We are releasing two PepPools today. Both peptide pools are derived from the vaccinia virus, which is used as the vaccine against smallpox. PepPool: Vaccinia (CD8), human includes 102 MHC-I binding peptides covering 59 vaccinia proteins. This peptide pool can be used to induce antigen-specific CD8 T cell responses. PepPool: Vaccinia (CD4), human contains 56 MHC-II binding peptides covering 34 vaccinia proteins for the stimulation of CD4 T cells.
We have validated both PepPools using IFN‑γ ELISpot and FluoroSpot with PBMCs from individuals who received the smallpox vaccine during childhood. You can use the pools individually to differentiate between a CD4 and a CD8 T cell response. Alternatively, you can mix the peptide pools and add them together to induce an antigen-specific response.
The majority of peptides included in both pools have 100% sequence identity to the mpox virus. Thus, these pools should also stimulate a T cell response in individuals that have undergone a mpox infection.
Update (2022-12-22)
We initially validated our two Vaccinia PepPools with samples from individuals vaccinated in childhood using a Human IFN‑γ ELISpot.
Today, we can report that a customer has successfully validated our Vaccinia PepPools on clinical samples. Immune responses have been detected in both an individual infected with mpox and in an individual that was vaccinated in childhood and obtained a booster dose of a novel mpox vaccine in 2022.
PBMCs from an individual infected with mpox
unstimulated
0 spots
stimulated, PepPool: Vaccinia (CD8)
70 spots
unstimulated
2 spots
stimulated, PepPool: Vaccinia (CD4)
40 spots
PBMCs from an individual vaccinated in childhood and obtained a booster dose of JYNNEOS in 2022 (attenuated live virus vaccine based on MVA - modified vaccinia ankara, replication-deficient smallpox vaccine - licensed by the FDA for prevention of smallpox and mpox)
unstimulated
5 spots
stimulated, PepPool: Vaccinia (CD8)
37 spots
stimulated, PepPool: Vaccinia (CD4)
21 spots