Production of hybridoma growth factor by human monocytes

TLDR

Human mononuclear leukocytes produce a growth factor, HGF, which is identical to IFN‑β2, a 26‑kDa protein, and BSF‑2. HGF production was quantified using a highly sensitive proliferation assay with the B13.29 hybridoma cell line, enabling measurement of single‑cell output. Monocytes, not lymphocytes, produce HGF without stimulation but require serum; bovine serum albumin satisfies this requirement, whereas ovalbumin or human γ‑globulin do not, and production begins after 2 h and completes within 24 h.

Abstract

Abstract Human mononuclear leukocytes produce a growth factor (HGF) for hybridoma and plasmacytoma cells. HGF has recently been proven to be identical to IFN‐β2, 26‐kDa protein and BSF‐2. HGF can be quantitated in a proliferation assay with the HGF‐dependent hybridoma cell line B13.29. By selection of an extremely sensitive variant of this cell line, we were able to measure HGF production of single cells. Limiting dilution analysis of the producing cells in combination with size, density and adherence characteristics showed that HGF is produced by monocytes and not by lymphocytes. There was no need for the monocytes to be stimulated but the cells did require the presence of serum. This serum requirement could be met by purified bovine serum albumin, but not by other proteins like ovalbumin or human γ‐globulin. HGF production in vitro by monocytes starts after 2 h of incubation and is completed within 24 h.