Abstract: This invention provides methods and compositions useful for identifying and diagnosing rare fetal cells in a mixed cell population such as a maternal blood sample. The methods entail the use of specific nucleic acid probes that hybridize to fetal cell associated RNAs to identify the rare fetal cells or antibodies that bind to polypeptides encoded by the fetal cell associated RNAs for fetal cell detection. The cells detected by the methods of the present invention are useful for diagnosing the fetal cells for a genetic trait of interest, such as trisomy 21. Novel methods for simultaneous screening for fetal cells and diagnosing the fetal cells are also provided. Compositions comprising the fetal cell associated nucleic acids of the invention and their encoded proteins are also provided. The present invention further provides kits useful for practicing the present methods.

Abstract: This invention provides methods and compositions useful for identifying and diagnosing rare fetal cells in a mixed cell population such as a maternal blood sample. The methods entail the use of specific nucleic acid probes that hybridize to fetal cell associated RNAs to identify the rare fetal cells or antibodies that bind to polypeptides encoded by the fetal cell associated RNAs for fetal cell detection. The cells detected by the methods of the present invention are useful for diagnosing the fetal cells for a genetic trait of interest, such as trisomy 21. Novel methods for simultaneous screening for fetal cells and diagnosing the fetal cells are also provided. Compositions comprising the fetal cell associated nucleic acids of the invention and their encoded proteins are also provided. The present invention further provides kits useful for practicing the present methods.

Abstract: Methods for isolating trophoblast cells from pregnant women are provided. A central maternal blood sample is obtained, typically from the uterine wall of a pregnant woman. The trophoblast cells are isolated from the central maternal blood sample.

Abstract: This invention provides a method for measuring an antigen concentration in a sample, which comprises: preparing VH-domain polypeptide and VL-domain polypeptide of an antibody specific to the antigen; labeling one of the polypeptides with a reporter molecule to form labeled polypeptides, and immobilizing the other polypeptide onto solid-phase to form immobilized polypeptides; contacting the antigen-containing sample and the labeled polypeptides with the solid-phase; and measuring the reporter molecule of the labeled polypeptides bound to the immobilized polypeptides. The present invention permits simpler and quicker sandwich ELISA for measurements of an antigen concentration in high sensitivity.

Abstract: Methods for isolating trophoblast cells from pregnant women are provided. A central maternal blood sample is obtained, typically from the uterine wall of a pregnant woman. The trophoblast cells are isolated from the central maternal blood sample.

Abstract: Improved methods for obtaining polynucleotides comprising sequences which differ between two populations of DNA or CDNA are provided. Improvements include reduction in the number of amplification cycles, use of a nuclease digestion step prior to amplification, a novel oligonucleotide adapter for the practice of the improved method, and novel methods for selective amplification of the desired unique fragments and selective degradation of fragments containing sequences common to both populations. Fragments of a sample population are amplified using a primer that endows the amplification products with resistance to nuclease degradation. Fragments of a control population are amplified using a primer that targets the amplification products for preferential degradation. Multiple cycles of hybridization, nuclease treatment and amplification are utilized to provide enrichment of fragments unique to the sample population.

Abstract: This invention provides a method for measuring an antigen concentration in a sample, which comprises: preparing VH-domain polypeptide and VL-domain polypeptide of an antibody specific to the antigen; labeling one of the polypeptides with a reporter molecule to form labeled polypeptides, and immobilizing the other polypeptides onto solid-phase to form immobilized polypeptides; contacting the antigen-containing sample and the labeled polypeptides with the solid-phase; and measuring the reporter molecule of the labeled polypeptides bound to the immobilized polypeptides. The present invention permits simpler and quicker sandwich ELISA for measurements of an antigen concentration in high sensitivity.

Abstract: Improved methods for obtaining polynucleotides comprising sequences which differ between two populations of DNA or cDNA are provided. Improvements include reduction in the number of amplification cycles, use of a nuclease digestion step prior to amplification, a novel oligonucleotide adapter for the practice of the improved method, and novel methods for selective amplification of the desired unique fragments and selective degradation of fragments containing sequences common to both populations. Fragments of a sample population are amplified using a primer that endows the amplification products with resistance to nuclease degradation. Fragments of a control population are amplified using a primer that targets the amplification products for preferential degradation. Multiple cycles of hybridization, nuclease treatment and amplification are utilized to provide enrichment of fragments unique to the sample population.