# DIPHTHERIA TOXIN AND ITS RECEPTOR

> **NIH NIH R01** · UT SOUTHWESTERN MEDICAL CENTER · 1993 · $233,815

## Abstract

The overall objective of this grant proposal is to characterize  the
receptor-binding domain- and the receptor-binding site within this
domain - of diphtheria toxin, as well as to characterize fully the
specific diphtheria toxin-binding cell surface protein(s) from highly
toxin-sensitive Vero cells that function as the toxin receptor.

The receptor-binding domain has recently been localized to the carboxyl-
terminal  Mr about 6,000 region of diphtheria toxin by our laboratory.
The receptor-binding site will be localized further by chemical
modifications o specific amino acid residues and by site- directed
mutagenesis. Monoclonal antibodies to the toxin's receptor-binding
domain/site will be prepared and will be employed to produce anti-
idiotypic antibodies; the anti-idiotypic antibodies will then be tested
for their ability to protect Vero Cells from diphtheria toxin-mediated
cytotoxicity and for their ability  to recognize the toxin receptor.
Antibodies to the receptor will be employed to characterize and purify
the receptor, and to investigate the cell surface distribution and
mechanism of internalization of the toxin receptor on Vero cells. The
diphtheria toxin-sensitive mouse cells, recently isolated by
transfection of toxin-resistant mouse L-cells with DNA from Vero cells,
will be employed to clone and sequence   the toxin receptor; the
sequence will be   compared to that of other receptors, in order to
determine the nature of the toxin receptor and/or its homology with
other known receptors.

The results of this proposed project will provide an insight into the
possible nature of the physiological cell surface receptor that
diphtheria toxin utilizes to gain illicit access to the cell cytosol,
will significantly extend our knowledge on toxin:receptor interactions,
and will further our understanding on receptor-mediated internalization
of such macromolecules as growth factors, hormones, and other exotoxins.

## Key facts

- **NIH application ID:** 3126853
- **Project number:** 5R01AI016805-13
- **Recipient organization:** UT SOUTHWESTERN MEDICAL CENTER
- **SAM.gov UEI:** YZJ6DKPM4W63
- **Principal Investigator:** LEON EIDELS
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $233,815
- **Award type:** 5
- **Project period:** 1980-04-01 → 1997-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3126853

## Citation

> US National Institutes of Health, RePORTER application 3126853, DIPHTHERIA TOXIN AND ITS RECEPTOR (5R01AI016805-13). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3126853. Licensed CC0.

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