Article
Extended Data Fig. 11 | Immune response to BCG 6 months after vaccination.
Analysis of tissue T cell responses, lung cell counts, immunohistochemistry,
splenic volume and PET–CT scans was performed 6 months after BCG
vaccination. a–c, A separate cohort (cohort 3, n = 3 macaques) was vaccinated
with BCG in parallel to the challenge study with the purpose of assessing
immune responses in various tissues 6 months after BCG (the time point at
which macaques would be challenged). a, b, Frequency of memory CD4 (a) and
CD8 (b) T cells producing any combination of IFNγ, IL-2, TNF, or IL-17 in
response to Mtb WCL stimulation in the PBMC, spleen, bone marrow,
peripheral LN, lung LN, lung tissue and BAL. Six months after IV BCG,
immunized NHPs maintained increased frequencies of antigen-responsive
T cells in spleen, BAL and lung lobes. Individual LN and lung lobe responses
were averaged per macaque. Data points are individual macaques with symbols
matched across tissues within a vaccine group; horizontal bar indicates the
mean response. c, Number of cells recovered per gram of lung tissue for each
NHP; the increased numbers of total cells observed at 1 month post-BCG
(Fig. 3d) were not detected at 6 months post-BCG. Data are shown as the
median of 3 macaques per group (solid symbols, counts from six lung lobes per
animal are averaged) or as counts for individual lung lobes for each animal
(open symbols; lobes from the same animal have matched symbols). Kruskal–
Wallis test was used, and P values represent Dunn’s multiple comparison test
comparing each vaccine group to the IDlow group. d, Quantification of CD3+,
CD20+, CD11c+ cells from two lung sections (matched symbols) from 1–2
macaques per group using Cell Profiler. e, Representative 1-mm^2 lung sections
from 1–2 macaques per vaccine group were stained with H&E or with antibodies
against CD3+ T cells (red), CD20+ B cells (green), and CD11c+ macrophages or
dendritic cells (blue). Neither the increase in numbers of T cells and CD11c+ cells
nor the histopathological changes in lung sections from IV-BCG-immunized
macaques observed at 1 month (Fig. 3e, f) were detected 6 months after BCG
vaccination. f, Spleen volume was calculated from CT scans of 44 NHPs
(cohorts 1–3) just before Mtb challenge (6 months after BCG vaccination) and
was not significantly different among vaccine routes (Kruskal–Wallis test,
P = 0.1643). Dots represent individual animals. g, Axial (top) and coronal
(bottom) PET–CT scans of two representative macaques (n = 8–10) from each
vaccine group 6 months after BCG, before Mtb infection. Animal ID numbers
are shown below each set of scans. No detectable lung inf lammation (FDG
uptake) was observed in macaques from any vaccine group.