hACE2 upregulation and participation of macrophages and clear cells in the immune response of epididymis to SARS-CoV-2 in K18-hACE2 mice.

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus caused the coronavirus disease 2019 pandemic, and the prevalence of deaths among men is higher than among women. The epididymis, divided into caput, corpus, and cauda, shows a region-specific immunity. The K18-hACE2 mouse expresses human angiotensin-converting enzyme 2 (hACE2), the receptor that allows SARS-CoV-2 infection.