Open AccessDifferentiation between vascular permeability factor and IL‐2 in lymphocyte supernatants from patients with minimal‐change nephrotic syndrome
Author(s) -
HESLAN J.M. J.,
BRANELLEC A. I.,
PILATTE Y.,
LANG P.,
LAGRUE G.
Publication year - 1991
Publication title -
clinical & experimental immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.329
H-Index - 135
eISSN - 1365-2249
pISSN - 0009-9104
DOI - 10.1111/j.1365-2249.1991.tb05789.x
Subject(s) - lymphokine , biological activity , interleukin 2 , lymphocyte , t lymphocyte , immunology , biology , microbiology and biotechnology , antigen , immune system , in vitro , biochemistry
SUMMARY Immunolherapy of cancers with recombinant IL‐2 induces a vascular leak syndrome which is mainly due to an increase in vascular permeability. A lymphokine, the vascular permeability factor (VPF), which increases vascular permeability, has been characterized in minimal‐change nephrotic syndrome (MCNS) and appeared very similar to IL‐2. Here we have undertaken a further characterization of VPF in order to determine how closely related this factor was to human IL‐2. Both the IL‐2 bioassay and Western blot analysis of the MCNS lymphocyte concentrated supernatants with high VPF activity revealed the presence of low quantities of IL‐2. Preparative isoelectrofocusing (IEF)orconcentratedsupernatanls resolved each lymphokine in a separate peak, with apparent pIs of 5.2 for VPF and 7.5–10. for IL‐2. Since a sensitive IL‐2 ELISA failed to exhibit any significant antigenic presence of IL‐2 in the IEF fractions with the highest VPF activity, we conclude that VPF activity of the concentrated supernatanis is not related to IL‐2 nor to a biologically inactive form of IL‐2. When concentrated supernatants were subjected to preparative SDS‐PAGE, VPF activity was recovered within low mol. wt material (1–12 kD). Immuno‐adsorption experiments gave definite proof since the complete removal of IL‐2 from concentrated supernatants did not affect the VPF activity. Although high amounts of IL‐2 increased vascular permeability, our experiments clearly demonstrate that VPF is a lymphokine distinct from IL‐2.