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Influenza B Virus (Strain: Brisbane/33/08)
The Influenza B Virus (Strain: Brisbane/33/08) is a laboratory-adapted virus strain from the B/Victoria lineage, isolated in Brisbane, Australia, in 2008. It is widely used as a reference material in influenza research, diagnostic assay validation, vaccine quality control, and virus neutralization studies.
This product is supplied in a 1 mL volume, typically at a defined infectious titer (e.g., ≥10⁶ TCID₅₀/mL), suspended in a suitable viral transport medium or phosphate-buffered saline. The virus is propagated in MDCK (Madin-Darby Canine Kidney) cells, a standard host line for influenza virus amplification.
Technical Characteristics
| Feature | Description |
|---|---|
| Virus Family | Orthomyxoviridae |
| Genome | Segmented, negative-sense, single-stranded RNA |
| Strain Name | B/Brisbane/33/2008 |
| Lineage | B/Victoria |
| Passage History | Typically low-passage, MDCK-amplified |
| Formulation | Liquid suspension |
| Volume | 1 mL |
| Titer (approx.) | ≥10⁶ TCID₅₀/mL (batch-specific) |
| Biosafety Level | BSL-2 |
| Storage | -80°C; avoid freeze-thaw cycles |
Genome Structure
The Influenza B virus contains 8 RNA segments coding for:
- Hemagglutinin (HA) – major surface glycoprotein, binds to sialic acid on host cells.
- Neuraminidase (NA) – releases progeny virions.
- Polymerase complex (PB1, PB2, PA) – RNA-dependent RNA polymerase components.
- Nucleoprotein (NP) – encapsidates the RNA segments.
- Matrix (M1, M2) – viral structure and ion channel activity.
- Non-structural proteins (NS1, NS2) – host immune modulation and nuclear export.
The HA gene of Brisbane/33/08 shows amino acid changes from previous B/Victoria strains, making it important for evaluating immune escape and antigenic drift.
Applications
- Reference Strain for Vaccine Studies: Used in hemagglutination inhibition (HI) and microneutralization assays to test vaccine-induced antibodies.
- Molecular Assay Development: Calibration of qRT-PCR primers and probes for Influenza B lineage discrimination.
- Antiviral Screening: In vitro models for assessing candidate compounds against Influenza B replication.
- Serological Assays: Used in ELISA and lateral flow formats for B/Victoria antigen detection.
- Infectivity Testing: Standard for quantifying TCID₅₀ or PFU in controlled infection models.
Handling Guidelines
- Thaw on ice immediately before use.
- Gently mix without vortexing to maintain viral particle integrity.
- Use biosafety cabinet and BSL-2 practices.
- Aliquot post-thaw if repeat use is expected to avoid freeze-thaw damage.
- Dispose using validated viral inactivation protocols.
Storage and Stability
- Long-term storage at -80°C.
- Stable for up to 12 months if unopened and correctly frozen.
- Avoid >2 freeze-thaw cycles to maintain infectivity.
- If diluted, store working solution at 4°C and use within 24 hours.
Documentation and Testing
- Sterility-tested (mycoplasma, bacterial/fungal contamination)
- Titer determined via TCID₅₀, plaque assay, or qPCR.
- Genetic identity confirmed via segmental RT-PCR and Sanger or NGS sequencing.
- Certificate of Analysis (CoA) provided with each batch.
Use Restrictions
- For research use only (RUO).
- Not for diagnostic or therapeutic purposes.
- Not for use in human or animal subjects.
