Immunomagnetic bead

Results from experiments using the protocol above27 have shown that anti-Salmonella immunomagnetic beads could be used to unambiguously determine the presence of Salmonella choleraesuis from suspensions of bacterial mixtures. This target organism was also positively identified from spiked samples of river water, human urine, chicken blood, and 1 % milk. For the river water and urine samples, no cross-reactivity was observed and only protein... 

Probably the most sensitive biosensor for rapid screening has been the ORIGIN electrochemiluminescence system (IGEN, Gaithersburg, MD). The primary reason for the ORIGIN S enhanced sensitivity is that it preconcentrates the target prior to the assay. Immunomagnetic beads are... 

Tu, S. 1., Uknalis, J., and Gehring, A. (1999). Detection of immunomagnetic bead captured Escherichia coli 0157 FI7 by light addressable potentiometric sensor. /. Rapid Methods Automat. Microbiol. 7, 69-79. 

Sorting of Human Peripheral Blood T-Cell Subsets Using Immunomagnetic Beads... 

Preparation of cells for use with either immunomagnetic beads preconjugated with MAbs or immunomagnetic beads coated with antimouse IgG antibodies... 

Ideal conditions for cell separation using immunomagnetic beads differ for the cell types and antibodies employed, and can only be identified by experimentation. This chapter gives sample protocols for isolating subsets of human peripheral blood T-cells and discusses technical points that may be of wider relevance to cell separation by this approach. 

Immunomagnetic beads Dynabeads M-450 coated with sheep antimouse IgG, sheep or rat antimouse IgG subclass (Fc-specific), or preconjugated with MAbs specific for CD4 and CD8 (available from Dynal, Wirral, Merseyside, UK) A broad range of other preconjugated beads are now supplied by Dynal and are summarized m Note 2. They will remain stable for up to 1 yr when stored at 2-8°C Thiomersal (0 01% [w/v]), or sodium azide (0.02% [w/v]) is used as preservative. Hazard warning Both sodium azide and thiomersal are irritants to the skm and eyes, and are toxic if inhaled or ingested. Handle with care. 

Positive Selection Using Immunomagnetic Beads (see Notes 7 and 8)... 

Hansen, T. and Hannestad, K. (1989) Direct HLA typing by rosetting with immunomagnetic beads coated with specific antibodies. J. Immunogenet. 16,137—139. 

Widjojoatmodjo, M. N., Fluit, A. C, Torensma, R, and Verhoef, J (1993) Comparison of immunomagnetic beads coated with protein A, protein G, or goat antimouse immunoglobulins. J. Immunol Methods 165, 11-19... 

Schwella, N, Zingsen, J., and Eckstein, R. (1992) Effective derosettmg of mononuclear cells isolated by immunomagnetic beads Infusionstherapie 19, 149—150... 

Geretti, A. M., van Els, C A C M, Poelen, M. C. M, and Osterhaus, A D. M. E (1993) Preservation of phenotype and function of positively selected virus-specific CD8+ T lymphocytes following anti-Fab detachment from immunomagnetic beads J Immunol Methods 161, 129-133... 

Escherichia coli Detection by immunoassay with immunomagnetic bead [117]... 

S.I. Tu, J. Uknalis and A. Gehring, Detection of immunomagnetic bead captured E. coli 0157 H7 by light addressable potentiometric sensor, J. Rapid Methods Autom. Microbiol., 7(2) (1999) 69-79. 

Immunomagnetic separation using immunomagnetic beads coated with sheep antimouse IgC ... 

Immunomz etic separation using uncoated immunomagnetic beads and... 

Immunomagnetic Beads Dynabeads uncoated, or coated as M-280 or M-450 sheep antimouse IgG (available from Dynal, Wirral, Merseyside, UK). Stored at 2-8°C, they will remain stable for up to 1 yr. Thiomerosal... 

Immunomagnetic beads can be obtained from Dynal, UK with sheep andmouse IgG attached (Secdon 3.1.1.) or uncoated for physical absorpdon of IgM andbodies or chemical coupling of IgG andbodies (as recommended by the producers) (Section 3.1.2.). 

For immunomagnetic beads with sheep antimouse IgG attached, the following protocol should be used to remove preservatives, such as thiomerosal or sodium azide, that may affect cell viability. 

Uncoated immunomagnetic beads can be coated with IgM usng the following procedure (13). Note that Metachem Diagnostics supply immunomagnetic particles with antimouse IgM attached. 

Remove the supernatant from uncoated immunomagnetic beads using the magnet for two minutes and either pouring or pipeting off the supernatant. 

The general consensus is that ideal conditions for separadon using immunomagnetic beads vary from system to system and must, therefore, be investigated by the individual using the technique. However, there are a number of useful points that should be considered. 

Cryptosporidium oocysts were selectively extracted (antibodies coupled to magnetic beads) from water concentrates using IMS. These oocysts were subsequently visualized using FITC conjugated monoclonal antibodies. However, dissociation from the immunomagnetic beads before labelling proved to be necessary (de Roubin et al. 2(X)2 Reynolds et al. 1999 Rushton et al. 2000). 

CA Wijayawardhana, G Wittstock, HB Halsall, WR Heineman. Electrochemical immunoassay with microscopic immunomagnetic bead domains and scanning electrochemical microscopy. Electroanalysis 12 640-644, 2000. 

---