Opsonization antibody-mediated

IgG Immunoglobulin G is present in lymph fluid, blood, cerebrospinal fluid and peritoneal fluid. It is composed of 2 y chains of 50 kDa and 2 L chains (k or ) of 25 kDa with a total molecular weight of 150 kDa. The functions of IgG include agglutination and formation of precipitate, passage through placenta and thus conferring immunity to fetus, opsonization, antibody-dependent cell-mediated cytotoxicity (ADCC), activation of complement, neutralization of toxins, immobilization of bacteria and neutralization of virus. 

Immunity What the patient does to the pathogen. For example, a patient with AIDS who is exposed to tuberculosis may develop the disease in spite of receiving a course of postexposure prophylactic antituberculosis chemotherapy, which would be effective in a patient with an intact immune system. Immunity includes both nonspecihc complement-mediated opsonization and specihc antibody- and cell-mediated immunity. 

It consists primarily of IgG and contains trace amounts of IgA and IgM. y-Globulin provides the patient with passive immunity and does not require time for the development of an antibody response. It is believed to inhibit viral penetration of host cells, opsonize viral particles, activate complement, and stimulate cell-mediated immunity. 

However, when PMNs were stimulated, not by antibody on the surface of the tumor cell, but instead by Concanavalin Aor by opsonized zymosan myeloperoxidase did appear to mediate the killing azide and cyanide inhibited the killing, halides were required, catalase inhibited, and PMNs from patients with either hereditary deficiency of myeloperoxidase or chronic granulomatous disease were... 

In humans, there are five isotypes of antibodies, IgG, IgA, IgD, IgE, and IgM, which are defined by the structures of their heavy chains and their abilities to form multimers (Figure 10.1) [8], IgG is the most abundant isotype present in serum with average serum concentrations ranging from 0.5 to 9mg/ml depending on the IgG subtype. This is followed by IgA (3mg/ml), IgM (1.5mg/ml), IgE (0.05 mg/ml), and IgD (trace). Each antibody isotype has unique functions. Critical functions of IgG include opsonization, complement activation, antibody-dependent cell-mediated cytotoxicity (ADCC), passive immunity, and regulation of B cells. Both IgM and IgD act as antigen receptors on naive B cells, and soluble, multimeric forms of IgM are involved in complement activation. IgA is involved in mucosal and passive neonatal immunity, while IgE is involved in immediate hypersensitivity [8],... 

Another effector function is the cell-mediated cytotoxicity. Infected cells that were recognized and opsonized by specific antibodies can be lysed by natural killer cells which are the classical K cells. These properties are highly determined by the Fc part of antibodies. IgGl and IgG3 have the highest capacity for cell-mediated cytotoxicity. The effector function of an antibody is frequently used as a mean of antibody recognition. This is especially the case with bacterial proteins such as protein A and protein G that specifically interact with the same domain. Therefore purification can interfere with the antibody effector function. 

---