# IMMUNOTOXIN INTERNALIZATION AND PROCESSING

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN DIEGO · 1988 · $145,886

## Abstract

As part of a coordinated program to develop effective, specific,
antibody-ricin (ricini A-chain) conjugates for use in immunotherapy, the
studies described in this proposal seek to: (a) more fully understand the
process of toxin and immunotoxin internalization and degradation by
hematopoietic cells; (b) to characterize further the effects of
lysosomotropic amines and proton ionophores on the cellular processing of
toxins and conjugates; and (c) to produce whole-ricin immunotoxins with
modified ricin moieties which no longer recognize cell-surface terminal
galactose or N-acetylgalactosamine residues.  More specifically we plan to
study the effects of conjugation on antibody binding and affinity, to
characterize the cellular metabolic products of the toxin and antibody
moieties both in the presence and absence of lysosomotropic amines, proton
ionophores, and other potentiating reagents, to characterize the functional
domains of the ricin A- and B-chain polypeptides using anti-peptide
antisera, and to chemically modify the ricin B-chain such that it retains
only its translocation properties.  This work is both timely and important.
Timely because of the currently intense evaluation of immunotoxins as
immunotherapeutic reagents, and important because of the as yet poorly
understood characteristics which comprise an effective immunotoxin.  Only
when the significance of these characteristics is fully appreciated will
truly effective immunotoxins be available for use in chemotherapeutic
protocols.

## Key facts

- **NIH application ID:** 3173295
- **Project number:** 5R01CA035692-06
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN DIEGO
- **SAM.gov UEI:** UYTTZT6G9DT1
- **Principal Investigator:** RAYMOND M TAETLE
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $145,886
- **Award type:** 5
- **Project period:** 1983-07-18 → 1990-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3173295

## Citation

> US National Institutes of Health, RePORTER application 3173295, IMMUNOTOXIN INTERNALIZATION AND PROCESSING (5R01CA035692-06). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3173295. Licensed CC0.

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