Monocyte Activating Factor Originally Found in Sarcoidosis Sera

Abstract

The culture medium of a human acute monocytic leukemia cell line (THP-1)was able to induce normal human monocytes to spread. No such ability was found either in the culture medium of a pro myelocyticleukemia cell line (HL-60) nor in that of a diploid human fibroblast cell line (Flow 7000). Gel filtration of the culture medium of THP-1 cells on a size exclusion column (TSKgel G3000SW) revealed that the most obvious monocyte spreading activity was found in the fraction eluted at the position with a molecular weight of about 70,000. This fraction was also able to increase production of angiotensin converting enzyme and Fc receptor sites for IgG on normal human monocytes.

Effect of Human Fibroblast Interferon on Normal Human Monocyte Activation Induced by a Factor Found in Sarcoidosis Sera

“…Spreading of normal human monocytes was induced by the activating factor in a manner similar to that in our previous study (1). As a control, the cells were incubated with the control factor instead of the activating factor.…”

“…The factor was also able to increase phagocytosis and glucose consumption of normal human monocytes as well as their cell size (1). Thus, we considered this factor to be a monocyte activating factor (1). We also demonstrated that it was a product of mononuclear phagocytes (4).…”

“…The monocyte activatingfactor ofsarcoidosis sera Gel filtration of sarcoidosis sera on Sephadex G-200 revealed that the fraction eluted at the position with about 70',000 molecular weight had the most obvious monocyte spreading activity (1). This fraction was able to increase phagocytosis and glucose consumption of normal human monocytes as well as their cell size (1).…”

“…In our previous study, we demonstrated that sarcoidosis sera contains a factor which induces normal human monocytes to spread (1) as well as another which aggregates normal human monocytes (2). Spreading of mononuclear phagocytes is viewed· as a morphological expression of their activation (3).…”

“…Spreading of mononuclear phagocytes is viewed· as a morphological expression of their activation (3). The factor was also able to increase phagocytosis and glucose consumption of normal human monocytes as well as their cell size (1). Thus, we considered this factor to be a monocyte activating factor (1).…”