Related Experiment Video
Updated: Jun 20, 2026

Fluorescence Assays for the Study of Mycobacterium tuberculosis Interaction with the Immune Receptor SLAMF1
Published on: February 28, 2025
Receptor-mediated and lectin-like activities of carp (Cyprinus carpio) TNF-alpha
Maria Forlenza1, Stefan Magez, Jörn P Scharsack
1Cell Biology and Immunology Group, Wageningen Institute of Animal Sciences, Wageningen University, Wageningen, The Netherlands.
Abstract:
Functional characterization of TNF-alpha in species other than mammalian vertebrates is limited, and TNF-alpha has been studied in a limited number of fish species, primarily in vitro using recombinant proteins. Studies on TNF-alpha from different fish species so far pointed to several inconsistencies, in particular with respect to some receptor-mediated activities of fish TNF-alpha, such as the ability to directly activate phagocytes. In the present study a comprehensive analysis of in vitro as well as in vivo biological activities of two isoforms of carp TNF-alpha was performed. Our results show that carp TNF-alpha directly primes carp phagocytes and indirectly promotes typical receptor-mediated activities such as phagocyte activation by acting via endothelial cells. Additionally, for the first time in nonmammalian vertebrate species, the lectin-like activity of fish TNF-alpha homologs was investigated. Our results show an evolutionary conservation of function of this receptor-independent activity of TNF-alpha not only in cyprinid fish, but also in perciform and salmonid fish. The role of TNF-alpha in vivo, during infections of carp with the blood parasite Trypanoplasma borreli, was examined using three fundamentally different but complementary approaches: (1) inhibition of TNF-alpha expression, (2) overexpression of TNF-alpha, and (3) inhibition of shedding of membrane-bound TNF-alpha. Our results show that, also in fish, a tight regulation of TNF-alpha expression is important, since depletion or excess of TNF-alpha can make an important difference to survival of infection. Finally, we demonstrate a crucial protective role for membrane-bound TNF-alpha, which has a yet unexploited function in fish.
Related Concept Videos
Selectins
Signal Transduction: Overview
Typically, signal transduction involves three...
The JAK-STAT Signaling Pathway
Immunoglobulin-like Cell Adhesion Molecules
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
Transducer Mechanism: Nuclear Receptors
About 48 different soluble family members of nuclear receptors are identified that can be divided into two main classes:
NF-κB-dependent Signaling Pathway
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...

