Format

Send to

Choose Destination
See comment in PubMed Commons below
Protein Sci. 2009 Jun;18(6):1210-20. doi: 10.1002/pro.130.

Listeriolysin O as cytotoxic component of an immunotoxin.

Author information

1
Institute of Biotechnology, Martin-Luther-University, Halle-Wittenberg, Kurt-Mothes Strasse 3, Halle, Saale, Germany.

Abstract

Monoclonal antibodies (mAbs) have been developed over the past years as promising anticancer therapeutics. The conjugation of tumor specific mAbs with cytotoxic molecules has been shown to improve their efficacy dramatically. These bifunctional immunotoxins, consisting of covalently linked antibodies and protein toxins, possess considerable potential in cancer therapy. Many of them are under investigation in clinical trials. As a result of general interest in new toxic components, we describe here the suitability of the bacterial protein Listeriolysin O (LLO) as cytotoxic component of an immunotoxin. Unique characteristics of LLO, such as its acidic pH optimum and the possibility to regulate the cytolytic activity by cysteine-oxidation, make LLO an interesting toxophore. Oxidized LLO shows a substantially decreased cytolytic activity when compared with the reduced protein as analyzed by hemolysis. Both oxidized and reduced LLO exhibit a cell-type-unspecific toxicity in cell culture with a significantly higher toxicity of reduced LLO. For cell-type-specific targeting of LLO to tumor cells, LLO was coupled to the dsFv fragment of the monoclonal antibody B3, which recognizes the tumor-antigen Lewis Y. The coupling of LLO to dsFv-B3 was performed via cysteine-containing polyionic fusion peptides that act as a specific heterodimerization motif. The novel immunotoxin B3-LLO could be shown to specifically eliminate antigen positive MCF7 cells with an EC(50) value of 2.3 nM, whereas antigen negative cell lines were 80- to 250-fold less sensitive towards B3-LLO.

PMID:
19472336
PMCID:
PMC2774431
DOI:
10.1002/pro.130
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments

    Supplemental Content

    Full text links

    Icon for Wiley Icon for PubMed Central
    Loading ...
    Support Center