The use of various proteins to modify the human immune system response is of intense interest in the areas of organ transplants, AIDS, and chemotherapy. At the NCI, several new drugs have been developed for this purpose.. At present, these drugs are available only in small amounts (approximately 1 ml). By mixing these drugs with carefully constructed molecules ' of DNA and measuring the enthalpy, the drug-DNA bond interactions can be determined. Investigators at the NCI and NIDDK consulted BEIB and LTD in regards to tantalum stopped flow microcalorimeter which has the capability of measuring heats of 10 microjoules or less in 80 microliter samples. The first experiments showed that we could measure heats in the range of 5 microjoules with a standard error of less than 0.5 microjoules. Preliminary results show that the enthalpy is very low which indicates that the binding is almost exclusively entropy driven.
