Rabu, 20 Maret 2013

Process of antigen presentation

Process of antigen presentation

Route of antigen entry, capture and presentation in vivo

1) Killer T-cells
    These cells attack the antigens directly and destroy them.
2) Helper T-cells: 
     these cells stimulate the B-cells to produce more antibodies.
3) Suppressor T-cells:  
      These cells suppress the entire immune system so that the latter does not attack the body’s own cells.
4) Memory cells: 
    These cells undergo only limited differentiation after a first exposure to an antigen.They are stimulated into activity on subsequent entry of the same antigen into the body. 

             Interferon is a protein produced and released in small quantities when the cells are invaded by virus and it is effective in inhibiting the viral growth. It is effective against a wide range of viruses.

     The immune system works with amazing complexity. When a B cell encounters a foreign invader, it starts to produce immunoglobulins, or antibodies. Like a key designed to fit only a specific lock, an antibody "locks" onto a single type of antigen like an identifying marker.

     Once the antibody attaches to an antigen, one class of T cells called helper T cells alerts other white blood cells to head toward the site, while another class called killer T cells begins to destroy the antigen marked by the antibody. At the same time, millions of antibodies swarm through the bloodstream to attach to any more of that type of antigen and mount a larger attack.

     The immune system also includes other proteins and chemicals that assist antibodies and T cells in their work. Among them are chemicals that alert phagocytes to the site of the infection. The complement system, a group of proteins that normally float freely in the blood, move toward infections, where they combine to help destroy microorganisms and foreign particles. They do this by changing the surface of bacteria or other microorganisms, causing them to die. 

Types of Immunity

   Immunity may be natural or acquired. Natural immunity is also called inborn immunity which means resistance to a disease is there in the body since birth. But acquired immunity develops in the body after the entry of disease causing pathogens.

    This is a disorder in the defence mechanism of the body, because the antibody produced in this process may act against the products of the own body tissue, treating them as foreign materials.

Immuno deficiency: 
    It means a deficiency in the immune response by the body due to decreased number of less active lymphoid cells, or even in some, where there is complete absence of these cells. Individuals with such deficiency are highly susceptible to even minor infections.

Sumber : Bpk. Dr. Iskandar Zulkarnain

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    ahmad baihaqi
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