Acquired immunity Acquired immunity Specific or adaptive immune

Acquired immunity

Acquired immunity (Specific or adaptive) immune response The acquired immune response is more specialized than the innate immune response. There are two mechanisms for the acquired immune response: 1 - Humoral immune response. 2 -Cell mediated immune response

Antigen: - It is substance when introduced inside the body, will stimulate specific immune response either in the form of antibodies (Abs) (humoral) or cell mediated immunity produced by T. Lymphocyte. Antibody: - It is serum protein that react specifically with the antigen that produced it Types of antigen (Ag): 1 – Bacterial antigen as cell wall. 2 – Viral, fungal or parasitic antigen. 3 - Human antigen as blood groups. 4 – Drugs. 5 – Food as proteins of milk.

Humoral immunity is mediated by antibodies synthesized by B Lymphocytes and secreted against bacteria and organisms live in the blood (extracellular), immune response are developed in the first exposure differ from the secondary immune response as a result to exposure to the same antigen. Biological function of Immunoglobulins: 1 - Opsonization (get rid of antigen). 2 - Complement activation. 3 - Local immunity. 4 - Agglutination 5 -Neutralization

Cell mediated immune response: involves the production of cytotoxic T cells , cytokines , macrophages , occur in response to infection by intracellular organisms like viruses Functions: 1 - kiliing of intracellular infectious agents 2 -production of cytokines with its effects 3 -resist fungal and parasitic infections.

BUT , it may has harmful effects as in hypersensetivity and autoimmune diseases. Subtypes of T cells: 1 -T Cytotoxic cells : act againest virus, fungi, bacteria, tumors. 2 -T Helper cells : 2 subsets : Th 1 that helps cell mediated immunity, Th 2 that help B cells in antibody production

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