Figure 6.

YF-specific memory response in adults following 17DD-YF 1/5 fractional dose primary vaccination. The YF-specific memory phenotypes of T and B-cells were evaluated upon long-term in vitro PBMC cultures carried out before [NV_(D0) = ▭, n = 15] and 30–45 days after [PV_(D30–45) = ▬, n = 15] 17DD-YF 1/5 fractional dose primary vaccination. PBMC cultures were performed in the absence (unstimulated—Control Culture) and in the presence of 17DD-YF antigen (17DD-YF stimulated—17DD-YF Culture). Immunophenotyping staining of memory phenotypes of CD4⁺ and CD8⁺ T-cell subsets (Naïve—CD45RA⁺CCCR7⁺; Central Memory—CD45RA⁻CCCR7⁺; Effector Memory—CD45RA⁻CCCR7⁻ and Terminal Effector—CD45RA⁺CCCR7⁻) and B-cells (Naive—IgD⁺CD27⁻; Double-negative—IgD⁻CD27⁻; Classical Memory—IgD⁻CD27⁺ and Non-Classical Memory—IgD⁺CD27⁺) was carried out by mass cytometry by time-of-flight (CyTOF) as described in “Methods” section. Results are shown as mean values ± standard error of 17DD-YF Culture/Control Culture Index. Comparative analysis of YF-specific memory phenotypes of CD4⁺ (A), CD8⁺ T-cells (B) and B-cells (C) between NV_(D0) and PV_(D30–45) was carried out by Student t test. Significant differences were considered as p ≤ 0.05 and highlighted by *. Color background underscores cell phenotypes with increased (pink) or decreased (green) values in PV_(D30–45) as compared to NV_(D0).