# Identification of Recombinant Adeno-Associated Virus Serotypes by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

## TL;DR

This paper introduces a new method using MALDI–MS to identify rAAV serotypes, offering a faster, cheaper, and reagent-free alternative to traditional techniques.

## Contribution

A novel MALDI–MS method with a new scoring algorithm for rapid and reagent-free rAAV serotype identification.

## Key findings

- The MALDI–MS method can distinguish multiple rAAV serotypes, including mutants, using peptide mass fingerprints.
- The approach eliminates the need for antibodies and reduces sample preparation, enabling high-throughput screening.
- The method is cost-effective and suitable for optimizing gene therapy vector design.

## Abstract

Recombinant adeno-associated
viruses (rAAVs) are widely used as
vectors for gene therapy because they can target specific tissues,
exhibit low immunogenicity, and have the capacity for long-term transgene
expression. The rAAV serotype determines its tropism, therapeutic
efficacy, and suitability for specific clinical applications. Moreover,
new mutant serotypes have emerged through capsid engineering approaches.
Accurate serotype identification is therefore essential for optimizing
vector design and ensuring successful therapeutic outcomes. Conventional
methods for identifying rAAV serotypes, such as the enzyme-linked
immunosorbent assay, often involve complex procedures and rely on
specialized reagents, including antibodies. Meanwhile, liquid chromatography-tandem
mass spectrometry-based peptide mapping faces challenges in terms
of quality control. These limitations highlight the need for more
efficient and practical approaches to streamline the identification
of rAAV serotypes. This report proposes a methodology for rAAV serotype
identification using matrix-assisted laser desorption/ionization mass
spectrometry (MALDI–MS) with new scoring algorithm. The developed
method can distinguish multiple rAAV serotypes, including mutant serotypes,
by analyzing the specific peptide mass fingerprints of each serotype.
This approach eliminates the need for antibodies or extensive sample
preparation, thereby offering a reagent-free and cost-effective alternative
to conventional methods. Moreover, MALDI–MS requires small
sample quantities, making it suitable for high-throughput screening,
which can facilitate the development of tailored gene therapy vectors.
This study highlights the importance of integrating advanced analytical
technologies into gene therapy to enhance precision, reduce costs,
and ultimately improve patient outcomes.