Immunity

• Humoral response is an adaptive primary response.
• Antibody is a protein which is made by B cells and is specific to one antigen.
• heavy chain and light chain are parts of the antibody.
• Constant region and antigen binding site are parts of the antibody.
• Variable region changes for different antigens.
• Humoral response involves the production of antibodies by B cells.
• Antibody T cloning and secrection are processes in the humoral response.
• B cells divide by mitosis to produce plasma cells, which are responsible for the humoral response.
• Pathogen recognition is a process in the humoral response.
• Helper T cells assist in the humoral response by binding to the antigen on B cells and activating them.
• Clones can produce complementary antibody for specific antigen in the humoral response.
• The humoral response helps in future infections by remembering what the antigen looks like and can recognise them quickly.
• Antibodies destroy pathogens by agglutination, being antitoxins, and marking antigens for phagocytes.
• Antibodies are produced in bone marrow and mature in the thymus.
• Humoral response is responsible for antibody production.
• describe how HIV is replicated

  • Attachment proteins attach to receptors on helper T cell
  • RNA enters cell;
  • Reverse transcriptase converts RNA to DNA;
  • Viral proteins produced;
  • Virus particles assembled and released from cell;
• describe how the human immunodeficieny virus (HIV) is replicated once inside helper T cells

  • RNA converted into DNA using reverse transcriptase;
  • DNA inserted into helper T cells;
  • DNA transcribed into HIV mRNA;
  • HIV mRNA translated into viral proteins for assembly into viral particles
• describe how a phagocyte destroys a pathogen present in the blood

  • Engulfs;
  • Forming vesicle and fuses with lysosome;
  • Enzymes hydrolyse;
• give two tyes of cell other than pathogens that can stimulate an immune response

  • abnormal body cells
  • antigen presenting cells
• what is the role of the disulfide bridge in forming quaternary structure of an antibody

  • join two different polypeptides
• explain how HIV affects the production of antibodies when AIDS develops in person

  • less antibodies produced
  • because HIV destroys helper T cells
  • so few B cells are activated
• determining the genome of the viruses could allow scientists to develop a vaccine. Explain how

  • will allow to identify the proteome
  • could identify potential antigens
• what is a monoclonal antibody?


  antibodies with the same tertiary structure
• describe the role of antibodies in producing a positive result in a ELISA test

  • antibody binds to antigen;
  • antibody with enzyme attached is added;
  • antibody attaches to antigen;
  • solution added and colour changes
• describe how phagocytosis of virus leads to presentation of its antigens

  • vesicles fuses with lysosome
  • Virus destroyed by lysozymes
  • antigen from virus are displayed on cell membrane
• Describe how presentation of a virus antigen leads to the secretion of an antibody against this virus antigen.

  • helper T cells bond to antigen
  • this helper T cell stimulates a specific B cell
  • B cells clone
• what is an antigen?

  a foregin protein that can trigger an immune response
• what is an antibody?

  a protein produced by B cells
• When a vaccine is given to a person, it leads to the production of antibodies against a disease-causing organism. Describe how

  • Vaccine contains antigen from pathogen;
  • Macrophage presents antigen on its surface;
  • T cell with complementary receptor protein binds to antigen;
  • T cell stimulates B cell;
  • complementary antibody on its surface;
  • B cell secretes large amounts of antibody;
  • B cell divides to form clone all secreting same antibody.
• Describe the difference between active and passive immunity.

  • Active involves memory cells, passive does not;
  • Active involves production of antibody by plasma cells
  • Passive involves antibody introduced into body from outside
  • Active long term, because antibody produced in response to antigen;
  • Passive short term, because antibody is broken down;
  • Active take time to develop, passive fast acting.