Summary and Highlights of Recover High Secretors or Rare Cells

A Symposium on Gel Microdrop Technology for Rapid Cell Line Enrichment

The Symposium, Recover High Secretors or Rare Cells, took place November 12 & 13^th at the Cambridge Marriott Hotel and at One Cell Systems’ Laboratory & Flow Cytometry Center. Dr. James Weaver, a Senior Researcher, Harvard-MIT Division of Health Sciences and Technology, and the inventor of Gel Microdrop Technology presented the opening seminar. Dr. Weaver detailed the development, background and utility of Gel Microdrops, Cell Encapsulation and Secretion Assays. Data was presented showing the isolation of cells present in a population at frequencies of 0.1% with a two to five-fold increase in protein production.

The four invited speakers shared their experiences with GMD Assays and detailed their experimental success. Greg Thill, Ph.D., a Senior Scientist at Biogen Corporation, gave an exact picture of how he and his colleagues optimized the GMD Secretion Assay for screening transfected cells in his seminar, "My Year with the GMD Secretion Assay." Dr. Thill described proof of principle experiments where in artificial and real life situations the efficacy of the Secretion Assay was demonstrated. The second part of his talk explained the optimization of parameters Dr. Thill and colleagues found to be necessary for the proper application of the Secretion Assay in their studies.

Jerry Carson, Senior Scientist, BASF Bioresearch Corporation, furthered the attendees knowledge and understanding of Secretion Assays in his lecture, "GMD Assay for Selecting Cell Lines and Monitoring Expression." Mr. Carson illustrated how the GMD Secretion Assay is used to screen large numbers of cells for their level of antibody expression. He and his associates have applied the technique to the development of cell lines for human antibody production. Mr. Carson described the use of GMDs in selecting lines of high expression level and how the assay has also been used to monitor the stability of protein expression in large scale bioreactors. Experiments identifying a low productivity subpopulation arising during fermentation were described.

Laura Chiu, Research Associate, Amgen Corporation, described a unique variation of the GMD Secretion Assay in "Isolation of High Protein Secretors from Cells Transfected with Fc Fusion Protein." Ms. Chiu explained the combination of a novel protein with the Fc portion of human IgG resulting in a secreted fusion protein. This fusion protein was then used as an analysis and purification tool for capturing membrane bound or soluble ligands and receptors. Ms. Chiu presented data relative to the development of a generic secretion assay that utilizes the Fc portion of the fusion protein. In the Amgen study, cells were transfected with a vector encoding the Fc fusion of interest, encapsulated, allowed to secrete and then sorted on the basis of high fluorescence. The targeted cells were then grown and assayed for protein production.

 Todd Parker, Research Biologist, Centers for Disease Control and Prevention, shared how he and his fellow scientists at CDC have exploited GMD Technology for diagnosis of emerging infectious diseases. Mr. Parker presented data supporting applications including co-culture models to investigate bacterial and mycotic virulence factors; isolation of hybridoma isotype switch mutants and the use of GMDs to normalize "cell" size for flow cytometric analysis of "clumped" cells. The experiments revealed how GMDs provided an optimal semi-permeable barrier that facilitated the study of microbial pathogenesis via cell attachment versus soluble factors. Mr. Parker presented data from studies of soluble mycotic virulence factors on a per cell basis either in the presence or absence of mycocidal drugs. Mr. Parker also detailed how GMDs were used to help facilitate flow cytometric analysis of microbes that have a strong tendency to clump. This clumping creates an obstacle in flow analysis in that the clumps can be made of 10 to 1000 individual cells. Utilizing GMDs, CDC Scientists were able to normalize "cell size" and analyze the population via flow cytometry.

Day 2 of the Conference featured an open Users Meeting with discussions led by Dr. Paul Durda, Director of Research and Development, and Claudia Cabral, Manager of Flow Cytometry at One Cell Systems. Dr. Durda shared suggestions and advice for secretion assay optimization and Ms. Cabral discussed special considerations and approaches for effective flow cytometric analysis and sorting of the GMD Secretion Assay. Many pertinent questions were asked and both One Cell Systems Scientists and current users of GMD Assays shared their knowledge and experience in answering the questions.

The attendees then transferred to One Cell Systems Worldwide Headquarters where they participated in a three part demonstration of GMD Assay Systems including cell encapsulation and microscopy, secretion assays and flow cytometry.

 

 Would you like more information about GMD Assays? E-Mail us at inforequest@onecell.com ; telephone us at (617) 868-2399, extension 309; or fax us at (617) 492-7921. Be sure to check our website regularly for details about other One Cell Systems Symposiums and Demonstrations.