Biology subjects

Rowe, L. A.

Publications and source records attributed to Rowe, L. A..

3 recordsLinked to original sources

bioRxiv2023

The Impact of SIV-Induced Immunodeficiency on Clinical Manifestation, Immune Response, and Viral Dynamics in SARS-CoV-2 Coinfection

Persistent and uncontrolled SARS-CoV-2 replication in immunocompromised individuals has been observed and may be a contributing source of novel viral variants that continue to drive the pandemic. Importantly, the effects of immunodeficiency associated with chronic HIV infection on COVID-19 disease and viral persistence have not been directly addressed in a controlled setting. Here we conducted a pilot study wherein two pigtail macaques (PTM) chronically infected with SIVmac239 were exposed to SARS-CoV-2 and monitored for six weeks for clinical disease, viral replication, and viral evolution, and compared to our previously published cohort of SIV-naive PTM infected with SARS-CoV-2. At the time of SARS-CoV-2 infection, one PTM had minimal to no detectable CD4+ T cells in gut, blood, or bronchoalveolar lavage (BAL), while the other PTM harbored a small population of CD4+ T cells in all compartments. Clinical signs were not observed in either PTM; however, the more immunocompromised PTM exhibited a progressive increase in pulmonary infiltrating monocytes throughout SARS-CoV-2 infection. Single-cell RNA sequencing (scRNAseq) of the infiltrating monocytes revealed a less activated/inert phenotype. Neither SIV-infected PTM mounted detectable anti-SARS-CoV-2 T cell responses in blood or BAL, nor anti-SARS-CoV-2 neutralizing antibodies. Interestingly, despite the diminished cellular and humoral immune responses, SARS-CoV-2 viral kinetics and evolution were indistinguishable from SIV-naive PTM in all sampled mucosal sites (nasal, oral, and rectal), with clearance of virus by 3-4 weeks post infection. SIV-induced immunodeficiency significantly impacted immune responses to SARS-CoV-2 but did not alter disease progression, viral kinetics or evolution in the PTM model. SIV-induced immunodeficiency alone may not be sufficient to drive the emergence of novel viral variants.

immunology↗

bioRxiv2023

Real time analysis of SARS-CoV-2 induced cytolysis reveals distinct variant-specific replication profiles

The continuous evolution of new SARS-CoV-2 variants with enhanced immune evasion capacity suggests the entire population is and will continue to be potentially vulnerable to infection despite pre-existing immunity. The ability of each new variant to evade host humoral immunity is the focus of intense research across the globe. Each variant may also harbor unique replication capabilities relevant for disease and transmission. Here we demonstrate the utility of a new approach to assessing viral replication kinetics using Real Time Cell Analysis (RTCA). Virus induced cell death is measured in real time by the detection of electrical impedance through cell monolayers. Using this system, we quantified replication kinetics of five clinically important viral variants; USA WA1/2020 (an A1 ancestral lineage isolate), Delta, and Omicron subvariants BA.1, BA.4, and BA.5. We identified multiple kinetic measures that proved useful in variant replication comparisons including time (in hours) to the maximum rate of cell death at each log10 viral dilution and the slope at the maximum rate of cell death. We found that WA1/2020 and Delta were the most rapid but in distinct ways. While WA1/2020 induced cell death most rapidly after inoculation, Delta was slightly slower to reach cell death, it appeared to kill cells faster once cytotoxic effects began. Interestingly, BA.1, showed substantially reduced replication kinetics relative to all other variants. Together, these data show that real time analysis of cell death is a robust method to assess replicative capacity of any given SARS-CoV-2 variant rapidly and quantitatively, which may be useful in assessment of newly emerging variants.

microbiology↗

bioRxiv2021

Intra-host SARS-CoV-2 evolution in the gut of mucosally-infected Chlorocebus aethiops (African green monkeys)

In recent months, several SARS-CoV-2 variants have emerged that enhance transmissibility and escape host humoral immunity. Hence, the tracking of viral evolutionary trajectories is clearly of great importance. Little is known about SARS-CoV-2 evolution in nonhuman primate models used to test vaccines and therapies and to model human disease. Viral RNA was sequenced from rectal swabs from Chlorocebus aethiops (African green monkeys) after experimental respiratory SARS-CoV-2 infection. Two distinct patterns of viral evolution were identified that were shared between all collected samples. First, mutations in the furin cleavage site that were initially present in the virus as a consequence of VeroE6 cell culture adaptation were subsequently lost in virus recovered in rectal swabs, confirming the necessity of this motif for viral infection in vivo. Three amino acid changes were also identified; ORF 1a S2103F, and spike D215G and H655Y, that were detected in rectal swabs from all sampled animals. These findings are demonstrative of intra-host SARS-CoV-2 evolution unique to this nonhuman primate species and may identify a host-adapted variant of SARS-CoV-2 that would be useful in future development of primate disease models.

microbiology↗