of time, possibly a whole lifetime.
Like other cells such as helper
T cells , killer T cells , and plasma cells they never become directly involved in the immune response to foreign objects in a living body. If a ...