- Describe cellular and humoral immune responses.
- How are they different from each other?
- Give examples of diseases that compromise each of these responses. Your examples must include how each disease compromises the response
Cellular immune responses generally refer to those that take place inside a cell. Humoral responses take place in the blood or other extracellular fluids.
Cellular responses include self-destruction in the event of overwhelming infection (apoptosis), signaling to other cells that an infectious agent is present, and consumption and digestion/destruction of the infectious agent via macrophages.
Humoral responses are focused on the production of antibodies, proteins which are custom-built to specific infectious agents, bonding with and neutralizing them.
Antibodies are acquired through immunization or infection, assuming the immune system is healthy. Cellular responses generally do not target specific infectious agents, but all agents which are identified as foreign.
Antibodies are coded to a specific "marker" on an infectious agent, called the antigen. Malaria compromises the antibody response by using the var gene to produce a variety of antigens, ensuring that no single antibody will be capable of responding to the entire infection.
Cancer can compromise the cellular response by inhibiting apoptosis, resulting in cells that live far longer than they should. This is somewhat contradictory to the popular conception of cancer as being a matter of runaway mitosis.