Oral polymorphonuclear leukocytes (PMN) were obtained from 10 adult donors in good oral health using a method employing repeated mouth rinse collection. Interleukin-1 beta (IL-1 beta) mRNA was detected in freshly obtained cells by blot hybridization of total cellular RNA with a biotin labeled cDNA probe. Supernates from oral PMN placed in culture for 3 hours contained substantial amounts of IL-1 beta measured by ELISA. Significantly greater numbers of PMN and amounts of PMN-derived IL-1 beta were obtained from the same donors 2 hours subsequent to an oral sucrose challenge (3.23 x 10(6) vs. 1.57 x 10(6) mean PMN number, P = 0.004; 59.80 vs. 20.05 mean pg/ml IL-1 beta, P = 0.036, respectively). However, the elevated levels of IL-1 beta were due to the higher cell number rather than to increased production by individual cells. Stimulation of oral PMN with recombinant granulocyte-macrophage colony stimulating factor did not enhance their cytokine production. In most instances. IL-1 beta production by oral PMN was dramatically greater than that of their blood counterparts. These findings suggest that oral PMN are an important source of IL-1 beta, which plays a central role in oral immunity and inflammatory disease states.