Creative biogene
SHARE THIS
facebook twitterlinkedingoogle plusStumbleUpon blog


Frequently Asked Questions: Custom Virus Service

email info@creative-biogene.com Tel: 1-631-626-9181 Fax: 1-631-614-7828

1. There are several viral gene delivery systems, including adenovirus, retrovirus and lentivirus. Which one should I use for my experiments?
2. What is the required biosafety level for using recombinant viruses?
3. What are the recommended storage conditions of recombinant viruses?
4. What are the differences between viral particle (VP), plaque formation unit (PFU) and infectious unit (IFU)? Which one of these better reflects the amount of active virus used?
5. There are many serotypes of adenoviruses, which one is the most commonly used for gene delivery?
6. Which serotype should I use in my experiment?
7. What is the difference between a lentivirus and a retrovirus?
8. What is the difference between 2nd generation and 3rd generation lentiviral systems?


1. There are several viral gene delivery systems, including adenovirus, retrovirus and lentivirus. Which one should I use for my experiments?

1) Retrovirus: requires active cell division. In addition, there is a significant risk of integration into the host genome, leading to mutation of genes or activation of onco-genes in the host system, which is a concern for scientists.
2) Lentivirus: can infect both dividing and non-dividing cells. Like retrovirus, there is a significant risk of integration into the host genome, leading to mutation of genes or activation of oncogenes in the host system.
3) Adenovirus: 100% gene delivery efficiency in most cell types including dividing and non-dividing or primary cells. There is no integration with the host system.
4) AAV: has the capacity to produce high titer virus with broad spectrum of tropism in dividing and non-dividing cells and potential for long-term gene transfer with minimum immnunogenicity.

2. What is the required biosafety level for using recombinant viruses?

The recombinant viruses we made are all replication deficient. According to references issued by the NIH Office of Biosafety, recombinant viruses have been classified in biosafety level II for agents considered of ordinary potential harm, and you need BL-2 level facility to work with it.

3. What are the recommended storage conditions of recombinant viruses?

The virus stock should be aliquoted upon receipt and stored at -80°C, especially after CsCl or chromatography purification. Repeated freeze-and-thaw should be avoided, since it will cause significant decrease of titer.

4. What are the differences between viral particle (VP), plaque formation unit (PFU) and infectious unit (IFU)? Which one of these better reflects the amount of active virus used?

1) PFU (plaque formation unit) represents the number of infectious or live viruses. It reflects the amount of working viruses in the preparation.
2) IFU (infectious unit) is equivalent to PFU.
3) Viral particles (VPs) represent the total number of viral particles (live and dead combined). Due to variations in virus preparations the ratio of live/dead varies significantly and therefore, VP does not reflect the amount of active virus in the preparation.

5. There are many serotypes of adenoviruses, which one is the most commonly used for gene delivery?

We routinely use human adenovirus serotype 5 (DE1/E3) which is the most commonly used adenovirus for gene delivery.

6. Which serotype should I use in my experiment?

Based on published literatures, below are some preliminary guidelines:
AAV1: CNS, Eye, Heart, Lung, Skeletal muscle
AAV2: CNS, Eye
AAV5: CNS, Eye, Lung
AAV6: Adipose, Heart, Liver, Lung, Skeletal muscle
AAV8: Adipose, CNS, Eye, Liver, Skeletal muscle;
AAV9: Adipose, CNS, Eye, Heart, Liver, Lung, Skeletal muscle

7. What is the difference between a lentivirus and a retrovirus?

Lentiviruses are a subtype of retrovirus. From an experimental standpoint the main difference between lentiviruses and standard retroviruses (γ-retroviruses) is that lentiviruses are capable of infecting non-dividing and actively dividing cell types whereas standard retroviruses can only infect mitotically active cell types. This means that lentiviruses can infect a greater variety of cell types than retroviruses.

8. What is the difference between 2nd generation and 3rd generation lentiviral systems?

Briefly, 2nd generation lentiviral systems use more HIV proteins (on fewer plasmids) in order to produce functional lentiviral particles than 3rd generation systems. Third generation lentiviral systems are considered safer than second generation systems, but may be more difficult to use because they require transfection with four separate vectors in order to create functional lentiviral particles. A 3rd generation transfer vector can be used with a 2nd generation packaging system, but a 2nd generation transfer vector cannot be used with a 3rd generation packaging system.

Custom Viral Service
Services
Contact us to order
USA
45-1 Ramsey Road, Shirley, NY 11967, USA
Tel: 1-631-626-9181
Fax: 1-631-614-7828
Email: info@creative-biogene.com

Europe
Tel: 44-207-097-1828
Email: info@creative-biogene.com
CBpromise

24x7 CUSTOMER SERVICE

CONTACT US TO ORDER


CONTACT CREATIVE BIOGENE

45-1 Ramsey Road, Shirley, NY 11967, USA
Tel: 1-631-626-9181
Fax: 1-631-614-7828
Email: info@creative-biogene.com

Europe
Tel: 44-207-097-1828

Terms & Conditions | Privacy Policy | Sitemap | FAQ | © 2010-2018 Creative Biogene. All Rights Reserved.