The gamma varieties are made by lymphocytes after antigen stimulation and are also called interleukins.  
These cytokines were first recognized in 1957 by Alick Isaacs and Jean Lindenmann.  The beta, or fibroblast varieties, are made by skin cells; white blood cells make the alpha varieties. The gamma varieties are made by lymphocytes after antigen stimulation and are also called interleukins.  For ten points, what class of compounds inhibits the transcription of viral nucleic acid, thus giving them their name.
These cytokines were first recognized in 1957 by Alick Isaacs and Jean Lindenmann.  
interferons