False-colour transmission electron micrograph (TEM) of the bacterium Escherichia coli, genetically-engineered to produce quantities of human gamma interferon, which appears as the red mass in this section. The interferons are one group of substances (known as lymphokines) that are produced by T- lymphocytes which act to inhibit intracellular viral replication & modulate the proliferation of other cells involved in the immune response. They are believed to be effective against certain infections (hepatitis), autoimmune disease (rheumatoid arthritis) & some cancers. Magnification x28,000 at 6x7cm size.