Question

which of the following does not represent the role of a cell marker in the third line of defense

Answer 1

Following cells are involved in third line of defence -

T- cell may be helper or cytotoxic or memory(for secondry immune response) and helper activates other cells of immune system and cytotoxic T- cells are in volved in destruction of self antigens.
Another type of cell involved are B cell which produce two types of cells plasma and memory B cells which produce antibodies in response to an antigen entered in body. These are activated by APC (Dendrites, B cells etc.) or by T helper cells.
Macrophage are also involves i elimination of antigens by phagocytosis and also involved in antibody dependent cell cytotoxicity.