Human Granulosa Cells Express HLA-DR Antigen and are Capable of Synthesizing Interleukin-1

Abstract

To study the origin of interleukin 1 (IL-1) present in human follicular fluid we determined the percentage of macrophages (MO) and cells with HLA-DR antigen (DR+) present in 22 samples of human follicular fluid (FF) from women undergoing in vitro fertilization, and examined the release of IL-1β by cultures of purified human granulosa cells (GC). The number of red blood cells (RBC) in the crude preparation was taken as a measure of possible contamination with peripheral blood monocytes (assuming a ratio of one monocyte or MO per 10⁴ RBC). For the evaluation of MO and DR+ cells percentages we employed an indirect immunofluorescence technique using specific monoclonal antibodies. Total cells from FF were purified by Ficoll-Hypaque density gradient centrifugation (δ = 1.076 g/l and GC were purified using a gradient δ = 1.065 g/l. This method reduced the contamination with MO to 0-1%. The spontaneous release of IL-1β was measured by ELISA. We found that FF contained 9.81 ± 1.47% of MO but only 7.85% were ovarian MO. In addition the total percentage of DR+ cells was 17.13 ± 2.35% but only 9.81% corresponded to MO. Therefore about 7.32% of DR+ cells could be GC. Then purified GC (10⁴/0.2 ml/well) were cultured during 24 hours at 37 °C in serum free medium (DMEM:F12). IL-1β levels were 84±17 pg/ml and these values were increased by 44% when GC were stimulated with FSH (200 ng/ml). These results suggest that GC produced IL-1β and that the synthesis of this cytokine might be regulated by hormones.

Key words

Macrophages - Granulosa Cells - HLA-DR Antigen - Interleukin 1