<prompt> All of the following are functions of CD4 helper cells except:Immunogenic memoryProduce ImmunoglobulinsActivate macrophagesActivate cytotoxic cells.  <response>: Immunoglobulins are secreted from the B lymphocytes. however, T helper cells helps the B cells, by activating it and produce into plasma cells. These plasma cells secrete the immunoglobulins. Thus, T helper cells indirectly helps in secretion of immunoglobulins. Ref: Andrew E. Williams, The immune system, In the book, Immunology: Mucosal and Body Surface Defences, USA, Wiley Blackwell Publications, Chapter 1.13; Medical Microbiology By Jawetz , 24th Edition, Page 140; Medical Microbiology By Muray, 6th Edition, Pages 119-20; Review of Microbiology and Immunology, 9th Edition, Page 405 