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1.
Sci Immunol ; : eabo0535, 2022 Mar 10.
Article in English | MEDLINE | ID: covidwho-1736021

ABSTRACT

SARS-CoV-2 primarily replicates in mucosal sites, and more information is needed about immune responses in infected tissues. Here, we used rhesus macaques to model protective primary immune responses in tissues during mild COVID-19. Viral RNA levels were highest on days 1-2 post-infection and fell precipitously thereafter. 18F-fluorodeoxyglucose (FDG)-avid lung abnormalities and interferon (IFN)-activated monocytes and macrophages in the bronchoalveolar lavage (BAL) were found on days 3-4 post-infection. Virus-specific effector CD8+ and CD4+ T cells became detectable in the BAL and lung tissue on days 7-10, after viral RNA, radiologic evidence of lung inflammation, and IFN-activated myeloid cells had substantially declined. Notably, SARS-CoV-2-specific T cells were not detectable in the nasal turbinates, salivary glands, and tonsils on day 10 post-infection. Thus, SARS-CoV-2 replication wanes in the lungs of rhesus macaques prior to T cell responses, and in the nasal and oral mucosa despite the apparent lack of antigen-specific T cells, suggesting that innate immunity efficiently restricts viral replication during mild COVID-19.

2.
J Exp Med ; 219(2)2022 02 07.
Article in English | MEDLINE | ID: covidwho-1565893

ABSTRACT

In addition to providing partial protection against pediatric tuberculosis, vaccination with bacille Calmette-Guérin (BCG) has been reported to confer nonspecific resistance to unrelated pulmonary pathogens, a phenomenon attributed to the induction of long-lasting alterations within the myeloid cell compartment. Here, we demonstrate that intravenous, but not subcutaneous, inoculation of BCG protects human-ACE2 transgenic mice against lethal challenge with SARS-CoV-2 (SCV2) and results in reduced viral loads in non-transgenic animals infected with an α variant. The observed increase in host resistance was associated with reductions in SCV2-induced tissue pathology, inflammatory cell recruitment, and cytokine production that multivariate analysis revealed as only partially related to diminished viral load. We propose that this protection stems from BCG-induced alterations in the composition and function of the pulmonary cellular compartment that impact the innate response to the virus and ensuing immunopathology. While intravenous BCG vaccination is not a clinically acceptable practice, our findings provide an experimental model for identifying mechanisms by which nonspecific stimulation of the pulmonary immune response promotes host resistance to SCV2 lethality.


Subject(s)
BCG Vaccine/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Administration, Intravenous , Angiotensin-Converting Enzyme 2/metabolism , Animals , Chemokines/metabolism , Humans , Inflammation/pathology , Mice, Inbred C57BL , Mice, Transgenic , Viral Load
3.
Sci Rep ; 11(1): 19458, 2021 09 30.
Article in English | MEDLINE | ID: covidwho-1447326

ABSTRACT

Efficacious therapeutics for Ebola virus disease are in great demand. Ebola virus infections mediated by mucosal exposure, and aerosolization in particular, present a novel challenge due to nontypical massive early infection of respiratory lymphoid tissues. We performed a randomized and blinded study to compare outcomes from vehicle-treated and remdesivir-treated rhesus monkeys in a lethal model of infection resulting from aerosolized Ebola virus exposure. Remdesivir treatment initiated 4 days after exposure was associated with a significant survival benefit, significant reduction in serum viral titer, and improvements in clinical pathology biomarker levels and lung histology compared to vehicle treatment. These observations indicate that remdesivir may have value in countering aerosol-induced Ebola virus disease.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , Ebolavirus/drug effects , Hemorrhagic Fever, Ebola/drug therapy , Adenosine Monophosphate/administration & dosage , Adenosine Monophosphate/pharmacology , Administration, Intravenous , Aerosols , Alanine/administration & dosage , Alanine/pharmacology , Animals , Antiviral Agents/administration & dosage , Disease Models, Animal , Female , Hemorrhagic Fever, Ebola/blood , Kaplan-Meier Estimate , Liver/drug effects , Liver/virology , Lung/pathology , Lung/virology , Lymph Nodes/drug effects , Lymph Nodes/pathology , Lymph Nodes/virology , Macaca mulatta , Male , Random Allocation , Systemic Inflammatory Response Syndrome/drug therapy , Systemic Inflammatory Response Syndrome/virology , Viral Load/drug effects , Viremia/drug therapy
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