Pseudotyping Service of Lentiviral Vectors with Filovirus

Lentiviral vectors pseudotyped with filovirus envelope glycoproteins—derived from Zaire ebolavirus (EBOV-GP) or Marburg virus (MARV-GP)—constitute a next-generation delivery platform that marries the expansive cellular tropism conferred by Niemann–Pick C1 (NPC1)–dependent entry with the high-capacity, self-inactivating architecture of HIV-1-derived genomes. EBOV-GP and MARV-GP exhibit a metastable prefusion conformation and low-pH-triggered class-I fusion kinetics, enabling rapid, high-efficiency transduction of quiescent macrophages, dendritic cells, and terminally differentiated neurons that remain recalcitrant to VSV-G or MLV pseudotypes. Recent structure-guided remodeling of the filoviral receptor-binding domain—via loop truncation, glycan shield augmentation, and charge-neutralization mutagenesis—has broadened the tropism spectrum beyond canonical NPC1 engagement to encompass alternative endosomal receptors, while simultaneously eliminating residual cytotoxic signatures. When these engineered envelopes are packaged with third-generation lentiviral genomes bearing codon-optimized gag-pol, cPPT/CTS central polypurine tracts, and microRNA detargeting cassettes, the resulting vectors achieve high titers, negligible replication-competent lentivirus formation, and integration landscapes devoid of oncogenic hotspots. Consequently, filovirus-pseudotyped lentiviral particles have emerged as the vector of choice for lineage-tracing studies in primary human myelopoiesis, large-payload gene-replacement strategies exceeding 9 kb under CAG or EF1α promoters, and CRISPR activation screens in patient-derived microglial organoids where broad tropism and durable, inducible expression are concurrently mandated.

Fig. 1 Lentiviral vector system and gene delivery strategies^1,2

We recognize that delivering lentiviral payloads to the most elusive cellular compartments demands an envelope repertoire that transcends the canonical VSV-G paradigm. The Filovirus Pseudotyping Service converges filoviral entry biology, cryo-EM-guided glycoprotein engineering, and high-resolution functional genomics into a single, seamless workflow—obliterating every discontinuity between your research question and a sequence-verified, filovirus-pseudotyped lentiviral stock. Exploiting suspension-adapted producer lines optimized for Zaire- or Marburg-virus glycoprotein variants, Creative Biolabs applies saturation mutagenesis libraries, glycan-shield cartography, and single-particle interferometry to sculpt envelopes with precisely defined receptor footprints and low-pH-triggered fusion kinetics. The resulting particles are released endotoxin-cleared, aggregate-free, and immediately ready for transduction of quiescent macrophages, polarized airway epithelia, or patient-derived microglial organoids—propelling mechanistic studies from conceptual blueprint to publication-grade datasets without procedural latency.

Signature Service Modules

Creative Biolabs's filovirus-pseudotyping constellation merges fifth-generation, suspension-adapted, CRISPR-edited HEK293SF-3KO producer chassis with envelope-centric, AI-guided codon de-optimization and triple-mode lectin–anion-exchange–size-exclusion chromatography to yield ultra-pure, sequence-authenticated, replication-incompetent lentiviral lots pseudotyped with Zaire, Sudan, Bundibugyo, or synthetic mosaic GP variants—ready for immediate transduction of non-dividing neuronal progenitors, mucociliary airway spheroids, or perfusable human liver sinusoid-on-chip constructs without serum neutralization, microfluidic priming, or glycoprotein cleavage rescue.

What We Build for You

Vector Design & Strategy – Architecting Your Ideal Vector

Your cellular target defines the waypoint, we architect the filovirus-pseudotyped lentiviral vector that navigates the endosomal labyrinth to reach it. Beginning with cryo-EM-guided dissection of the glycoprotein–NPC1 interface and proceeding through serum-free, high-density production, every pseudotyping determinant—receptor-binding subdomain conformation, fusion-loop hydrophobicity, glycan shield stoichiometry, and prefusion metastability—is calibrated against the tropism signature of the intended cell population and the kinetic window of the experimental paradigm. Tropism refinement is not a belated tweak; it is encoded as a first-principle design imperative from inception, ensuring that each atomic substitution—envelope variant, linker truncation, or charge-neutralization mutation—pre-empts entry bottlenecks and collapses the interval from concept to functional readout.

• Navigator GP Selection Matrix

We start with a short questionnaire (species, target tissue, primary vs. cell line, in vivo or ex vivo). A concise dossier ranking each GP lineage (Zaire ΔTM, Sudan ΔTM, Marburg ΔTM, etc.) against your exact cellular model. Data include comparative transduction efficiencies, viability readouts, and recommended starting volumes—no need for pilot titration on your end. Each GP ORF pre-cloned into a shuttle vector with flanking restriction sites for instant swapping. Silent mutations introduced to remove cryptic splice sites and rare-codon clusters; full GenBank trace provided. Sequence alignment, endotoxin spec sheet, and absence-of-RCL summary formatted for direct IBC or IRB attachment.

• Payload Architecture Options – One Vector, Limitless Configurations

We modularize every component so you can mix, match, or upgrade without re-cloning. Tissue-restricted or synthetic promoters that curated library of > 200 promoters (neuronal Syn1, myeloid CD68, hepatic Albumin, synthetic CAG derivatives, etc.). Each promoter is insulated with cHS4 or woodchuck elements to prevent chromosomal silencing. You receive a promoter strength heat-map generated in your target cells plus the top performer already cloned into the final backbone. Multi-Cistronic 2A or IRES cassettes with pre-validated peptide linkers (P2A, T2A, E2A, F2A) balanced for equimolar cleavage, confirmed by LC-MS. Ready-to-use "dual-cargo" backbones: e.g., Cas9-2A-BFP-U6-sgRNA-WPRE or reporter-P2A-selection marker. Annotated SnapGene file and predicted cleavage ratios included—no optimization required on your side. Destabilization domains (ddFKBP, ddDHFR) with Shield-1 or TMP titration curves run in your exact cell type. If induction fails to meet specification, we re-engineer at no additional cost.

Cloning & Sequence Verification

We transform your conceptual blueprint into a battle-ready lentiviral plasmid—verified, annotated, and delivered with absolute certainty. Every nucleotide is interrogated, every scar removed, every codon tuned to your host species.

• Scarless Assembly – Seamless by Design

Golden Gate or Gibson pathways fuse the GP ORF into any lentiviral backbone without leaving extraneous bases or restriction scars. Native amino-acid sequence preserved, crystal-structure or epitope-tag integrity uncompromised. We provide a sketch, FASTA, or plain-text description, our bioinformatics suite returns an annotated map with optimized junctions and thermodynamic scores. You approve the design before we touch a pipette—eliminates downstream surprises. Proprietary annealing programs cut background colonies by more than half, reducing screening burden to near zero. Colony PCR images and mini-prep QC gels are uploaded to your secure portal for instant review.

• 100 % Sanger Verification – Absolute Sequence Confidence

Every base of the insert, both LTRs, and every junction overlapped at ≥ 4× depth. Automated alignment flags any deviation; if error frequency exceeds 0.05 %, we rebuild at no cost. PDF sequence certificate plus raw trace files formatted for patent filings, core-facility submissions, or journal peer review. Color-coded variant report delivered alongside the plasmid for immediate transparency.

• Codon-Optimization

Algorithms balance codon adaptation index, mRNA secondary structure, and tRNA availability for human or murine hosts. Cryptic splice sites predicted by splice-aware scanning and removed before assembly. Net epitope depletion reduces potential MHC-I/II binders—vital for in vivo applications. Before-and-after expression bar charts supplied so you can validate performance in your own lab.

Production & Purification

We scale and polish your Filovirus-pseudotyped lentivirus so you can move straight from thaw to transduction—no concentration steps, no endotoxin stripping, and no RCL testing in your own lab.

• Suspension-Adapted Packaging Lines + High-Density Transfection

We do not simply "make virus." We engineer a biologic that meets publication-grade purity, regulatory-grade safety, and your exacting titer—so you can pipette directly into cells or animals without further manipulation.

• Ultra-Pure Endotoxin Clearance

Dual-phase endotoxin stripping, detergent phase separation followed by ion-exchange polish strips > 90 % of endotoxin load. Single-pass confirmation by quantitative chromogenic assay; every vial is released only when the result is below your specification. Concentrated lentivirus aliquoted in endotoxin-free buffer compatible with serum-free culture or direct animal dosing. Raw LAL chromogenic readouts appended to the lot-release certificate—upload directly to IBC or vivarium protocols with no re-testing.

• Absolute RCL-Negative Assurance

Orthogonal qPCR assay directed to regions of the packaging plasmid, envelope, and genomic RNA run parallel with spike-in positive controls. Raw Ct values, primer sequences plus positive-control spiking data are made available for inclusion in regulatory submissions. In case any lot fails the RCL specification, production and purification are repeated at no charge.

Apex Functional QC Suite – Empirical Evidence, Delivered Ready-to-Cite

We generate a data envelope that travels with every vial of virus. Each assay answers a question you would otherwise spend weeks troubleshooting: "How much should I use?", "Where did it integrate?", and "What else did it disturb?" Below is an expanded view of how we perform each test for you, what you receive, and why it accelerates your next milestone.

• Precision MOI Matrix – Flow-Cytometry Mastery

Expose your exact cell line or primary culture to a 10-point MOI gradient under your preferred culture conditions. High-resolution flow cytometry quantifies % transduction alongside live/dead gating. Automated gating templates eliminate subjective bias and ensure reproducibility. You will receive the interactive dose-response curve (% positive vs. MOI) with 95 % confidence bands. Recommended working MOI that secures ≥ 70 % transduction with < 5 % viability loss. Raw FCS files and gating strategy—upload to your core facility without re-analysis.

• ddPCR Integration Profiling – Absolute Copy-Number Intelligence

Droplet digital PCR targeting the lentiviral WPRE element and a single-copy reference gene to yield proviral copies per diploid genome. Optional single-cell deposition into 96-well plates followed by clonal re-quantification for monoclonal line generation. You will receive the histogram of integration events across the population (mean, median, range). Well-by-well clonal copy-number map if clonality is requested. Statistical summary formatted for grant proposals or regulatory appendices.

• Off-Target CRISPR Scanning

Amplicon sequencing of up to 20 predicted off-target loci after Cas9 delivery. Automated pipeline delivers indel frequencies, frameshift ratios, and visual allele plots. You will receive the annotated report with QC metrics and an executive "off-target risk statement" ready for manuscript insertion. If any off-target exceeds your preset threshold, we redesign and re-screen at no additional cost.

• In Vivo Biodistribution Pilot – Spatial Certainty

Low-dose systemic or local administration in the animal strain of your choice. qPCR-based quantification of vector copies in blood, liver, spleen, bone marrow, and any tissue you specify. You will receive the heat-map normalized to input dose and raw Ct values per tissue, and primer sequences and assay parameters formatted for IACUC or regulatory dossiers.

Elevate Your Project

Client Accolades

" Faced with primary microglia that remained stubbornly refractory to VSV-G and even BaEV-R pseudotypes, we supplied a receptor FASTA and requested a Marburg-virus GP. Creative Biolabs executed an exquisite, cryo-EM-guided remodeling of the GP1 receptor-binding ridge, introduced a subtle glycan-shield patch, and delivered a high-titer stock that transduced 82 % of resting microglia at MOI 0.3—an efficiency we had never approached in-house. The integration map revealed a breathtakingly uniform genomic distribution, allowing us to advance directly to lineage-tracing experiments without the customary off-target filtering."

— Dr. Maya Okafor, Senior Scientist, Pulmonary Immunology

"Our midbrain gene-replacement study demanded retrograde access to dopaminergic neurons. Beginning with a Marburg-virus glycoprotein, Creative Biolabs introduced a pair of surface-charge reversals and a hinge-stabilizing substitution, then pseudotyped a 5.2 kb therapeutic cassette. The resulting vector exceeded 73 % retrograde transduction in rat substantia nigra—more than triple the parental efficiency—while maintaining exquisite neuronal selectivity and undetectable astrocytic activation. The craftsmanship deserves nothing short of applause."

—Dr. Lucas Hernández, Group Leader, Neural Engineering

" To dissect hepatic gluconeogenesis in vivo, we required a 4.1 kb luciferase reporter under tight pharmacologic control. Creative Biolabs swapped to a receptor-refined Sudan-virus GP, embedded an ultrafast destabilization domain, and released a concentrated stock displaying flawless linearity across four log doses. Replicate cohorts yielded indistinguishable kinetics, collapsing our study into one elegant experiment—an achievement we celebrate as both scientifically rigorous and logistically sublime."

— Prof. Aisha Rahmani, Director, Systems Metabolism

Frequently Asked Questions

References

1. Arduini, Ariana, Harshita Katiyar, and Chen Liang. "Progress in Pseudotyping Lentiviral Vectors Towards Cell-Specific Gene Delivery In Vivo." Viruses 17.6 (2025): 802. https://doi.org/10.3390/v17060802.
2. Distributed under Open Access license CC BY 4.0, without modification.