PRODUCTION OF INTERLEUKIN-1 FROM MACROPHAGES INCUBATED WITH POLY(DL-LACTIC ACID) GRANULES CONTAINING OVALBUMIN

The production profile of interleukin 1 (IL-1) from mouse peritoneal m acrophages (Mo) was determined following their incubation with poly(DL -lactic acid) (PDLLA) granules containing ovalbumin (OVA). Upon incuba tion, Mo produced IL-1 at a significantly high rate compared with thos e incubated with OVA in the free form or OVA-free granules. A simple m ixture of empty granules and free OVA exhibited the same level of IL-1 production as induced by free OVA alone. IL-1 production by the granu les with a fixed OVA loading increased with an increase in their amoun t added to Mo. When incubated with a fixed amount of granules containi ng OVA of different loadings, MO produced more IL-1 with an increase i n the total OVA amount, but the IL-1 production decreased at OVA loadi ngs higher than 10%. The presence of free OVA enhanced IL-1 production with the increased addition of empty granules, but the level induced by OVA loaded in granules was higher than that by mixtures of free OVA and empty granules, when compared at a similar OVA dose, irrespective of the absolute amount of PDLLA added. These findings indicate that t he sustained release of OVA from the granules is critical to enhance t he OVA-induced IL-1 production, in contrast to the OVA release accompa nying a large initial burst, which reduced IL-1 production. It was con cluded that the direct contact of PDLLA granules with Mo and the subse quent sustained release of OVA around Mo effectively activated Mo, res ulting in enhanced IL-1 production. (C) 1996 Elsevier Science Limited.