Skip to main content

LC-MS/MS characterization of #SOBERANA®02, a #RBD - #tetanus toxoid conjugate #vaccine against #SARS-CoV-2

Image
By G.M.

Abstract

SOBERANA-02 is a safe and effective conjugate vaccine against SARS-CoV-2, produced using the maleimide-thiol chemistry. In this vaccine, the Cys538 in the recombinant receptor binding domain (RBD) of SARS-CoV-2 is linked, through a thiosuccinimide linker, to lysine residues of tetanus toxoid (TT) preparation. LC-MS/MS analysis revealed that TT is a complex mixture of proteins, similar to other TTs where the detoxified tetanus neurotoxin (d-TeNT) has been shown to be the most abundant protein (30-56%), regardless the quantification method used. The fifteen most abundant proteins account for approximately 78% of the total proteins. LC-MS/MS analysis of the activation process showed that 102 out of 107 lysine residues in the d-TeNT incorporated a maleimide group. In contrast, when tryptic peptides isolated by Ni2+-NTA affinity chromatography, were analyzed by LC-MS/MS, only 22 Lys residues in the d-TeNT were cross-linked to the RBD C-terminal tryptic peptide (538CVNF541-HHHHHH), probably due to steric hindrance. Twelve and eighteen conjugation sites were assigned based on the identification of linear peptides carrying a conjugated lysine residues (K(+1454.58 Da) or K(+1472.59 Da)) and cross-linked peptides with stabilized linker forms, respectively. Eight conjugation sites were coincidently assigned by both strategies. The assignment of the conjugation sites was manually validated by observed regularities (z equal or higher to 3+, XIC, immonium ions, specific linker fragment ions) not considered by the identification software (PEAKS, Kojak and pLink2). The RBD was also conjugated, but to a lesser extent, to ten other low abundance carrier proteins. To our knowledge, this work is the first report of conjugation site assignment in a TT-based conjugate vaccine.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.12.27.630511v1?rss=1

_____

Labels:

Comments

Post a Comment

Popular posts from this blog

#Neuroinvasive #Oropouche virus in a patient with #HIV from extra-Amazonian #Brazil

By G.M.
{Excerpt} A novel reassortant Oropouche virus (OROV) lineage (with medium [M], large [L], and small [S] RNA segments : M1L2S2) has driven Brazil's largest and most geographically widespread OROV epidemic , expanding beyond the endemic Amazon basin to establish local transmission across multiple Brazilian states and other previously unaffected Latin American countries . The rapid spread of this lineage underscores its evolutionary potential and reinforces its significance as a public health threat .1 Similar to chikungunya and Zika viruses, expanding arboviruses can exhibit unexpected clinical and epidemiological shifts , including vertical transmissions , neuroinvasive effects, and potentially fatal outcomes.2–4 Although OROV typically causes self-limited febrile illness, accumulating clinical and experimental evidence suggests neurotropic potential .5 This Correspondence describes the first confirmed case of neuroinvasive OROV infection caused by the emergent M1L2S2 lineage in ext...
Post a Comment
Read more »

No evidence of immune #exhaustion after repeated #SARS-CoV-2 #vaccination in vulnerable and healthy populations

By G.M.
Abstract Frequent SARS-CoV-2 vaccination in vulnerable populations has raised concerns that this may contribute to T cell exhaustion , which could negatively affect the quality of immune protection. Herein, we examined the impact of repeated SARS-CoV-2 vaccination on T cell phenotypic and functional exhaustion in frail older adults in long-term care (n = 23), individuals on immunosuppressive drugs (n = 10), and healthy adults (n = 43), in Canada . Spike-specific CD4+ and CD8+ T cell levels did not decline in any cohort following repeated SARS-CoV-2 vaccination, nor did the expression of exhaustion markers on spike-specific or total T cells increase. T cell production of multiple cytokines (i.e. polyfunctionality) in response to the spike protein of SARS-CoV-2 did not decline in any cohort following repeated vaccination. None of the cohorts displayed elevated levels of terminally differentiated T cells following multiple SARS-CoV-2 vaccinations. Thus, repeated SARS-CoV-2 vaccination was...
Post a Comment
Read more »

Chimeric #hemagglutinin and #M2 #mRNA #vaccine for broad #influenza subtype protection

By G.M.
Abstract Since multiple and unpredicted influenza viruses cause seasonal epidemics and even high-risk pandemics , developing a universal influenza vaccine is essential to provide broad protection against various influenza subtypes. Combined with the mRNA lipid nanoparticle-encapsulated (mRNA-LNP) vaccine platform and chimeric immunogen strategy , we developed a novel cocktail mRNA vaccine encoding chimeric HAs (cH5/1-BV, cH7/3) and intact M2 (termed Fluaxe), which confers broad protection against major circulating IAVs and IBVs , as well as highly pathogenic avian influenza . Two-dose intramuscular immunization of Fluaxe in mice elicited cross-reactive neutralizing antibodies , T cell responses, and long-lived immunity, resulting in robust protection against multiple lethal influenza virus infections and severe acute lung injuries . In particular, intramuscular administration stimulated systemic immunity together with a prominent lung tropism of memory cells . Moreover, Fluaxe immuniza...
Post a Comment
Read more »