SARS-CoV-2 variants induce distinct disease and impact in the bone marrow and thymus of mice

Rute Gonçalves; Joana Couto; Pedro Ferreirinha; José Maria Costa; Diogo Silvério; Marta L Silva; Ana Isabel Fernandes; Pedro Madureira; Nuno L Alves; Sofia Lamas; Margarida Saraiva

doi:10.1016/j.isci.2023.105972

SARS-CoV-2 variants induce distinct disease and impact in the bone marrow and thymus of mice

iScience. 2023 Feb 17;26(2):105972. doi: 10.1016/j.isci.2023.105972. Epub 2023 Jan 13.

Authors

Rute Gonçalves¹, Joana Couto¹, Pedro Ferreirinha^{1

2}, José Maria Costa^{1

3}, Diogo Silvério^{1

4}, Marta L Silva^{1

4}, Ana Isabel Fernandes^{1

4}, Pedro Madureira^{1

5}, Nuno L Alves^{1

2}, Sofia Lamas^{1

2}, Margarida Saraiva^{1

2}

Affiliations

¹ i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.
² IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
³ FEUP-Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal.
⁴ ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal.
⁵ Immunethep, Biocant Park, 3060-197 Cantanhede, Portugal.

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has evolved to variants associated with milder disease. We employed the k18-hACE2 mouse model to study how differences in the course of infection by SARS-CoV-2 variants alpha, delta, and omicron relate to tissue pathology and the immune response triggered. We documented a variant-specific pattern of infection severity, inducing discrete lung and blood immune responses and differentially impacting primary lymphoid organs. Infections with variants alpha and delta promoted bone marrow (BM) emergency myelopoiesis, with blood and lung neutrophilia. The defects in the BM hematopoietic compartment extended to the thymus, with the infection by the alpha variant provoking a marked thymic atrophy. Importantly, the changes in the immune responses correlated with the severity of infection. Our study provides a comprehensive platform to investigate the modulation of disease by SARS-CoV-2 variants and underscores the impact of this infection on the function of primary lymphoid organs.

Keywords: Components of the immune system; Immunology; Pathology; Virology.