Fig. 1.

SARS-CoV-2 directly infects the pancreatic islets of non-human primates (NHPs). a Representative multi-label IF image from the elder control NHP sample was stained for SARS-CoV-2 S1 protein (S, green), glucagon (α, red), insulin (β, cyan), somatostatin (δ, magenta), and polypeptide (P, yellow). Scale bars, 50 μm. b–d Pancreatic tissue section from one SARS-CoV-2-infected elder NHP sample was stained by the same panel of multi-label IF, showing the co-localization of S and P. Scale bars, 800 μm. c, d Representative multi-label IF image from the magnified section of (b). Inset highlights SARS-CoV-2 viral antigen co-localized with islet endocrine cells. Scale bars, 20 μm. e Pancreatic tissue section from another SARS-CoV-2-infected elder NHP sample was stained by the same panel of multi-label IF, showing the co-localization of S and markers of various islet endocrine cells. Scale bars, 800 μm. f Representative multi-label IF image from the magnified section of (e). Inset highlights co-expression of SARS-CoV-2 S protein (S, green) with glucagon (α, red), insulin (β, cyan), somatostatin (δ, magenta), and polypeptide (P, yellow). Scale bars, 100 μm. g–j Quantification of the percentage of glucagon⁺ α, insulin⁺ β, somatostatin⁺ δ, and polypeptide⁺ PP cells, as well as SARS-CoV-2 S protein⁺glucagon⁺ α, S protein⁺insulin⁺ β, and S protein⁺somatostatin⁺ δ cells, in the elder control NHPs (3 slides) and elder COVID-19 model NHPs(4 slides) (n = 10 images examined from all slides/group). Data are presented as mean ± SD. p Values were calculated by paired or unpaired two-tailed Student’s t test. *p < 0.05, **p < 0.01, and ***p < 0.001