A single birth dose of Hepatitis B vaccine induces polyfunctional CD4⁺ T helper cells

Area of Science:

• Immunology
• Vaccinology
• Pediatrics

Background:

• Hepatitis B vaccine (HepB) administered at birth prevents vertical transmission but requires multiple doses for long-term immunity.
• A birth dose may induce polyfunctional CD4+ T-cells, contributing to initial protection.
• Understanding the early T-cell response is crucial for optimizing infant vaccination strategies.

Purpose of the Study:

• To determine if a single birth dose of HepB induces detectable antigen-specific CD4+ T-cells.
• To assess T-cell responses after the complete 3-dose HepB vaccine schedule.
• To correlate T-cell responses with antibody titers.

Main Methods:

• Analysis of peripheral blood mononuclear cells from 344 infants stimulated with HBsAg.
• Detection of polyfunctional CD154+IL-2+TNFα+ CD4+ T-cells.
• Measurement of serum antibody titers at day 30 and day 128.

Main Results:

• A proportion of infants showed increased polyfunctional CD4+ T-cells after a single birth dose of HepB.
• T-cell frequencies increased after the 3-dose schedule, with marginal increases in responder proportions.
• Polyfunctional T-cells positively correlated with antibody titers post-birth dose and post-primary series.

Conclusions:

• A single birth dose of HepB initiates immune priming, stimulating both B-cell (antibody) and T-cell responses.
• The HepB birth dose contributes to early immune protection in newborns.
• Early T-cell induction suggests a role in the protective efficacy of the HepB birth dose.