Covalent binding to α-macroglobulins of a protein with free SH groups produced by activated B cells: Blocking by d-penicillamine and gold compounds

Schlesinger, Christa; McEntire, John E.; J, Wallman; Jl, Skosey; Wc, Hanly; Teodorescu, M.

doi:10.1016/0161-5890(89)90079-5

Cited by 4 publications

(5 citation statements)

References 30 publications

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“…Analogous sulfhydryl-exchange processes have been described in the formation of high-molecular-mass aggregates between RTA or RTA-containing immunotoxins and -SH groups bearing a2-macroglobulin molecules in vivo [49]. Among the proteins of the serum HSA has at least one free -SH group [50] that may become available for sulfydryl-exchange mechanisms ; likewise, the human B lymphocyte product LyP can be found disulfide-bonded with a2-macroglobulin [51] and interleukin-lp binds FaZmacroglobulin with an analogous type of interaction [52]. Monensin is soluble in organic solvents (e.g.…”

Section: Discussionmentioning

confidence: 99%

Mechanisms involved in serum‐dependent inactivation of the immunotoxin enhancers monensin and carrier‐protein—monensin

Franceschi

Dosio

Anselmi

et al. 1994

European Journal of Biochemistry

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The immunotoxin-enhancing properties of monensin and of human-serum-albumin-monensin conjugates are severely impaired in the presence of human serum. In this study we have therefore investigated the interaction between serum proteins and monensin leading to the inactivation of monensin function as immunotoxin potentiator. We found that the binding of monensin-specific mAb to thioether-cross-linked or disulfide-cross-linked protein-monensin conjugates is negatively affected by serum, as indicated by immunoenzymic (ELISA) and radioimmunobinding analysis. Size-exclusion chromatography of serum samples indicated that the greatest blocking effect is due to protein components of 40-90 kDa eluting as a broad peak (peak 4). Analysis of the proteins contained within peak 4 by ion-exchange chromatography followed by microsequencing revealed that the major components of peak no. 4 were transferrin, human serum albumin and immunoglobulin fragments. Investigations on the nature of the interactions between serum proteins and monensin leading to monensin inactivation were conducted by affinity chromatography of serum on immobilized human-serum-albumin-monensin conjugates, size-exclusion chromatography, SDSPAGE analysis of serum-treated human-serum-albumin-monensin conjugates, and evaluation of the stability of immobilized human-serum-albumin-bound '251-monensin following treatment with serum. Addition of esterase inhibitors (e.g. EDTA, 4-nitrophenyl phosphate) or prior treatment of the serum at 56°C partially reversed the serum effects observed. We conclude that serum proteins block the immunotoxin-enhancing effect of monensin and of human-serum-albumin-monensin conjugates by multiple mechanisms involving hydrophobic and covalent interactions and enzyme-mediated cleavage of protein-bound monensin.Hybrid molecules formed by mAbAigands chemically or genetically linked to toxins (immunotoxins) have been proposed as a new class of anti-tumor pharmacological reagents [l]. In particular, immunotoxins made with mAb linked to ricin A chain (RTA) have been extensively studied in vitro and in animal models [2-111, and their anti-tumor potential clinically evaluated [ 12-171. Although RTA-immunotoxins show high target-cell selectivity and low in vivo toxicity [12,13,[15][16][17], their cytotoxic potency is variable, depending on the internalization rate [18, 191, the intracellular distribution (11, 20-231, the target-cell type [24, 251 and other parameters. As a result, clinical trials conducted with RTA-immunotoxins have met with limited success [12-171. To increase the anti-target cell potency of RTA-immunotoxins, lysosomotropic amines (e.g. chloroquine, methylamine, ammonium chloride) or ionophores (e.g. monensin,Correspondence to M. Colombatti, Istituto di Immunologia e Malattie Infettive, Universiti di Verona, c/o Policlinico Borgo Roma, 1-37134 Verona, ItalyAbbreviations. HSA, human serum albumin; RIB, radioimmunobinding ; Tfn, transferrin; Nph-P, 4-nitrophenyl phosphate; RTA, rich toxin A chain; SPDP, N-succinimidyl-3-(2-pyridyl...

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Section: Discussionmentioning

confidence: 99%

Mechanisms involved in serum‐dependent inactivation of the immunotoxin enhancers monensin and carrier‐protein—monensin

Franceschi

Dosio

Anselmi

et al. 1994

European Journal of Biochemistry

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“…3 A). Rabbit a 1 M and a 2 M migrate in SDS gels as one band [31]. In addition, the upper band (first from the top) in Fig.…”

Section: Analysis Of the Interaction Of Rhil-8 With Rabbit Ammentioning

confidence: 99%

“…3 human a 2 M or rabbit aM (rabbit a 1 M and a 2 M migrate in SDS gels as one band) that does not penetrate the gel. Rabbit aM or human a 2 M is dissociated into halves by treatment with SDS under non-reducing conditions [31,32]. Incomplete dissociation and/or aggregation will result in generating a moiety which precedes a dimer (half molecule) in the electrophoretic run.…”

Section: Analysis Of the Interaction Of Rhil-8 With Rabbit Ammentioning

confidence: 99%

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Specific binding of IL-8 to rabbit α -macroglobulin modulates IL-8 function in the lung

Kurdowska

Fujisawa

Peterson

et al. 2000

Inflammation Research

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“…Recently a great deal of evidence has been obtained regarding a new important role of a;M as a growth factor binding protein for transforming growth factor -/i [12], nerve growth factor [16], platelet-derived growth factor [4] and interleukin-6 [ 10]. aiM also binds the protein of activated B-lymphocytes [17] and eosinophil eationic protein [15]. These data prompted us to investigate the possible association of Ca-ci>M with some lymphocytederived factors which are probably involved in the above-mentioned immunomodulating effect of Ca-a;M. We have shown [7] that purified Ca-iiM interacts with sheep polyclonal antiserum to the human mononuciear antigen prepared as described by Mendes et al [II].…”

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confidence: 99%

The Complex of α2‐Macroglobulin with CD2 in the Plasma of Gastric Carcinoma Patients

Smorodin¹,

Kurtenkov²

1991

Scand J Immunol

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alpha 2-macroglobulin (alpha 2M) preparations purified from the plasma of healthy persons and gastric carcinoma patients were further analysed by immunochemical techniques. It was found that only alpha 2M from the plasma of gastric carcinoma patients gave a positive reaction with E-receptor sheep antiserum in rocket immunoelectrophoresis. The alpha 2M fraction giving the positive reaction with E-receptor sheep antiserum was isolated and analysed by the immunoblotting technique with monoclonal antibodies to T11 antigen. The presence of the alpha 2M-CD2 complex in the plasma of gastric carcinoma patients was demonstrated. This finding may explain the immunosuppressive effect of the plasma alpha 2M in cancer patients.

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Covalent binding to α-macroglobulins of a protein with free SH groups produced by activated B cells: Blocking by d-penicillamine and gold compounds

Cited by 4 publications

References 30 publications

Mechanisms involved in serum‐dependent inactivation of the immunotoxin enhancers monensin and carrier‐protein—monensin

Mechanisms involved in serum‐dependent inactivation of the immunotoxin enhancers monensin and carrier‐protein—monensin

Specific binding of IL-8 to rabbit α -macroglobulin modulates IL-8 function in the lung

The Complex of α2‐Macroglobulin with CD2 in the Plasma of Gastric Carcinoma Patients

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