Poster Presentation Asia-Pacific Vaccine and Immunotherapy Congress 2026

T cells in a drop: Rapid T-cell monitoring in infectious diseases (#120)

Shou Kit Hang 1 , Adeline Chua 2 , Nicole Tan 2 , Natalene YH Shan 2 , Shubhankar S Ambike 2 , Akshay A Binayke 2 , Yazhini Avaiarasi 2 , Yvonne LJ Mei 2 3 , Antonio Bertoletti 2 , Anthony T Tan 2 , Nina Le Bert 2
  1. T Cell Diagnostics Pte. Ltd., Singapore
  2. Duke-NUS Medical School, Singapore
  3. Universiti Malaya, Kuala Lumpur, Malaysia

Despite their crucial role in controlling viral infections and shaping disease pathogenesis, antigen-specific T-cell responses remain understudied due to the lack of simple, reliable, and scalable assays. To address this gap, we present a novel, sensitive, and rapid whole-blood assay (WBA) that enables the evaluation of virus-specific T-cell responses using small blood volumes, without the need for PBMC isolation. The assay delivers results in under 24 hours and supports the assessment of functional T cells of any specificity, making it suitable for classical research, large clinical trials, routine diagnostics, and field studies.

We validated the WBA for the precise evaluation of virus-specific T-cell responses targeting Coronaviridae, Hepadnaviridae, Paramyxoviridae, Orthomyxoviridae, Bunyaviridae, and Herpesviridae, as well as TCR-redirected T cells, in human blood. Briefly, 320 μL of whole blood is stimulated overnight with overlapping 15-mer peptides spanning the viral protein of interest. Virus-specific T cells secrete cytokines into the plasma, which are quantified using multiplex immunoassays, enabling the assessment of response magnitude and functional polarity1.

We present snapshots of diverse WBA applications, illustrating its broad utility and advantages compared with conventional T-cell assays:

  1. Tracking induction and persistence of therapeutic vaccine responses, enabling longitudinal immune monitoring across multiple time points in clinical trials2.
  2. Simultaneous detection of HBV- and HDV-specific T cells in co-infected patients, allowing immune profiling without additional sample requirements3.
  3. Detection of long-lasting DENV-specific T-cell immunity, revealing durable cellular memory in individuals with waning or undetectable antibody responses.
  4. Support of zoonotic spillover surveillance in resource-limited settings, where minimal blood volume, rapid turnaround, and limited infrastructure are critical4.
  5. Identification of distinct cytokine profiles associated with disease severity, providing functional immune signatures linked to clinical outcomes5.
  6. Assessment of the viability and functionality of TCR-reconstituted T cells, supporting immune monitoring in patients receiving T-cell–based therapies6.

Taken together, the WBA represents a versatile platform that enables virus-specific T-cell monitoring beyond specialized laboratories. Its rapid (<24 h) readout and minimal blood requirement make it broadly applicable across diverse clinical and field settings, including those with limited technical infrastructure and specialized expertise.

  1. Tan, A. T. et al. Rapid measurement of SARS-CoV-2 spike T cells in whole blood from vaccinated and naturally infected individuals. J Clin Invest 131, e152379 (2021).
  2. Ji, Y. et al. The Impact of Hepatitis B Surface Antigen Reduction via Small Interfering RNA Treatment on Natural and Vaccine (BRII-179)-Induced Hepatitis B Virus-Specific Humoral and Cellular Immune Responses. Gastroenterology 169, 136–149 (2025).
  3. Le Bert, N. et al. Rapid whole-blood immune profiling reveals heterogeneous HBV-specific T cell response patterns independent of clinical disease phases. J. Hepatol. 83, 1292–1304 (2025).
  4. Samandari, T. et al. Prevalence and functional profile of SARS-CoV-2 T cells in asymptomatic Kenyan adults. J Clin Invest 133, e170011 (2023).
  5. Le Bert, N. et al. Highly functional virus-specific cellular immune response in asymptomatic SARS-CoV-2 infection. J Exp Med 218, e20202617 (2021).
  6. Tan, A. T. et al. A rapid method to assess the in vivo multi-functionality of adoptively transferred engineered TCR T cells. Immunother. Adv. 4, ltae007 (2024).