Humoral antigen-antibody

Not all antigen-antibody reactions are of benefit to the body, as sometimes the complexes (or their subsequent interaction with body tissues) may result in tissue damage. This must be regarded as a malfunction of the immune system and is known as a hypersensitive reaction. These reactions can be categorized into five main types. The first three involve the interaction between antigen and humoral antibody, and as the onset of the reaction is rapid, the condition is termed immediate hypersensitivity. The fourth type (delayed hypersensitivity) involves T cells and the symptoms of the reaction appear after 24 hours. The fifth type is where antibody stimulates cell function. 

The protozoa can elicit humoral responses in which antigen-antibody complexes are formed and these can trigger coagulation and complement systems. Immune complexes have been found circulating in serum and deposited in the kidneys where they may contribute to conditions such as glomerulonephri-... 

Antibody-Mediated Immunity (Humoral Immunity) This is the production of antibodies by B lymphocytes to neutralize and destroy an antigen. Antibodies are created in response to sufficient exposure to the antigen through an invasion by the antigen or a vaccination. A vaccination contains small amounts of the antigen sufficient to trigger the immune system to create antibodies. 

Complement system. A group of serum proteins with the capacity to interact with each other when activated. The chain reaction of the activated complement components results in formation of a lytic complex and several biologically active peptides of low molecular weight (anaphylatoxins). The system can be activated by antigen-antibody complexes (classical pathway) and by other components, e.g. bacteria (alternative pathway). As an effector mechanism of the humoral immune response, the activated complement system facilitates opsonization, phagocytosis, and lysis of cellular antigens. Some defects in components of complement are associated with autoimmune diseases (see complement deficiency). 

In the 1980s, further studies expanded our knowledge of the immune response elicited by beryllium. Beryllium appears to evoke a cell-mediated immune response and not a humoral or antibody-mediated immune response. Only a single report has documented the presence of IgG antibodies to beryllium [20]. However, it is not certain as to whether beryllium can cause the production of these antibodies or whether these antibodies were generated by contact with some other antigen and are really only cross-reacting to beryllium. 

Sensitization and Irritation ISO 10993-10 are two more test that are required under ISO 10993-1. Sensitization or hypersensitivity reactions usually occur as a result of repeated or prolonged contact with a chemical substance that interacts with the body s immune system. Because most such reactions to biomaterials have been of the dermal cell-mediated type, rather than the humoral or antigen-antibody type, the skin of laboratory animals is used in sensitivity testing. Dermal sensitization reactions are marked by redness and swelling. The guinea pig, a species known to be nearly as responsive to dermal sensitizers as human beings are used in the sensitization test. 

The clinical relevance of this finding was suggested by the observation that mice were more susceptible to sepsis following infection with Streptococcus pneumoniae when basophils were depleted before the second vaccination with pneumoccocal antigen [22]. Antigen-specific IgG antibodies produced after the second vaccination were significantly lower in the basophil-depleted mice than in control mice. Thus, basophils are important contributors to humoral memory immune responses. 

---