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- Aquatic Vertebrate Models
- Nonhuman Primate Models
Modified Adenovirus Prime–Protein Boost Clade C HIV Vaccine Strategy Results in Reduced Viral DNA in Blood and Tissues Following Tier 2 SHIV Challenge
Malherbe et al., Frontiers in Immunology. 2021.
https://doi.org/10.3389/fimmu.2020.626464
Researchers conducted a comparative vaccine challenge study in rhesus macaques. One group of monkeys was vaccinated using co-immunization with DNA Gag and Env expression plasmids and trimeric Env gp140 glycoprotein. The other group was primed with two replicating simian adenovirus-vectored vaccines expressing Gag and boosted with trimeric Env gp140. Both strategies elicited antigen-specific humoral and cellular immune responses, but neither approach provided significant protection from viral acquisition upon repeated mucosal challenges with a heterologous Tier 2 SHIV. Nevertheless, both regimens significantly lowered cell-associated viral DNA in multiple tissues, thus potentially dampening the infection and providing clues for further vaccine development. Supported by ORIP (U42OD023038, P51OD011092) and NIAID.
Evaluating a New Class of AKT/mTOR Activators for HIV Latency-Reversing Activity Ex Vivo and In Vivo
Gramatica et al., Journal of Virology. 2021.
https://doi.org/10.1128/JVI.02393-20
Activation of latent HIV-1 expression could benefit many HIV cure strategies. Researchers evaluated two AKT/mTOR activators, SB-216763 and tideglusib, as a potential new class of LRAs. The drugs reactivated latent HIV-1 present in blood samples from aviremic individuals on antiretroviral therapy without causing T cell activation or impaired effector function of cytotoxic T lymphocytes or NK cells. When tested in vivo in monkeys, tideglusib showed unfavorable pharmacodynamic properties and did not reverse SIV latency. The discordance between the ex vivo and in vivo results underscores the importance of developing novel LRAs that allow systemic drug delivery to relevant anatomical compartments. Supported by ORIP (P51OD011092), NIAID, NIGMS, NIMH, and NCI.
BNT162b Vaccines Protect Rhesus Macaques from SARS-CoV-2
Vogel et al., Nature. 2021.
https://www.nature.com/articles/s41586-021-03275-y
The preclinical development of two BNT162b vaccine candidates, which contain lipid-nanoparticle formulated nucleoside-modified mRNA encoding SARS-CoV-2 spike glycoprotein-derived immunogens, was performed in rhesus macaques at the Southwest National Primate Research Center (SNPRC). BNT162b1 encodes a soluble, secreted, trimerised receptor-binding domain. BNT162b2 encodes the full-length transmembrane spike glycoprotein, locked in its prefusion conformation. Prime/boost vaccination of rhesus macaques with BNT162b candidates elicits SARS-CoV-2 neutralizing antibody titers that are 8.2 to 18.2 times that of a SARS-CoV-2 convalescent human serum panel. The vaccine candidates protected macaques from SARS-CoV-2 challenge, with BNT162b2 protecting the lower respiratory tract from the presence of viral RNA and with no evidence of disease enhancement. The BNT162b2 vaccine recently received emergency use authorization from FDA and is being administered within the United States. The SNPRC is supported by ORIP (P51OD011103).
Trim-Away Mediated Knock Down Uncovers a New Function for Lbh During Gastrulation of Xenopus laevis
Weir et al., Developmental Biology. 2021.
https://pubmed.ncbi.nlm.nih.gov/33159936/
The protein Lbh was identified as necessary for cranial neural crest cell migration in Xenopus. To investigate its role in embryonic events, the authors employed the technique "Trim-Away" to degrade this maternally deposited protein. Trim-Away utilizes the E3 ubiquitin ligase trim21 to degrade proteins targeted with an antibody. Early knockdown of Lbh in Xenopus results in defects in gastrulation that present with a decrease in fibronectin matrix assembly, an increase in mesodermal cell migration and decrease in endodermal cell cohesion. The technique is also effective on a second abundant maternal Protein Kinase C And Casein Kinase Substrate In Neurons 2. Supported by ORIP (R24OD021485) and NIDCR.
Germline Transmission of Donor, Maternal and Paternal mtDNA in Primates
Ma et al., Human Reproduction. 2021.
https://doi.org/10.1016/j.immuni.2021.02.001
Mitochondrial gene mutations contribute to incurable human disorders. The possibility of using mitochondrial replacement therapy (MRT) to prevent transmission of pathogenic mitochondrial (mt)DNA was explored in rhesus macaques. Development of spindle MRT transfer in oocytes in 5 female rhesus macaques resulted in healthy and fertile offspring. These results demonstrate that MRT is compatible with normal postnatal development, including overall health and reproductive fitness in nonhuman primates with no detected adverse effects. Additional research is needed to more fully explore the use of MRT to prevent disorders as this study had a limited number of animals with only one female offspring. Supported by ORIP (P51OD0092) and NIA.
Modified Vaccinia Ankara Vector-Based Vaccine Protects Macaques from SARS-CoV-2 Infection, Immune Pathology and Dysfunction in the Lung
Routhu et al., Immunity. 2021.
https://doi.org/10.1016/j.immuni.2021.02.001
Any SARS-CoV-2 vaccine may have limitations such as need for ultracold storage, poor induction of CD8+ T cell response, or lack of cross-reactivity with emerging strains. Thus, multiple vaccines may be needed to bring COVID-19 under control. Using rhesus macaques, researchers showed that a modified vaccinia Ankara (MVA) vector-based SARS-CoV-2 vaccine expressing prefusion-stabilized spike protein induced strong neutralizing antibody and CD8+ T cell responses. The vaccine protected macaques from SARS-CoV-2 infection as well as infection-induced inflammation and B cell abnormalities in the lung. These results are promising considering the excellent safety and performance of MVA vector-based vaccines for other pathogens. Supported by ORIP (P51OD011132, S10OD026799) and NIAID.
SARS-CoV-2 Induces Robust Germinal Center CD4 T Follicular Helper Cell Responses in Rhesus Macaques
Lakshmanappa et al., Nature Communications. 2021.
https://www.nature.com/articles/s41467-020-20642-x
SARS-CoV-2 infection in both sexes of rhesus macaques, either infused with convalescent plasma, normal plasma, or receiving no infusion, resulted in transient accumulation of pro-inflammatory monocytes and proliferating CD4 T follicular helper (Tfh) cells, which are critical for persistent antibody responses. CD4 helper cell responses skewed predominantly toward a Th1 response in blood, lung, and lymph nodes. This skewing is important to note, as weak interferon responses observed in COVID patients could hamper effective antiviral antibody and CD8 T-cell responses. Collectively, the data show induction of GC responses in a rhesus model of mild COVID-19. Supported by ORIP (P51OD011107 and P40OD010976) and NIAID.
Endogenous Zebrafish Neural Cre Drivers Generated by CRISPR/Cas9 Short Homology Directed Targeted Integration
Almeida et al., Scientific Reports. 2021.
https://pubmed.ncbi.nlm.nih.gov/33462297/
Almeida et al. previously reported precision targeted integration of reporter DNA in zebrafish using CRISPR/Cas9. Here, they isolated zebrafish Cre recombinase drivers. A 2A-Cre recombinase transgene with 48 bp homology arms was targeted into proneural genes ascl1b, olig2 and neurod1. They observed high rates of germline transmission from 10 to 100% (10% olig2; 20% neurod1; 100% ascl1b). The lines Tg(ascl1b-2A-Cre)is75, Tg(olig2-2A-Cre)is76, and Tg(neurod1-2A-Cre)is77 expressed functional Cre recombinase in the cell populations. Results demonstrate Cre recombinase expression is driven by the native promoter and regulatory elements of targeted genes. This approach is a cost-effective method to generate cell type specific zebrafish Cre and CreERT2 drivers. Supported by ORIP (R24OD020166).
Myelin‐Specific T Cells in Animals With Japanese Macaque Encephalomyelitis
Govindan et al., Annals of Clinical and Translational Neurology. 2021.
https://onlinelibrary.wiley.com/doi/10.1002/acn3.51303
Investigators characterized the CD4+ and CD8+ T cells in demyelinating Japanese macaque encephalomyelitis (JME) lesions in age‐ and sex‐matched macaques and discovered differences in expression of myelin antigen sequences in the T cell. Mapping myelin epitopes revealed a heterogeneity in T cell responses among JME animals, which are associated with a proinflammatory pathogenic role in multiple sclerosis (MS). These findings draw further parallels between JME and MS and support the hypothesis that JME and possibly MS are triggered by mechanisms involving myelin damage and not myelin epitope mimicry. Supported by ORIP (P51OD011092) and NINDS.
Thresholds for Post-Rebound SHIV Control after CCR5 Gene-Edited Autologous Hematopoietic Cell Transplantation
Cardozo-Ojeda et al., eLife. 2021.
https://elifesciences.org/articles/57646
Investigators developed a mathematical model to project the minimum threshold of C-C chemokine receptor type 5 (CCR5) gene-edited cells necessary for a functional cure from HIV. This was based on blood T cell reconstitution and plasma simian-HIV (SHIV) dynamics from SHIV-1157ipd3N4-infected juvenile pig-tailed macaques that underwent autologous transplantation with CCR5 gene editing. The model predicts that viral control can be obtained following analytical treatment interruption (ATI) when: (1) transplanted hematopoietic stem and progenitor cells (HSPCs) are at least fivefold higher than residual endogenous HSPCs after total body irradiation and (2) the fraction of protected HSPCs in the transplant achieves a threshold (76–94%) sufficient to overcome transplantation-dependent loss of SHIV immunity. Under these conditions, if ATI is withheld until transplanted gene-modified cells engraft and reconstitute to a steady state, spontaneous viral control is projected to occur. Supported by ORIP (P51OD010425), NCATS and NIAID.