Immunity

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Cell Mediated Immunity

Macrophages engulf pathogens bearing antigens and the antigens become embedded in the macrophage cell membrane.

Binding sites on T-lymphocytes recognise & bind to the antigen

T-lymphocytes are now activated and multiply rapidly, producing a large clone of identical cells, divided into :

Cytotoxic T-cells which release perforin onto the antigen and destroy it.

Helper T- cells which attract and stimulate macrophages.

Memory T-cells which multiply when a 2nd invasion occurs, quickly producing more T-lymphocytes and destroying the antigen.

Supressor T-cells which low down the response of cytotoxic and helper T-cells.

Antibody Mediated Immunity

Macrophages engulf pathogens & antigens embedded in the cell membrane are recognised by B-lymphocytes.

B-lymphocytes are activated when they attach to antigens via specific binding sites

Activated cells enlarge to form plasma cells and produce antibodies or multiply to form a clone of memory B-cells. Dividing B-cells continue this to produce more.

Antibodies circulate, binding with and destroying material containing the specific antigen.

Any further invasion by the same pathogen quickly triggers the ame events due to the presence of memory cells. These activate quickly, producing plasma cells and vast quantities of antibodies.

Cell Mediated Immunity

Antibody Mediated Immunity