Modulee Ten

CONTENT:

Immunity- the ability of the body to resist foreign invaders

2 types of immunity:

Innate Immunity = results from the general and physiological processes

occurring in an individual

Examples of Innate Immunity:

1. Phagocytosis of bacteria– performed by phagocytes

  1. Destruction of swallowed organism by acid secretions and digestive enzymes

    1. Destruction of organisms by some compounds like Lysozyme, Complement system, and natural killer lymphocytes

Acquired Immunity= develops unless foreign body invades the individual thru active/passive Immunization

Acquired Immunity can be achieved thru:

A. Active Immunization such as vaccination and recovery from a disease

b.Passive Immunization such as Colostrum Intake, Blood Transfusion (Plasma convalescent transfusion), and Injection of Hyper Immune SERUM.

Acquired Immunity can be possible thru the development of:

Cellular Immunity - formation of activated T lymphocytes or sensitized T cells (T helper cell, Cytotoxic /killer T cell, and Suppressor T cell/ regulatory T cell)

2.. Humoral Immunity- production of antibodies


Antibodies -

are also called immunoglobulins (lg)

substance produced by B lymphocytes and Plasma Cell (considered as the sixth type of wbc)

The antibody is a Y shaped structure having two portion:

The variable portion (light chain part) is responsible for the attachment of antigen while the constant portion (heavy chain part) is responsible for the activation of the compliment system.

Classes of Antibodies (found mostly in the serum):

  1. IgA- Immunoglobulin (commonly found in body secretions like tears and saliva)

  2. IgD-

  3. Ig G= Bivalent Ig (antibodies with two binding site for attachment of antigen); most numerous immunoglobulins present in the serum

  4. IgM= Polyvalent Ig (antibodies with ten binding site ); First response Ig;
    Large Ig

  5. lgE= Bivalent Ig; numerous in cases of allergic and parasitic reactions

Antigens (Ag) - are substances having a molecular weight of more than 8000

were termed "foreign bodies" because they are not normally present in the body

Examples: could be bacteria and viruses

Antigen - "Antibody Reaction" occurs when a certain foreign substance enters the body of an individual. It can lead to the development of antibodies which acts on the antigen in several ways.

* Processes on how an antibody attacks antigen:

• A. Direct attack

  1. Agglutination

  2. Precipitation

  3. Neutralization

  4. Lysis


• Indirect Action thru the action of COMPLEMENT system activation (group of enzymes present in the body) that leads to some processes such as:

1. Opsonization and phagocytosis of an antigen

  1. Lysis- rupture of an antigen

  2. Agglutination - clumping of cells

  3. Neutralization

  4. Chemotaxis

  5. Activation of mast cells and basophils

  6. Inflammatory reaction