Lysis immunity

Complement induced immune lysis of cells and liposomes to release markers which are then detected electrochemically has been used to detect antibodies and antigens in a homogeneous format at nanomolar levels 252-256) qqjJj amperometric and potentio-metric electrodes have been employed. Unfortunately, major improvements in sensitivity appear unlikely, and instability of liposomes makes development of stable reagents for commercial systems difficult. 

The primary function of the B lymphocytes is to produce antibodies, which are molecules that identify and lead to the destruction of foreign substances such as bacteria. The B lymphocytes and the antibodies they produce are responsible for humoral immunity. T lymphocytes provide immunity against viruses and cancer cells. These lymphocytes directly attack and destroy their targets by forming holes in the target cell membrane, causing cell lysis. The T lymphocytes are responsible for cell-mediated immunity. 

The immune complexes (beads) are washed 3 times with lysis buffer, and then 20 /il of 1 x SDS-PAGE sample buffer are added and the samples boiled for 5 min. The supernatant is subjected to SDS-PAGE, followed by western blotting. 

Complement fixation Serum Critical component of humoral immune response leading to lysis of cell membranes, chemotaxis, and phagocytosis... 

Complement A term originally used to refer to the heat-labile factor in serum that causes immune cytolysis, the lysis of antibody-coated cells, and now referring to the entire functionally related system comprising at least 20 distinct serum proteins that is the effector not only of immune cytolysis but also of other biologic functions. Complement activation occurs by two different sequences, the classic and alternative pathways. The proteins of the classic pathway are termed components of complement and are designated by the symbols... 

M. Umeda, Y. Ishimori, K. Yoshikawa, M. Takada, andT. Yasuda, Liposome immune lysis assay (LILA), J. Immunol. Methods 95, 15-21 (1986). 

C3b immune adherence to platelets with release of factor 3 C5b attaches to platelets to cause lysis with release of... 

Figure 17.23 Killing by antibodies and complement working together. Antibodies form a complex with bacteria. The anti-body-bacterium complex can stimulate phagocytosis by macrophages, directly. The complex also activates complement, which stimulates phagocytosis or causes lysis and hence death of bacteria. Activated complex can also lead to inflammation which attracts other immune cells to the site of infection (see Figure 17.24).

Anti-thymocyte globulin (ATG) is a purified immunoglobulin from horse, rabbit, sheep, or goat serum after immunization with human thymocytes. The administration of anti-thymocyte globulin results in a depletion of T-cells as a result of complement dependent lysis and opsonization by the macrophage-monocyte system. The depletion of CD4 positive cells is long lasting and results in an inversion of the CD4/CD8 ratio. There are hardly... 

Conditions which can affect the immune system and cause it to malfunction are Cushing s disease (caused by excess steroid production or treatment - T and B cell lysis), Hodgkin s disease (cancer of the lymph nodes - whole body T cell deficiency), Bruton s disease (B cell deficiency -susceptibility to infection), and, of course, AIDS (Acquired Immune Deficiency Syndrome). 

IgG or IgM antibodies direct the immune response toward the antigen located on a cell (e.g., a red blood cell or thrombocyte). Macrophages, NK cells, and neutrophils are recruited by the antibodies to the site of the antigen on the cell surface and destroy the cell by phagocytosis or lysis. Additionally, complement activation will damage the cell (Fig. 6.32). The result, for example, where red cells are the targets is hemolytic anemia. 

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