immunity and antibodies

• Phagocytosis releases a histamine and attracts phagocytes.
• Phagocytes engulf the pathogen, trap it in a vacuole, and the vacuole fuses to a lysosome.
• The lysosomes secretes lysozymes into the vacuole, onto the pathogen.
• The pathogen is digested, molecules within the pathogen are hydrolysed.
• Phagocyte dies and makes pus.
• Immunity is the ability to remain relatively unaffected by disease despite exposure.
• Immunity usually occurs after the first infection.
• Immunity is achieved by the immune system.
• Immune response involves B cells coating pathogens in antibodies to flag them to phagocytes.
• Cellular response involves T-cells and other immune cells that they interact with (phagocytes).
• Humoral response involves B-cells, clonal selection and the production of monoclonal antibodies.
• T-cells help activate lymphocytes.
• Lymphocytes are smaller than phagocytes, have a large nucleus that fills most of the cell, are produced in bone marrow before birth, and there are two types - B lymphocytes and T lymphocytes, both needed for immune responses.
• There are 10 million lymphocytes in the blood at any one time, one for each type of pathogen.
• Lymphocytes circulate in the blood stream.
• Specific response involves bacteria in a lymph node, being engulfed by a macrophage, antigen removed from bacteria, presenting antigens in MHC, T cells with correct receptors joining on, T cells reproducing by mitosis to produce clones, clones releasing cytokinesis, cytokinesis activating B cells with correct receptors, B cells dividing by mitosis to make clones, clones differentiating to make plasma cells, plasma cells manufacturing antibodies.
• Antibodies are a type of glycoprotein called an immunoglobulin, made of 4 polypeptide chains (two long and two short) held together by disulphide bridges, the variable region is an antigen binding site that’s specific, the hinge region gives flexibility to bind.
• Antibodies combine with viruses and bacterial toxins, attach to flagella of bacteria making them less active so easier for phagocytes to engulf, agglutinate bacteria reducing chances of spreading throughout the body, punch holes in the cell walls of bacteria causing them to burst when water enters them through osmosis, coat bacteria to make it easier for phagocytes to ingest them, combine with toxins to neutralise them, called antitoxins.
• Agglutination is when antibodies cause pathogens to stick together, this makes it easier for phagocytes to engulf them and prevent toxins from being released
• Antibodies bind to the proteins on viruses to block them from binding to host cells.
• There are proteins on the cell surface membrane that are unique to each individual.