<prompt> Type I helper cells secrete:Interleukin-lInterleukin-2Interleukin-4Interleukin-5  <response>: IL -2 Interleukins are cytokines. Proteins of usually low molecular weight. Regulating important biological processes. Interleukins are produced by Monocytes, Macrophages, B and T Lymphocytes, mast cells, neutrophils. IL1 causes feverIL2 T cell stimulationIL3 Bone Marrow stimulationIL4 IgE StimulationIL5 IgA Stimulation 