RESUMEN
It is postulated that vaccination against tuberculosis with Bacillus Cal-mette-Gue'rin (BCG) vaccine may translate into lower incidence of respiratory tract infections by modulating the release of pro-inflammatory cytokines by innate immune cells. This modulation may be due to epigenetic changes in these cells resulting in an increase in the production of pro-inflammatory cytokines such as IL-1 beta, IL-6 or TNF-alpha. It is not known whether the pulmonary vascular endothelium equip-ped with molecular pattern recognition receptors (PRRs) and with en-try receptors for human coronaviruses can be infected by them, or whether BCG vaccination may modulate its susceptibility to infection with these viruses. This study analyzes the effect of the HCoV 229E human coronavirus on human pulmonary vascular endothelium. Mo-reover, the influence of BCG sonicates on susceptibility to HCoV 229E endothelial infection and the generation of antiviral and inflammatory responses was assessed.
RESUMEN
The Coronaviridae family includes the seven known human coronavi-ruses (HCoV) that cause mild to moderate respiratory infections (HCo-V-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU1) as well as severe illness and death (MERS-CoV, SARS-CoV, SARS-CoV-2). Severe infections in-duce inflammatory responses that are often intensified by host ada-ptive immune pathways. Proinflammatory responses are triggered by CoV entry mediated by host cell surface receptors. Interestingly, four of the seven strains use cell surface metallopeptidases as receptors. The entry receptors for specific coronaviruses are: aminopeptidase N (AP-N), dipeptidyl peptidase 4 (DPP4) and angiotensin-converting enzyme 2 (ACE2) for HCoV-229E, MERS-CoV, SARS-CoV and SARS-CoV2, respectively. In addition, these receptors perform many physiological functions, including the regulation of the circulatory and immune sys-tems. Coronavirus receptors are also highly expressed in human tissues and organs (intestines, kidneys, heart, lungs). Additionally, some cy-tokines, chemokines, and other proteins and immune cells influence the modulation of the expression of coronavirus receptors. This review presents the biological role of receptor proteins in the regulation of human physiological systems, the impact of the immune response on susceptibility to coronavirus infections, and the potential effects of glucocorticosteroids (GCS) and specific allergen immunotherapy (AIT) used in the treatment of asthma and allergy on the suscpetibility to coronaviral infections.