# Molecular determinants driving diverse mechanisms of antibody-mediated pathology

> **NIH NIH R21** · YALE UNIVERSITY · 2021 · $251,250

## Abstract

Project Summary. Myasthenia gravis (MG) is an autoimmune disorder of neuromuscular transmission. The
most common subtype is characterized by autoantibodies (autoAbs) targeting the acetylcholine receptor (AChR),
a membrane channel expressed on the muscle end-plate at the neuromuscular junction. The pathology is directly
due to the AChR autoAbs. The AChR autoAbs in the serum of patients are broadly heterogeneous in their
specificity as it includes autoAbs that recognize each of the four different subunits (a, b, e or d) of AChR.
Furthermore, AChR autoAbs can use three distinct mechanisms to effect pathology: (i) complement-directed
tissue damage, (ii) blocking the binding site for acetylcholine and (iii) modulation (internalization) of the AChR.
 Although AChR autoAbs are pathogenic, titers vary widely between different patients and within individuals
during the course of their disease; importantly, titer neither correlates well with clinical severity nor predicts
treatment outcome. Furthermore, new biological therapeutic strategies that specifically target AChR autoAb
complement activation or reduce circulating titers have shown wide variability in response including patients that
do not respond. The disassociation between titer and disease severity, and the heterogeneous response to
autoantibody targeting treatments are not well understood. This gap in our knowledge exists first because AChR
autoAbs are often studied with patient serum, which are confounded by the complex mixture of specificities.
Second, existing assays only measure AChR autoAb binding, but not their pathogenic capacity or mechanism.
We will address these gaps in our knowledge by (i) generating rare human monoclonal AChR autoAbs, (ii)
using novel approaches to measure the different mechanisms of autoAb pathogenicity, and (iii) associating the
autoAb properties with pathogenic capacity. To this end, we applied an unbiased high-throughput approach for
producing AChR-specific human mAbs by cloning B cells, which circumvented technical challenges associated
with cloning mAbs targeting this multi-subunit membrane channel. This will afford production of an AChR specific
mAb library, which includes mAbs that recognize different subunits and epitopes within those subunits. New
approaches to study the different effector mechanisms of AChR autoAb pathogenicity have also been developed.
We will measure AChR autoAb-mediated acetylcholine blocking and AChR modulating functions of the AChR
mAbs. Importantly, an assay for measuring complement activation, in which the complement inhibitors (CD46,
CD55 and CD59) are knocked out, will be used to test AChR autoAb-dependent complement activity. These
experiments will define how the specificity and molecular properties of AChR autoAb are associated with
pathogenic effector function. Overall, this investigation will (i) provide a set of well-characterized mAbs which will
serve as tools for more accurate modeling of AChR autoAb pathology; (ii) provide...

## Key facts

- **NIH application ID:** 10312209
- **Project number:** 1R21AI164590-01
- **Recipient organization:** YALE UNIVERSITY
- **Principal Investigator:** Kevin C O'Connor
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $251,250
- **Award type:** 1
- **Project period:** 2021-07-20 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10312209

## Citation

> US National Institutes of Health, RePORTER application 10312209, Molecular determinants driving diverse mechanisms of antibody-mediated pathology (1R21AI164590-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10312209. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*