Accurate HLA Typing Services - 99.99% Accuracy with Multi-Platform Solutions

Table of HLA Type Details (Mayor NP et al., PLoS One. 2015)

Distribution of HLA Allelic Presentation (Nguyen A et al., Journal of virology, 2020)

Distribution of Allelic Presentation for All HLA Alleles and Individually for HLA-A, HLA-B, and HLA-C (Nguyen A et al., Journal of virology, 2020)

References

1. Mayor NP, Robinson J, McWhinnie AJM, et al. HLA Typing for the Next Generation. PLoS One. 2015;10(5):e0127153. https://doi.org/10.1371/journal.pone.0127153
2. Nguyen A, David JK, Maden SK, et al. Human leukocyte antigen susceptibility map for severe acute respiratory syndrome coronavirus 2. Journal of virology. 2020 Jun 16;94(13):10-128. https://doi.org/10.1128/jvi.00510-20

1. What information can be obtained through HLA gene sequencing and information analysis?

Through NGS, HLA typing enables precise identification of specific allele information at each HLA locus, distinguishing between classical and non-classical HLA genes. It also determines specific combinations of HLA allele groups inherited together on a single chromosome. Additionally, NGS-based methods detect previously unreported alleles and ascertain whether each HLA locus is homozygous or heterozygous.

NGS-based HLA typing methods offer advantages of high accuracy, resolution, throughput, and cost-effectiveness. However, the accuracy of NGS-based HLA typing heavily depends on bioinformatics analysis methods, showing significant variability among different approaches.

2. What are the main methods of genotyping?

Serological typing: Focused on the specificity of HLA antigens, this method mainly employs HLA microcytotoxicity tests to analyze HLA types. Serological methods are vital for determining HLA typing and serve as the internationally recognized standard technique.

DNA typing: Concentrating on the analysis of genes themselves, this approach encompasses two main methods: those based on nucleic acid sequence identification and those based on sequence molecular configuration. The nucleic acid sequence identification methods primarily include PCR-RFLP, PCR-SSO, PCR-SSP, PCR-SBT, and the recently emerging next-generation sequencing methods.

3. Is NGS-based HLA typing suitable for clinical applications?

Indeed, NGS-based HLA typing is increasingly being integrated into clinical practice, particularly for organ transplantation, disease association studies, and pharmacogenomics. Its capability to provide high-resolution and precise allele determination enhances compatibility assessments and supports the development of individualized therapeutic strategies.

4. What level of precision is typically required in genotyping?

The specificity of the genotyping should ideally meet the criteria set by the recording of HLA types in the IMGT/HLA database. Differences in the four-digit typing correspond to variations in the encoded proteins, which generally fulfill the demands of scientific research. However, for studies necessitating higher accuracy or specific cases in transplant matching, a six-digit typing may be necessary to acquire more detailed allelic information.

Customer Publication Highlight

The HLA class I immunopeptidomes of AAV capsid proteins

Journal: Frontiers in Immunology
Impact Factor: 8.786 (2022)
Published: 16 August 2023

Background

Adeno-associated viruses (AAVs) are widely used in gene delivery but face challenges due to immune responses against their capsid proteins. CD8+ T cells recognize HLA class I-presented peptides, but the natural repertoire of AAV capsid-derived peptides remains poorly characterized. This study aimed to identify the HLA class I immunopeptidomes of AAV2, AAV6, and AAV9 using mRNA-transfected monocyte-derived dendritic cells (MDDCs) and mass spectrometry. The goal was to map naturally processed peptides, assess cross-reactivity among serotypes, and refine immunogenicity risk assessment for gene delivery systems.

Materials & Methods

Results

1. HLA Class I Immunopeptidome Profiling
   • Identified 65 unique AAV capsid peptides (26 from AAV2, 28 from AAV6, 41 from AAV9).
   • Peptide Length: 59% 9-mer, 23% 10-13-mer (non-canonical lengths).
   • Allele Distribution: 43 peptides bound HLA-B, 15 HLA-A, 7 HLA-C.

Table 1 Donor HLA alleles and frequencies in the US population.

The HLA class I immunopeptidomes of AAV serotypes.

2. Comparison with Previous Studies
   • Overlap: 6 peptides matched known immunogenic epitopes (e.g., VPQYGYLTL, IPQYGYLTL).
   • Novel Peptides: 59 peptides (91% of total) were newly identified.

Table 2 Naturally processed HLA class I peptides and their match with previous identified epitopes.

3. Conservation and Cross-Reactivity
   • 11 Highly Conserved Peptides: Identified across AAV2, AAV6, and AAV9, including regions with single-residue variations.
   • Cross-Reactivity Potential: Conserved peptides (e.g., DTSFGGNLGR) may activate CD8+ T cells across serotypes.

Eleven HLA class I peptides are highly conserved among AAV2, AAV6 and AAV9.

4. HLA Class I/II Overlap
   • 60% of HLA class I peptides overlapped with HLA class II clusters, suggesting dual presentation potential.

More than 60% of the AAV HLA class I peptides are contained within HLA class II clusters.

Conclusion

This study provides the first comprehensive analysis of HLA class I immunopeptidomes for AAV capsids, identifying 65 peptides (59 novel) and highlighting conserved regions with cross-reactivity potential. These findings enhance understanding of AAV-specific CD8+ T cell responses and inform strategies to mitigate immunogenicity in gene delivery systems. Future work should validate the immunogenicity of newly identified peptides and assess cross-presentation mechanisms in experimental models.

Reference

1. Brito-Sierra, Carlos A., et al. "The HLA class I immunopeptidomes of AAV capsid proteins." Frontiers in Immunology 14 (2023): 1212136. https://doi.org/10.3389/fimmu.2023.1212136