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Recombinant human tumor necrosis factor alpha lacks chemotactic activity for human peripheral blood neutrophils and
U Mrowietz1, J M Schröder, E Christophers
1Department of Dermatology, University of Kiel, Fed. Rep. of Germany.
Abstract:
Preparations of recombinant human tumor necrosis factor alpha (rhuTNF alpha) free of aminoterminal methionine were tested for human neutrophil granulocyte (PMN) and monocyte (MO) chemotactic activity using the Boyden chamber system. Over a wide range of concentrations (10(-7)-10(-15) M) rhuTNF alpha of two different sources failed to elicit chemotactic responses in PMN or MO, whereas strong PMN and MO chemotactic activity could be detected using the tripeptide N-formyl-methionyl-leucyl-phenylalanine (FMLP). In addition, rhuTNF alpha containing 62% aminoterminal methionine failed to induce PMN and MO chemotaxis. It is concluded that rhuTNF alpha may not be a chemotaxin for human PMN and MO in vitro.
Insights
Recombinant human tumor necrosis factor alpha (rhuTNF alpha) did not attract human neutrophils (PMN) or monocytes (MO) in laboratory tests. These findings suggest rhuTNF alpha is not a chemoattractant for these immune cells.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Tumor necrosis factor alpha (TNF alpha) is a key inflammatory cytokine.
- The role of TNF alpha in immune cell migration requires further clarification.
- Aminoterminal methionine is a common feature in recombinant proteins.
Purpose of the Study:
- To investigate the chemotactic potential of recombinant human tumor necrosis factor alpha (rhuTNF alpha) for human neutrophils (PMN) and monocytes (MO).
- To determine if the presence of aminoterminal methionine affects the chemotactic activity of rhuTNF alpha.
Main Methods:
- Utilized the Boyden chamber system to assess chemotaxis.
- Tested rhuTNF alpha preparations free of aminoterminal methionine and those containing it.
- Used N-formyl-methionyl-leucyl-phenylalanine (FMLP) as a positive control for chemotaxis.
Main Results:
- rhuTNF alpha, across a broad concentration range (10(-7)-10(-15) M), did not induce chemotaxis in human PMN or MO.
- FMLP demonstrated significant PMN and MO chemotactic activity, validating the assay.
- rhuTNF alpha containing 62% aminoterminal methionine also failed to induce PMN and MO chemotaxis.
Conclusions:
- rhuTNF alpha, in the tested preparations, does not function as a chemoattractant for human PMN and MO in vitro.
- The absence or presence of aminoterminal methionine did not confer chemotactic activity to rhuTNF alpha in this study.