Immuno Assgt

Passive immunity is the transfer of active humoral immunity in the form of readymade antibodies, from one individual to another. Passive immunity can occur naturally, when maternal antibodies are transferred to the fetus through the placenta, and can also be induced artificially, when high levels of human (or horse) antibodies specific for a pathogen or toxin are transferred to non-immune individuals. Passive immunization is used when there is a high risk of infection and insufficient time for the body to develop its own immune response, or to reduce the symptoms of ongoing or immunosuppressive diseases.

Naturally acquired passive immunity Maternal passive immunity is a type of naturally acquired passive immunity, and refers to antibody-mediated immunity conveyed to a fetus by its mother during pregnancy. Meternal antibodies (MatAb) are passed through the placenta to the fetus by an FcRn receptor on placental cells. This occurs around the third month of gestation.[2] IgG is the only antibody isotype that can pass through the placenta.[2] Immunization is often required shortly following birth to prevent diseases such as tuberculosis, hepatitis B, polio, and pertussis, however, MatAb can inhibit the induction of protective vaccine responses throughout the first year of life. This effect is usually overcome by secondary responses to booster immunization.[3] Passive immunity is also provided through the transfer of IgA antibodies found in breast milk that are transferred to the gut of the infant, protecting against bacterial infections, until the newborn can synthesize its own antibodies.[4]

Artificially acquired passive immunity see also: Temporarily-induced immunity Artificially acquired passive immunity is a short-term immunization achieved by the transfer of antibodies, which can be administered in several forms; as human or animal blood plasma or serum, as pooled human immunoglobulin for intravenous (IVIG) or intramuscular (IG) use, as high-titer human IVIG or IG from immunized or from donors recovering from the disease, and as monoclonal antibodies (MAb). Passive transfer is used prophylactically in the case of immunodeficiency diseases, such as hypogammaglobulinemia.[5] It is also used in the treatment of several types of acute infection, and to treat poisoning [1] Immunity derived from passive immunization lasts for only a short period of time, and there is also a potential risk for hypersensitivity reactions,

and serum sickness, especially from gamma globulin of non-human origin.[4] Passive immunity provides immediate protection, but the body does not develop memory, therefore the patient is at risk of being infected by the same pathogen later.[4]

Naturally acquired active immunity occurs when the person is exposed to a live pathogen, develops the disease, and becomes immune as a result of the primary immune response. Artificially acquired active immunity can be induced by a vaccine, a substance that contains the antigen. A vaccine stimulates a primary response against the antigen without causing symptoms of the disease. The production of antibodies against a specific agent by the immune system. Active immunity can be acquired in two ways: • •

by contracting an infectious disease -- such as, for example, chickenpox; or by receiving a vaccination usually pe-- such as, for example, against polio.

Active immunity is permanent. The individual is protected from the disease all their life. An organisms resistance to disease or infection, developed because the organisms immune system has produced antibodies after an infection or inoculation. a form of acquired immunity in which the body produces its own antibodies against diseasecausing antigens. When a foreign agent such as a virus or bacteria enters the body, the defensive mechanism starts coding for relevant antibodies to remove such foreign agents. this is known as active immunity, as opposed to passive immunity. Active immunity is when a vaccines triggers the immune system to produce antibodies against the disease as though the body had been infected with it. This also teaches the body's immune system how to produce the appropriate antibodies quickly. If the immunized person then comes into contact with the disease itself, their immune system will recognize it and immediately produce the antibodies needed to fight it.