Prime and Boost Vaccination Elicit a Distinct Innate Myeloid Cell Immune Response

Abstract

Understanding the innate immune response to vaccination is critical in vaccine design. Here, we studied blood innate myeloid cells after first and second immunization of cynomolgus macaques with the modified vaccinia virus Ankara. The inflammation at the injection site was moderate and resolved faster after the boost. The blood concentration of inflammation markers increased after both injections but was lower after the boost. The numbers of neutrophils, monocytes, and dendritic cells were transiently affected by vaccination, but without any major difference between prime and boost. However, phenotyping deeper those cells with mass cytometry unveiled their high phenotypic diversity with subsets responding differently after each injection, some enriched only after the primary injection and others only after the boost. Actually, the composition in subphenotype already differed just before the boost as compared to just before the prime. Multivariate analysis identified the key features that contributed to these differences. Cell subpopulations best characterizing the post-boost response were more activated, with a stronger expression of markers involved in phagocytosis, antigen presentation, costimulation, chemotaxis, and inflammation. This study revisits innate immunity by demonstrating that, like adaptive immunity, innate myeloid responses differ after one or two immunizations.

NK cell immune responses differ after prime and boost vaccination

“…Other studies in mice reported that NK cells are recruited to tissues in response to MVA‐induced CCL2 (MCP‐1) expression by macrophages . We previously reported a difference in the level of CCL2 in the blood of macaques after an MVA boost relative to prime . These and other studies show that MVA modulates NK cell activity and trafficking.…”

“…Fixed leukocytes were prepared for mass cytometry using a previously described cell fixation protocol, which allows the recovery of all leukocytes, including granulocytes, from lithium‐heparin whole blood. Briefly, 1 mL of blood was incubated with a fixation buffer containing formaldehyde and glycerol for 10 min at 4°C.…”

“…Fixed leukocyte staining and acquisition protocols were identical to those previously described . The 31‐marker antibody panel used in the present study is described in Table .…”

“…Replicates were concatenated using the tool from Cytobank (Mountain View, USA). Leukocytes were gated based on event length, iridium content, and exclusion of nonspecifically stained CD66 + CD3 + eosinophils …”

“…We previously uncovered the phenotypic complexity and diversity of innate myeloid cells in the blood and the impact of vaccinations on the dynamics of their subset composition by mass cytometry in cynomolgus macaques immunized with a recombinant MVA HIV‐B. We used the very same animals and a similar analytical workflow, but a 31‐marker mass cytometry antibody panel dedicated to the analysis of NK cells, to determine the phenotype of blood NK cell subpopulations, as well as their diversity and evolution throughout the vaccination process.…”