T-cell biomarkers for diagnosis of tuberculosis: candidate evaluation by a simple whole blood assay for clinical translation

To advance research and development of improved pertussis vaccines, new immunoassays are needed to qualify the outcome of Bordetella pertussis (Bp) specific CD4+ T-cell differentiation. Here, we applied a recently developed whole blood assay to evaluate Bp specific CD4+ T-cell responses. The assay is based on intracellular cytokine detection after overnight in vitro Bp antigen stimulation of diluted whole blood. We show for the first time that CD4+ T-cell memory of Th1, Th2, and Th17 lineages can be identified simultaneously in whole blood. Participants ranging from 7 to 70 years of age with different priming backgrounds of whole-cell pertussis (wP) and acellular pertussis (aP) vaccination were analyzed around an acellular booster vaccination. The assay allowed detection of low frequent antigen-specific CD4+ T-cells and revealed significantly elevated numbers of activated and cytokine-producing CD4+ T-cells, with a significant tendency to segregate recall responses based on primary vaccination background. A stronger Th2 response hallmarked an aP primed cohort compared to a wP primed cohort. In conclusion, analysis of Bp specific CD4+ T-cell responses in whole blood showed separation based on vaccination background and provides a promising tool to assess the quantity and quality of CD4+ T-cell responses induced by vaccine candidates.

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Rapid, simplified whole blood-based multiparameter assay to quantify and phenotype SARS-CoV-2 specific T cells

10.1101/2020.10.30.20223099 ◽

2020 ◽

Author(s):

Catherine Riou ◽

Georgia Schäfer ◽

Elsa du Bruyn ◽

Rene T. Goliath ◽

Cari Stek ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Whole Blood ◽

T Cell Responses ◽

Cd4 T Cell ◽

Proof Of Concept ◽

Whole Blood Assay ◽

Cell Responses ◽

Vaccine Trials ◽

Blood Assay

ABSTRACTRapid tests to evaluate SARS-CoV-2-specific T cell responses are urgently needed to decipher protective immunity and aid monitoring vaccine-induced immunity. Using a rapid whole blood assay requiring minimal amount of blood, we measured qualitatively and quantitatively SARS-CoV-2-specific CD4 T cell responses in 31 healthcare workers, using flow cytometry. 100% of COVID-19 convalescent participants displayed a detectable SARS-CoV-2-specific CD4 T cell response. SARS-CoV-2-responding cells were also detected in 40.9% of participants with no COVID-19-associated symptoms or who tested PCR negative. Phenotypic assessment indicated that, in COVID-19 convalescent participants, SARS-CoV-2 CD4 responses displayed an early differentiated memory phenotype with limited capacity to produce IFNγ. Conversely, in participants with no reported symptoms, SARS-CoV-2 CD4 responses were enriched in late differentiated cells, co-expressing IFNγ and TNFα and also Granzyme B. This proof of concept study presents a scalable alternative to PBMC-based assays to enumerate and phenotype SARS-CoV-2-responding T cells, thus representing a practical tool to monitor adaptive immunity in vaccine trials.SummaryIn this proof of concept study, we show that SARS-CoV-2 T cell responses are easily detectable using a rapid whole blood assay requiring minimal blood volume. Such assay could represent a suitable tool to monitor adaptive immunity in vaccine trials.

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