Fig. 3: Potency, breadth, and durability of antibodies elicited by the Delta prototype mRNA-VLP vaccine in non-human primates (NHP). | npj Vaccines

Fig. 3: Potency, breadth, and durability of antibodies elicited by the Delta prototype mRNA-VLP vaccine in non-human primates (NHP).

From: Immunogenicity and efficacy of an mRNA vaccine expressing a virus-like particle spike antigen against SARS-CoV-2

Fig. 3

A Two groups of NHP (n = 6/group) were administered 10 μg of LNP-formulated mRNA vaccine (mRNA-native Delta or mRNA-VLP Delta) intramuscularly on study days 1 and 28. B Fourteen days following the second dose (study day 42), sera were collected and pseudovirus-based neutralization assays performed using a panel of SARS-CoV-2 pseudoviruses as indicated. Day 42 serum anti-SARS-CoV-2 neutralization antibody titers. The geometric mean titer (GMT) ± geometric standard deviation is shown with indicated p value comparing the mRNA-native and mRNA-VLP responses for each tested pseudovirus (pV) by the Wilcoxon-Mann-Whitney test; the dotted horizontal line indicates the assay lower limit of detection (LLD). C On study days 27 and 56, spike-specific IgG+ B cell frequencies were measured in PBMCs using flow cytometry following staining with a panel of antibodies specific for B cell markers and a fluorescent spike probe. D On study days 27 and 56, spike-specific memory CD4 + T cell frequencies and phenotypes were measured in the periphery using flow cytometry following ex vivo stimulation of PBMCs with a spike-specific overlapping peptide pool and intracellular cytokine staining for Th1 (IFNγ, IL-2, TNFα) and Th2 (IL-4, IL-13) cytokines. In the box-whisker plots, horizontal bars indicate group median, boxes are the interquartile range, and whiskers are the range. E Sera were collected at different timepoints post vaccination (as indicated) and pV-based neutralization assays were performed to evaluate anti-SARS-CoV-2 (Delta variant) neutralizing antibody titers shown as the GMT for each group with the indicated p value for each timepoint. F Approximately 196 days after the first immunization, bone marrow aspirates were processed to enumerate long-lived antibody-secreting cells among individual animals by ELISpot assay. Data are represented as the number of spot-forming cells (SFCs) per 1 × 106 bone marrow cells plated with determined p value indicated. Ab antibody, D614G ancestral D614G spike, ID50 half-maximal inhibitory dilution, native Delta full-length Delta spike protein containing the S2P pre-fusion spike stabilization mutations, ns not significant, PBMCs peripheral blood mononuclear cells.

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