Adaptive immune response

The adaptive immune response is the stage that follows the innate immune response. The innate immune response comprises of various stages for example inflammation and complement activation. The innate immune response is rapid and occurs as soon as infection occurs. The adaptive immune response on the other hand usually starts a few hours after the onset of infection and can last days or even weeks depending on the severity of the infection. The responses include:

1. Interaction between antigen-presenting dendritic cells and antigen-specific T cells. This triggers a series of responses including the recognition of the antigen and T cell proliferation and differentiation. This response usually occurs a couple of hours after infection and can last days.
2. Activation of antigen-specific B cells. This starts a couple of hours after infection and can last for days.
3. Formation of effector and memory T-cells. This occurs a couple of days after infection and can last for weeks.

After these a cascade of events occur including the formation of effector B cells (plasma cells, differentiate to form required antibodies on infection) and memory B cells. The events above als trigger the migration of Lymphocytes from peripheral lymphoid organs to the area of inflammation. These lymphocytes are able to engulf and digest the pathogen via the fusion of a lysosome, releasing lysozymes, a digestive enzyme used to neutralise the pathogen. Effector cells and antibodies can then go on to eliminate te pathogen. This then leads to a reduction in inflammation and the subsidence of any other side effects caused by infection.