Multidirectional effect of MIF and sodium polyprenyl phosphate on the course of experimental flavivirus infection in mice

AIM: Study of macrophage migration inhibiting factor (MIF) effect after intracerebral administration on the course of experimental infection induced in mice by tick borne encephalitis virus (TEV), and study of sodium polyprenyl phosphate (PPP) and/or antibodies against MIF on the course of this infection against the background of MIF administration. MATERIALS AND METHODS: Phosprenil preparation was used as a source of PPP. PPP was administered intracerebrally. MIF--human recombinant (R&D, USA), mice--Balb/c line. RESULTS: In the sera of mice infected with TEV, MIF production stimulation was detected at days 8 through 10 after the infection--against the background of clinical signs presentation of tick borne encephalitis (TE). Administration of PPP to infected mice, on the contrary, resulted in MIF production suppression at the specified period. After administration of 20 ng of MIF to mice, lethality increased by 40% and average life span decreased by 2.3 days. Thus, MIF at high doses caused an increase of infection course severity, induced by TEV in mice, and administration of 60 microg of PPP resulted in the protection from infection in 100% of cases. Intracerebral administrationto mice of antibodies against MIF resulted in a decrease of lethality indicator up to 26% as compared with control and an increase of averagelife span by 5.5 days. During simultaneous administration into the brain of infected mice of MIF, PPP and antibodies against MIF, prevention of MIF-induced increase of TE course severity was registered. CONCLUSION: The data obtained allow to conclude that MIF may serve as an indicator of TE course severity, and possible prognostic indicator of meningo-encephalitic form development in humans.