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. 2021 Oct 13;95(21):e01264-21. doi: 10.1128/JVI.01264-21

FIG 4.

FIG 4

Olfactory vaccination with spread-deficient ΔM33 MCMV protects against superinfection with Δm157 pARK MCMV. Adult BALB/c mice were given olfactory vaccinations with either WT MCMV or ΔM33 MCMV (n = 10 per virus group; 5 × 105 PFU in 4 μl). Controls were unvaccinated mice (n = 5). After 1 month, all mice were challenged with 5 × 105 PFU Δm157 pARK MCMV via the same route. (A) Serum IgM and IgG levels determined pre- and postchallenge by ELISA. Each point represents the means ± the SEM from 10 individual serum samples per group. Differences in antibody titers were compared between vaccinated and unvaccinated groups (**, P < 0.01; ***, P < 0.001). (B) Infectious MCMV titers in salivary glands of vaccinated and unvaccinated mice from panel A were determined at day 14 postchallenge with Δm157 pARK MCMV. One of ten mice in the WT MCMV-vaccinated group showed a reduced level of infection. No virus was detected ΔM33 MCMV-vaccinated counterparts. Symbols show the values for individual mice; bars depict means. The dashed line corresponds to the assay sensitivity limit. The data are representative of three separate experiments. (C) DNA was extracted from randomly selected salivary gland homogenates from panel B and assessed for MCMV gDNA by qPCR. Unvaccinated, Δm157pARK-challenged mice exhibited high levels of gDNA; levels for ΔM33MCMV salivary glands were below the limit of detection. (D) Adult BALB/c mice were given olfactory vaccinations with either ΔM33 MCMV or ΔgL (n = 10 per virus group; 5 × 105 PFU/mouse). Controls were unvaccinated mice. After 1 month, all mice were challenged with 5 × 105 PFU Δm157pARK MCMV. IgM and IgG antibodies were quantified by ELISA; each point represents the means ± the SEM of 10 mice. Differences in antibody titers were compared between vaccinated and unvaccinated groups (**, P < 0.01; ***, P < 0.001). ΔgL-vaccinated mice did not exhibit antibody titers significantly different from unvaccinated controls. (E) MCMV titers in the salivary glands of vaccinated and unvaccinated mice in panel D were determined 14 days postchallenge and showed modest reduction by ΔgL vaccination; no infectious virus was detected in ΔM33 MCMV-vaccinated mice.