Revise Antibodies and vaccination for Cambridge 9700 (11.2)

Hinge region – gives flexibility to bind around antigen.

Antigen binding sites – sequence of amino acids in these regions make a specific 3D shape which binds to one type of antigen Functions of antibodies.

attach to flagella of bacteria making them less active and easier for phagocytes to engulf.

cause agglutination (clumping together) of bacteria, reducing chances of spread.

punch holes in bacteria cell walls, causing them to burst when they absorb water by osmosis.

antibodies coat bacteria, making phagocytosis easier as phagocytes have receptor proteins.

combine with toxins, neutralising them (antitoxins).

combine with viruses and bacterial toxins, preventing them from entering or damaging cells Hybridoma method for the production of monoclonal antibodies.

B-cells that divide by mitosis do not produce antibodies and plasma cells that secrete antibodies do not divide.

used to locate position of blood clots.

used to locate cancer cells which have different cell surface proteins and therefore can be detected by antibodies.

used to identify exact strain of virus or bacterium causing an infection, which speeds up treatment In treatment.

treatment of breast cancer – antibody binds to cancerous cells and marks them for destruction by immune system.

treatment of rheumatoid arthritis (autoimmune) – antibody binds to proteins secreted by T-cells that causes damage to cartilage in joints and blocks its action Types of immunity Vaccination Vaccines.

preparation containing antigens which is used to stimulate an immune response artificially.

suffer from malnutrition and don’t have enough proteins to make antibodies or clones of lymphocytes.

Active Immunity: Your body actively produces its own antibodies and memory cells in response to an antigen. This leads to long-term protection.

• Natural active immunity: Acquired through direct exposure to a pathogen and subsequent recovery from the infection (e.g., getting chickenpox).

• Artificial active immunity: Acquired through vaccination, where antigens are introduced without causing illness.

Passive Immunity: Your body receives pre-formed antibodies from an external source. This provides immediate but short-lived protection as no memory cells are formed.

• Natural passive immunity: Acquired when antibodies are transferred from mother to child across the placenta or via breast milk.

• Artificial passive immunity: Acquired through the injection of antibodies, often for immediate protection against toxins or venoms (e.g., tetanus antitoxin, antivenom).

Vaccination involves introducing a harmless form of a pathogen (e.g., attenuated live pathogen, killed pathogen, isolated antigens, or toxoids) into the body.

This exposure stimulates a primary immune response, where B cells are activated, differentiate into plasma cells (to produce antibodies), and crucially, form memory B and T cells.

The primary response is typically slower and produces fewer antibodies than a secondary response.

Upon subsequent exposure to the actual pathogen, these memory cells trigger a much faster, stronger, and more prolonged secondary immune response, rapidly producing a high concentration of specific antibodies to neutralise the threat before symptoms develop.

Vaccination not only protects individuals but also contributes to 'herd immunity' within a population. This occurs when a sufficiently large proportion of the community is immune, making it difficult for the disease to spread, thereby protecting those who cannot be vaccinated (e.g., infants, immunocompromised individuals).