Using lymph node slices to study vaccine adjuvants ex vivo

• Published in: The Journal of immunology (1950) 2020-05, Vol.204 (1_Supplement), p.166-166.23
• Main Authors: Ball, Alexander, Catterton, Megan A, Pompano, Rebecca R
• Format: Article
• Language: English
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.204.Supp.166.23

Despite the success of vaccines in preventing infectious diseases, there is a growing need for the development of new vaccine adjuvants. We recently demonstrated that live lymph node (LN) slices serve as a unique platform to study adaptive immunity ex vivo. These slices enable visualization of changes in the spatial organization and activation state of the tissue during an immune response. Here we hypothesized that different adjuvants induce unique cytokine and spatial profiles within tissue, and we examined the influence of three adjuvants (alum, CFA, & poly I:C) to test this. We transferred ovalbumin (OVA)-specific CD4+ T cells (OTII) into C57BL/6 mice before vaccinating the mice with OVA protein and adjuvant. LNs were collected on days 1, 4, and 7, sliced on a vibratome, and cultured overnight with either the intact OVA protein or PBS. The supernatant was analyzed for cytokine secretion by ELISA (IFNγ, TNFα, and IL-4) from cultured slices. Slices were immunostained for activation markers, CD69 and CD22, and analyzed with fluorescent imaging. Cytokine secretion was greatest in slices from vaccinated mice that had been co-cultured with the OVA protein in comparison to slices that were either cultured or immunized with PBS. The different adjuvants induced unique cytokine profiles in slices both in terms of timing and magnitude as TNFα, IFNγ, and IL-4 peaked on different days from one another within the same vaccination scheme as well as between adjuvants. The spatiotemporal distribution of T cell and B cell activation markers also differed between adjuvants. This study demonstrates that LN slices can analyze the unique influences of different adjuvants and highlights slices as a potential screen for novel vaccine adjuvants.