immune response

immune response

1) phagocyotosis

phagocyte recognise foreign antigens on pathogen

cytoplasm moves around pathogen engulfing it - pathogen in a phagocytic vacuole

lysome fuses with vacuole. the lysozymes break down pathogen

phagocyte presents pathogens antigens on its surface to active other immune cells

phagocytes activate T-cells

2) T cells, white blood cell. has receptor proteins, bind to complementaty antigens presented on phagocyte

activates T cell

helper T-cells release chemicals that activate ....

...cytotoxic T cells kill abnormal and foreign

... B cells ( white blood cell) covered in antibodies, which bind to antigens and form complexes

b cell antibodies bind to complementary shaped antigen

activates B-cell to divide into plasma cells

clonal selection

plasma cells = clones of B-cells. they secrete many antibodies specific to the antigen - MONOCLONAL ANTIBODIES

they bind to antigens on pathogens - form lots of antigen-antibody complexes

antibody has 2 binding sites = bind to 2 pathogens at same time, clump together - AGGLUTINATION

phagocytes come and engulf/phagocytose many pathogens at once

antibodies = proteins made of amino acid chains. variable region of each is unique with tertiarty structure, making its shape difference - due to diff chain iof amino acids. variable bind region = complementary to specific antigen. the rest of antibody is all the same/constant.

cellular immune response = T-cells and phagocytes

humoral = B-cells, clonal selection, monoclonal antibodies

after exposure to antigen (primary immune response), T - cells & B-cells produce memory cells which remain in body for long time. Tcells remember the specific antigen, Bcells remember specific antibodies needed to bind to antigen.

person is immune - immune system has ability to respond quickly to second infection

secondary immune response

same pathogen enters body again. immune system produces QUICKER, STRONGER response.

secondary response gets rid of pathogen before you begin to show symptoms - immunity