Type I helper cells secrete:
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 fever
IL2 T cell stimulation
IL3 Bone Marrow stimulation
IL4 IgE Stimulation
IL5 IgA Stimulation
Interleukin-l
Interleukin-2
Interleukin-4
Interleukin-5