<prompt> All of these are antigen presenting cells APCsexcept -a T cellsb B cellsc Fibroblastsd Dendritic cellse Langerhans cellsacbcadb  <response>: T cells cannot be activated by soluble antigens.Therefore, presentation of processed antigen by antigen presenting cells is required for activation of T cell.The initial step in immune response whether humoral or cellular is phagocytosis of the antigen by antigen presenting cells.These antigen presenting cells process and present the antigen to T cells.These activated T cells then interact with B cells in humoral immunity or with other T cells in cell mediated immune response 