Unlike Morris' older machine, which merely counted the labeled cells, the new one separates and sorts cells at the end of the analysis, so these purified batches can be analyzed further. In addition, it can simultaneously sort through more cell subcategories than the older one. Both models were purchased through grants from the Oakland-based Hedco Foundation, which supports the purchase of medical research equipment. Among other uses, flow cytometers can detect the effects of drugs on cells from treated animals and patients. Morris' team plans to use the equipment to optimize complex immunosuppressive drug-dosing regimens for people receiving organ transplants.
Lower levels lead to rejection, while higher levels result in infection.
In animal studies over the past two years, Morris' group has used flow cytometry to establish that the effects of new drugs on immune cells in the bloodstream correlate well with the drugs' ability to stave off tissue rejection. To do these studies, the researchers first stimulate blood cells from the graft recipient by a process that mimics exposure to a donor organ. Then, using new methods developed by the group, they use the flow cytometer to find out whether the cells rise to the challenge or the drug has successfully subdued them. Morris thinks the expanding flow cytometry facilities and capabilities are likely to interest other Stanford researchers, especially those seeking to trace which cells are involved in a disease or to learn how cells respond to anticancer agents or other drugs. With the older machine, he identified the blood cells that stick to the inner lining of blood vessels when cholesterol levels are elevated.