Abstract A strong immunomodulatory effect of 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate (MEC) responsible
for the survival of bacteria was shown on isolated macrophages and in experimental infections in mice
(typhoid and tularemia). Derivatives of MEC were found by 1H-NMR spectroscopy under stress conditions in
colorless mutants of the bacteria and isolated to be subsequently purified and used for modulation of the
immune system of animals.
