Ab also blocks attachment of bacteria at mucosal surfaces. Describe the manner in which virally infected cells are recognized by the immune system and are killed. The CTL recognize this with their antigen specific T cell receptor, become activated and kill the cell. Killing is achieved by the release of perforin which pokes holes in the cell and allows entry of Granzyme B. Granzyme B kills the cells by apoptosis. The major preformed mediator of mast cells is histamine.
Histamine also causes vasodilation which results in increased blood flow to the area.
Describe two sites in the development of B cells into class specific antibody secreting plasma cells where problems could result in humoral immune deficiency. This could be caused by a lack of RAG genes so that surface antibody is not produced or from lack of kinases which allow for pre-B cell progression. This would result in CID or agammaglobulinemia. A lack of cytokine mediated class switch to a particular isotype. This can result from the lack of cytokine or cytokine receptors.