Summary

Bioluminescent Bacterial Imaging In Vivo

Published: November 04, 2012
doi:

Summary

This article describes the administration of lux-tagged bacteria to mice and subsequent in vivo analysis using IVIS bioluminescence imaging.

Abstract

This video describes the use of whole body bioluminesce imaging (BLI) for the study of bacterial trafficking in live mice, with an emphasis on the use of bacteria in gene and cell therapy for cancer. Bacteria present an attractive class of vector for cancer therapy, possessing a natural ability to grow preferentially within tumors following systemic administration. Bacteria engineered to express the lux gene cassette permit BLI detection of the bacteria and concurrently tumor sites. The location and levels of bacteria within tumors over time can be readily examined, visualized in two or three dimensions. The method is applicable to a wide range of bacterial species and tumor xenograft types. This article describes the protocol for analysis of bioluminescent bacteria within subcutaneous tumor bearing mice. Visualization of commensal bacteria in the Gastrointestinal tract (GIT) by BLI is also described. This powerful, and cheap, real-time imaging strategy represents an ideal method for the study of bacteria in vivo in the context of cancer research, in particular gene therapy, and infectious disease. This video outlines the procedure for studying lux-tagged E. coli in live mice, demonstrating the spatial and temporal readout achievable utilizing BLI with the IVIS system.

Protocol

1. Tumor Induction For routine tumor induction, the minimum tumorigenic dose of cells suspended in 200 μl of serum-free culture medium was injected subcutaneously (s.c.) into the flank of infection free 6-8 week old female Balb/C or athymic MF1-nu/nu mice n=6 (Harlan, Oxfordshire, UK) (1 x 106 4T1 cells) using a 21-gauge syringe needle. The viability of cells used for inoculation was greater than 95 % as determined by visual count using a haemocytometer and Trypan Blue Dye Exclusion (Gibco). <…

Discussion

In the context of gene therapy, the use of biological agents for delivery of therapeutic genes to patients has shown great promise 3-5. Like viruses, the innate biological properties of bacteria permit efficient DNA delivery to cells or tissues, particularly in the context of cancer. It has been shown that bacteria are naturally capable of homing to tumors when systemically administered resulting in high levels of replication locally, either external to (non-invasive species) or within tumor cells (pathogens)….

Divulgaciones

The authors have nothing to disclose.

Acknowledgements

The authors wish to acknowledge support relevant to this manuscript from the European Commission Seventh Framework Programme (PIOF-GA-2009-255466) and the Irish Health Research Board (HRA_POR/2010/138). Lux-tagged E. coli was a kind gift from Dr. Cormac Gahan, University College Cork.

Materials

Name of the reagent Company Catalogue number Comments
4T1 cell line ATCC CRL-2539 Syngeneic breast cancer model derived from a spontaneously arising BALB/c mammary tumor
DMEM Sigma-Aldrich D6429 Dulbecco’s Modified Eagle’s Medium
PBS Sigma-Aldrich D8537 Phosphate Buffered Saline
Xenogen IVIS Caliper Life Sciences   IVIS 100 for 2D imaging; IVIS Spectrum for 3D.
Luria Broth Miller (LB) Sigma-Aldrich L2542 Growth medium for E. coli
Erythromycin Sigma-Aldrich E5389 Antibiotic
Streptomycin Sigma-Aldrich S9137 Antibiotic
MF1nu/nu mice Harlan (UK) 069(nu)/070(nu/+) Hsd:Athymic Nude-Foxn1nu
Balb/c mice Harlan (UK) 066 Haplotype: H-2d
Gavage needle Vet-tech Solutions (UK) DE009 22G x 38mm straight gavage needle
Syringe for IV injection BD BioSciences 309309 – 1 ml Insulin syringe with 28 G x ½ inch micro-fine IV needle.
Syringe for tumor inoculation Braun 9161376V Omnifix 26 G x ½ inch needle

Referencias

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Baban, C. K., Cronin, M., Akin, A. R., O’Brien, A., Gao, X., Tabirca, S., Francis, K. P., Tangney, M. Bioluminescent Bacterial Imaging In Vivo. J. Vis. Exp. (69), e4318, doi:10.3791/4318 (2012).

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