Background information
SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) was first detected in December 2019 in Wuhan, China. Since that time the virus kept mutating, leading to new virus variants. The B.1.1.529 lineage, also known as Omicron variant, is a SARS-CoV-2 variant that was first discovered in South Africa and Botswana in November 2021. The variant has been further classified into sublineages, such as BA.1, BA.2, and BA.5. The B.1.1.529/BA.5 variant has mutated further, resulting in additional sublineages, including BQ.1 and BQ.1.1. BQ.1.1 carries spike protein mutations at several key antigenic sites that have been associated with immune evasion. In total there are 37 mutations in the surface or spike glycoprotein (“S”) of the BQ.1.1 lineage compared to the Wuhan variant (reference genome GenBank MN908947.3): T19I, L24 deletion, P25 deletion, P26 deletion, A27S, H69 deletion, V70 deletion, G142D, V213G, G339D, R346T, S371F, S373P, S375F, T376A, D405N, R408S, K417N, N440K, K444T, L452R, N460K, S477N, T478K, E484A, F486V, Q498R, N501Y, Y505H, D614G, H655Y, N679K, P681H, N764K, D796Y, Q954H, N969K.
The PepTivator SARS-CoV-2 Prot_S B.1.1.529/BQ.1.1 WT Reference Pool covers positions T19, L24, P25, P26, A27, H69, V70, G142, V213, G339, R346, S371, S373, S375, T376, D405, R408, K417, N440, K444, L452, N460, S477, T478, E484, F486, Q498, N501, Y505, D614, H655, N679, P681, N764, D796, Q954, and N969 of the Wuhan variant (reference genome GenBank MN908947.3). It consists of peptides of 15 aa length and serves as a control for the PepTivator SARS-CoV-2 Prot_S BQ.1.1 Mutation Pool. Comparison of the T cell immune response upon stimulation with mutation and reference pool can be used to analyze mutation-specific T cell responses.
Applications
PepTivator® SARS-CoV-2 Prot_S BQ.1.1 – research grade has been specifically developed for in vitro stimulation of SARS-CoV-2– specific T cells. Peptides of 15 amino acids in length and 11 amino acids overlap represent an optimized solution for stimulating both CD4+ and CD8+ T cells in various applications, including:
- Detection and analysis of SARS-CoV-2–specific CD4+ and CD8+ effector/memory T cells in PBMCs by MACS® Cytokine Secretion Assays, intracellular cytokine staining, or other technologies.
- Isolation of viable SARS-CoV-2–specific CD4+ T cells with the CD154 MicroBead Kit, or of viable CD4+ and CD8+ T cells using MACS Cytokine Secretion Assay – Cell Enrichment and Detection Kits. Subsequently, cells can be expanded for generation of T cell lines.
- Generation of SARS-CoV-2–specific CD4+ and CD8+ effector/ memory T cells from naive T cell populations.
- Pulsing of antigen-presenting cells, e.g. for research on dendritic cell vaccination.
More information regarding the work with antigen-specific T cells can be found in the T cell application section.
Overview
Stimulate T cells reactive to the spike protein of SARS-CoV-2 BQ.1.1, an Omicron sublineage emerged from Omicron subvariant B.1.1.529 /BA.5, using PepTivator Peptide Pools. PepTivators are pools of lyophilized peptides, consisting mainly of 15-mer sequences with 11 amino acids overlap. The PepTivator Mutation Pools selectively cover the mutated regions in the surface or spike glycoprotein (“S”) of the respective variant, whereas WT Reference Pools cover the homologous domains of the Wuhan sequence.
In vitro stimulation of antigen-specific T cells with PepTivator Peptide Pools causes the secretion of effector cytokines and the up-regulation of activation markers, which then allow the detection and isolation of antigen-specific T cells.
