Our automated gating approach for cytometry data was featured in a new publication in Human Vaccines & Immunotherapeutics. The study, titled “Humoral and cellular immunogenicity and safety following a booster dose of a tetravalent dengue vaccine 5+ years after completion of the primary series in Singapore: 2-year follow-up of a randomized phase II, placebo-controlled trial,” utilized our method to automate the characterization of specific polyfunctional T-cells in response to a vaccine boost.

Study Overview

The tetravalent dengue vaccine (CYD-TDV) is approved for use as a 3-dose series for preventing dengue in seropositive individuals aged 9 and above. A randomized, placebo-controlled phase II study evaluated the effects of a booster dose of CYD-TDV in individuals who completed the 3-dose schedule more than 5 years prior.

Key Findings

  • The booster dose restored neutralizing antibody titers to post-dose 3 levels.
  • Additional immunogenicity assessments were conducted up to 24 months post-booster.
  • B-cell and T-cell responses were analyzed in a subset of participants.

Participant Details

Participants aged 9–45 who had received all three doses of CYD-TDV were randomized 3:1 to receive a booster dose of CYD-TDV (n = 89) or placebo (n = 29).

Assessments

  • Neutralizing antibody levels were assessed at Months 1, 6, 12, and 24 post-booster.
  • B-cell responses were evaluated using a fluorescent immunospot assay.
  • T-cells were analyzed by flow cytometry at Days 0, 7, 12, and Months 1 and 12.

Results

  • Antibody titers increased one month post-booster, then gradually declined by Month 24.
  • In the CYD-TDV booster group, plasmablasts increased at Day 7 and declined by Day 14.
  • Memory B-cells increased at Day 28 but did not persist at Month 12.
  • The booster recalled a CD8+ T-cell response, dominated by IFN-γ secretion, which decreased 12 months post-booster.

Conclusion

The study demonstrated a short-term increase in antibody titers and memory B-cell activation following the booster, with low persistence over time.

Congratulations

Congratulations to Dr. Anke Pagnon and her team for this significant work.