Suppression of the production of migration inhibitory factor in humans by tetracycline.

The role of Tc in the suppression of immunity has not been widely evaluated although this antibiotic is often prescribed as a long-term therapy [1]. Sporadic reports have indicated that Tc suppresses cellular immunity [2]. However, no data are available concerning the effects of Tc on lymphokine production, especially in human subjects. Peripheral blood mononuclear cells (2 X 10(6)/ml) were obtained from seven normal volunteers and pulsed with 150 micrograms of con A/ml of medium for 3 hr at 37 C. The procedure was carried out in the presence or absence of Tc in RPMI medium under an atmosphere of 5% CO2. The cells were then pelleted, washed, and resuspended in RPMI medium with or without similar concentrations of Tc. Following incubation for 48 hr, the cells were removed and the supernatant was assayed for MIF activities with the use of guinea pig peritoneal macrophages as indicator cells. A change of greater than or equal to 20% in migration was considered significant [3]. Remarkable inhibition of MIF production was noted in cells obtained from five of seven volunteers in the presence of 3 micrograms and 100 micrograms of Tc/ml. ConA-induced inhibition of migration was almost abolished in cell cultures in the presence of 3 micrograms of Tc/ml. Negative inhibition (accelerated migration) was observed in the presence of 100 micrograms of Tc/ml. Macrophage migration in the presence of 100 micrograms of Tc/ml was greater than the migration of control cells. Thus, it appeared that Tc not only interfered with MIF production but also modulated factors involved in the control of normal cell migration.(ABSTRACT TRUNCATED AT 250 WORDS)