Cytokine Responses Induced by Respiratory Measles Dry Powder Vaccine (MVDP)
Recent research into respiratory delivery of a measles dry powder vaccine (MVDP) in macaques has revealed robust and multifunctional T cell responses, particularly involving key cytokines such as interferon-gamma (IFN-γ), tumor necrosis factor (TNF), and interleukin-2 (IL-2).
Early T Cell Activation After MVDP Immunization
Two weeks post-immunization, monkeys that received MVDP through a Puff-mask developed high frequencies of CD4+ T cells that produced IFN-γ and TNF, and more importantly, polyfunctional CD4+ T cells that co-produced IFN-γ, TNF, and IL-2. This multifunctionality is a strong indicator of high-quality T cell responses, associated with effective viral control and long-term immune protection.
Memory T Cell Responses
At 8 weeks, MeV-specific memory CD4+ and CD8+ T cells were still detectable, and Puff-mask–immunized monkeys exhibited a higher frequency of polyfunctional CD4+ memory T cells producing IFN-γ, TNF, and IL-2 compared to those vaccinated with the standard LAMV via subcutaneous injection. Notably, there were no major differences in CD8+ T cell quality between delivery methods.
Protective Immunity and Cytokine Markers
After challenge with wild-type measles virus 14–16 months later, monkeys vaccinated with MVDP via Puff-mask, Sol-mask, or Sol-nasal devices showed complete protection — no rash, no viremia, and no respiratory virus replication. These animals also showed minimal IFN-γ responses post-challenge, suggesting solid pre-existing immunity. In contrast, monkeys that became infected displayed more pronounced IFN-γ responses, likely due to secondary activation.
Key Takeaways on Cytokine IL-2
- IL-2 was a marker of multifunctional CD4+ T cells in MVDP-immunized monkeys.
- Its co-expression with IFN-γ and TNF indicates a robust helper T cell response, crucial for long-term immune memory.