Isolation and Characterisation of a Recombinant Antibody Fragment That Binds NCAM1-Expressing Intervertebral Disc Cells

PLoS ONE, 2013 · DOI: 10.1371/journal.pone.0083678 · Published: December 13, 2013

Pharmacology Spinal Disorders Biomedical

Simple Explanation

This study addresses the problem of intervertebral disc (IVD) degeneration, a major cause of neck and low back pain. The approach involves isolating single-chain antibody fragments (scFvs) that can bind to IVD cells, potentially enabling targeted delivery of therapeutics to degenerated discs. The researchers cloned and expressed a portion of the neural cell adhesion molecule 1 (NCAM1), specifically the most cell-distal domain, and used phage display technology to identify human scFvs that bind to this domain. This allows for more effective targeting of cells within the IVD. The isolated scFv was found to bind cultured rat astrocytes, as well as bovine nucleus pulposus and annulus fibrosus cells. This suggests it could be used to deliver therapeutic agents to NCAM1-expressing cells in degenerated IVDs.

Study Duration

Not specified

Participants

Bovine, rat, and human cells

Evidence Level

In vitro study

Key Findings

1
A human scFv was successfully isolated against the recombinant NCAM1 domain using phage display technology.
2
The isolated scFv (B5) bound cultured rat astrocytes, bovine nucleus pulposus, and annulus fibrosus cells, as demonstrated through immunocytochemical studies.
3
The B5 scFv also labeled cells in bovine spinal cord and IVD sections, and its binding to IVD tissues could be inhibited by the soluble NCAM1-Ig1 domain, confirming specificity.

Research Summary

This study successfully isolated a recombinant antibody fragment (scFv) that binds to NCAM1-expressing cells in the intervertebral disc (IVD). This scFv has potential applications in targeted drug delivery to degenerated IVD. The scFv was isolated using phage display technology against the NCAM1-Ig1 domain and was shown to bind to rat astrocytes, bovine nucleus pulposus, and annulus fibrosus cells. The B5 scFv exhibited significant binding to both six-month old and two-year old bovine IVD tissues, with binding inhibitable by the soluble NCAM1-Ig1 domain, indicating specificity for NCAM1 in these tissues.

Practical Implications

Targeted Drug Delivery

The isolated scFv can be used to specifically deliver therapeutic agents to NCAM1-expressing cells within the degenerated intervertebral disc, potentially improving the efficacy of regenerative treatments.

Cost-Effective Antibody Production

Recombinant antibody fragments offer a more cost-effective and faster alternative to traditional monoclonal antibodies, making them attractive for tissue engineering applications.

Enhanced Tissue Penetration

The smaller size of scFvs compared to whole antibodies allows for better tissue penetration, which is crucial for reaching target cells within the avascular environment of the intervertebral disc.

Study Limitations

1
The study primarily focused on in vitro experiments, and further in vivo studies are needed to confirm the efficacy and safety of the scFv in a living organism.
2
While the scFv showed binding to both nucleus pulposus and annulus fibrosus cells, more detailed investigations of human IVD tissues of different ages and disease grades are required to determine the scFv's binding ability throughout the degenerative cycle.
3
NCAM1 is also expressed on non-IVD cells, which could lead to off-target effects if the scFv is used for systemic drug delivery. Further modifications or targeting strategies may be necessary to enhance specificity.

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