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Ivleva VB, Gowetski DB, Lei QP. Streamlining Peptide Mapping LC-MS Approach for Studying Fusion Peptide-Conjugated Vaccine Immunogens. J Am Soc Mass Spectrom 2021; 32:2777-2790. [PMID: 34751576 PMCID: PMC10157672 DOI: 10.1021/jasms.1c00211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A newly introduced HIV-1 vaccination utilizes a fusion peptide (FP)-based immunogen-carrier conjugate system, where the FP is coupled to a protein carrier via a bifunctional linker. Such heterogeneous materials present a challenge for the routine product quality assessment. Peptide mapping LC-MS analysis has become an indispensable tool for assessing the site-specific conjugation ratio, estimating site occupancy, monitoring conjugation profiles, and analyzing post-translational modifications (PTMs) and disulfide bonds as well as high-order protein structures. To streamline the peptide mapping approach to match the needs of a fast-paced conjugate vaccine product characterization, a selection of signature fragment ions generated by MSE fragmentation was successfully applied to assess the product quality at the different stages of a conjugates' manufacturing process with an emphasis on monitoring the amount of a reactive linker. This technique was employed in different conjugation studies of the protein carriers, linkers, and FP compositions as well as the cross-linked species formed during stress-degradation studies. Multiple derivatives of the intermediate and final conjugated products formed during a multistaged synthesis were monitored by means of the sensitive extracted-ion chromatogram (XIC) profiling and were included in the estimation of the site-specific conjugation loads. Differentiation of the conjugates with various FP compositions was demonstrated. The conjugation site occupancy was evaluated with respect to the solvent exposure of Lys residues. The findings of these LC-MS studies greatly aided in choosing the best conjugation strategy to ensure that the final recombinant tetanus toxoid heavy chain (rTTHc) product is chemically inert and represents a safe vaccine candidate for clinical evaluation.
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Affiliation(s)
- Vera B Ivleva
- Vaccine Production Program, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
| | - Daniel B Gowetski
- Vaccine Production Program, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
| | - Q Paula Lei
- Vaccine Production Program, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, Maryland 20878, United States
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Yang GJ, Yang Y, Shaddeau A, Cai CX, Li Y, Gulla K, Zhang Y, Ou L, Cooper JW, Lei QP. A unique algorithm for the determination of peptide-carrier protein conjugation ratio by amino acid analysis using intrinsic internal standard. Vaccine 2020; 38:4507-4511. [PMID: 32448620 DOI: 10.1016/j.vaccine.2020.04.080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/29/2020] [Accepted: 04/30/2020] [Indexed: 11/26/2022]
Abstract
An N-terminal peptide of the HIV-1 fusion peptide (FP) with eight amino acid residues (FP8) was conjugated to a recombinant Tetanus Toxoid Heavy Chain Fragment C (rTTHc) as a carrier protein to help boosting immunogenicity against HIV-1. In this rapid communication, a unique algorithm to determine FP-rTTHc conjugation ratio was developed based off the amino acid analysis. Five well recovered amino acids (present in both FP and rTTHc) were used to calculate the conjugation ratio, while proline (present only in rTTHc) was identified and utilized as the intrinsic internal standard for normalization. With this calculation, the assay variability was minimized (<20%), especially for conjugates with moderate to low conjugation ratios as being compared to previously reported methods. The approach offers a reliable tool to determine the efficiency of the conjugation reactions for in-process monitoring and for final conjugate product characterization.
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Affiliation(s)
- Gengcheng J Yang
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, MD, United States
| | - Yanhong Yang
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, MD, United States
| | - Andrew Shaddeau
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, MD, United States
| | - Cindy X Cai
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, MD, United States
| | - Yile Li
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, MD, United States
| | - Krishana Gulla
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, MD, United States
| | - Yaqiu Zhang
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, MD, United States
| | - Li Ou
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, MD, United States
| | - Jonathan W Cooper
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, MD, United States
| | - Q Paula Lei
- Vaccine Production Program Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Gaithersburg, MD, United States.
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