Preparation and Characterization of Conjugates of Recombinant CD4 and Deglycosylated Ricin A Chain Using Different Cross-Linkers

Victor Ghetie, Mark A. Till, Maria Ana Ghetie, Thomas Tucker, Jim Porter, Eric J. Patzer, James A. Richardson, Jonathan W. Uhr, Ellen S. Vitetta

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

In a previous study, we have demonstrated that conjugates containing soluble, recombinant human CD4 (rCD4) and the deglycosylated form of ricin A chain (dgA) (rCD4-dgA) effectively kill a human T cell line infected with the human immunodeficiency virus (HIV) in vitro. In contrast, such conjugates are 100–1000-fold less toxic to uninfected cells. In order to use a rCD4-dgA conjugate effectively in vivo, it was important to demonstrate that (1) it binds to and kills HIV-infected, but not uninfected, human cells, (2) it is stable in the circulation, and (3) it has an optimal therapeutic index (toxicity to animals versus toxicity to target cells). A major factor affecting the efficacy of such conjugates in vitro and in vivo is the nature of the cross-linker between the ligand (rCD4) and the toxin (dgA). In this report, we have prepared rCD4-dgA conjugates using three different cross-linkers. Different methods of purification have been compared by determining the optimal yield, purity, and retention of biological activity (i.e., binding to gpl20 and dgA chain activity). The structure of these conjugates as well as their cytotoxicity to target cells in vitro has been analyzed. Finally, we have compared their pharmacokinetics, tissue localization, and toxicity in mice.

Original languageEnglish (US)
Pages (from-to)24-31
Number of pages8
JournalBioconjugate Chemistry
Volume1
Issue number1
DOIs
StatePublished - Jan 1 1990

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Biomedical Engineering
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry

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