# Rationalizing glycoengineering strategies for immunotherapeutic antibodies

> **NIH NIH R01** · EMORY UNIVERSITY · 2020 · $501,240

## Abstract

In order to evade host immunity, many bacteria secrete immunomodulatory enzymes. Streptococcus
pyogenes, one of the most common human pathogens, secretes unique endoglycosidases, including EndoS,
which removes complex-type glycans in a highly specific manner from human IgG antibodies, and its homolog
EndoS2, which can additionally remove IgG-linked high-mannose glycans. This renders antibodies incapable
of eliciting host effector functions through either complement or Fc γ receptors (FcγRs), providing the bacteria
with a survival advantage. Because antibodies are central players in many human immune responses and
bridge the innate and adaptive arms of immunity, the analysis and manipulation of the enzymatic activities of
EndoS and EndoS2 impact diverse fields in biomedicine. In particular, modifying antibody glycan structures
can have significant impacts on their abilities to bind to FcγRs and the subsequent immune system reactions
that they induce. The next generation of therapeutic antibodies is already being constructed with modified
glycan chemistries to tailor their immune reactions and to increase their clinical potency. EndoS and EndoS2,
as antibody-specific glycosidases, and glycosynthases derived thereof, are key enzymes in the future of
antibody engineering. We propose that if the molecular mechanisms by which diverse endoglycosidases
specifically recognize and hydrolyze distinct glycoprotein substrates are better understood that EndoS and
EndoS2 variants can be rationally engineered to create a new class of antibody-modifying enzymes endowed
with unique glycan specificities in order to modify antibodies that exhibit enhanced clinical properties. In this
proposal, we will address three Specific Aims: (1) to determine the molecular basis of glycan specificity by
endoglycosidases; (2) to define the role of carbohydrate binding modules – non-enzymatic protein domains
with glycan binding properties – in endoglycosidase specificity and activity; and (3) to elucidate the molecular
basis of protein specificity by endoglycosidases. Progress towards these complementary, yet independent,
Specific Aims will significantly advance our understanding of glycan-modifying enzymes. Leveraging this
knowledge in the context of EndoS and EndoS2 will enhance our ability to customize antibodies, further
unleashing their vast therapeutic utility and expanding their positive impact on human health.

## Key facts

- **NIH application ID:** 9875855
- **Project number:** 1R01AI149297-01
- **Recipient organization:** EMORY UNIVERSITY
- **Principal Investigator:** ERIC JOHN SUNDBERG
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $501,240
- **Award type:** 1
- **Project period:** 2020-04-08 → 2025-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9875855

## Citation

> US National Institutes of Health, RePORTER application 9875855, Rationalizing glycoengineering strategies for immunotherapeutic antibodies (1R01AI149297-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9875855. Licensed CC0.

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