During inflammation, IL-1 stimulates the activity of monocytes/macrophages and T cells, as well as the invasion of these cells and neutrophils into the site of inflammation via actions on the endothelium. The presence of bioactive IL-1 in testicular IF raises the question why the testicular interstitium is not a chronically inflamed tissue. While numerous mononuclear cells, particularly macrophages and lymphocytes, are present in the normal testis at any time, the lymphocytes that are present are not activated, and neutrophils are not usually observed. It is likely therefore that there are other factors present in the testis environment that oppose the proinflammatory activities of IL-1, and consequently it is not surprising that at higher doses testicular IF opposes the actions of IL-1 in vitro. The cellular origin of this activity remains to be established, but its presence in the testis and biological potency clearly suggest that it is an important mediator of testicular immuno-regulation. buy diabetes drugs
The inhibitory activity has been partially characterized. It is due to a factor (or factors) that completely blocks basal and activated T-cell proliferation in vitro. The activity is reproducible and consistent, and it exerts effects at very low IF concentrations. This activity has an apparently large molecular weight (> 100 000) as evidenced by ultrafiltration data, but lower levels of a smaller activity (putatively 3500-10 000 on ultrafiltration data) were also present. The activity is acid stable, and at least partially heat labile and protease sensitive. Extensive dialysis of the untreated, heat-treated (60°C), or acid-treated IF did not remove the inhibitory activity. These data indicate that the activity is not attributable to any of the small molecular weight factors of testicular origin known to inhibit lymphocyte proliferation in vitro, such as endogenous nucleotides, prostaglandin E, or oxidized polyamines. Moreover, the activity is not affected by hydroxylamine, an inhibitor of poly amine oxidase activity.