Use of anti-embryonic epsilon hemoglobin antibodies to identify fetal cells

#This invention relates to a method for separating and recognizing fetal cells from a blood sample. More particularly, it relates to the isolation and recognition of fetal nucleated erythrocytes or erythroblasts from maternal cells in a blood sample from a pregnant woman.

#Fetal tissue, and in particular fetal DNA and chromosomes, is routinely used in prenatal diagnosis and other medical procedures that require an accurate assessment of the genome of the fetus. Currently, the fetal tissue is obtained by the use of amniocentesis, chorionic villus sampling (CVS), fetoscopy, or cordocentesis, as described in Thompson and Thompson Genetics in Medicine, 5th Edition, W. B. Saunders Co., Philadelphia, 1991.

#In amniocentesis, a sample of amniotic fluid, which contains fetal cells, is transabdominally removed from the mother with a needle and syringe. Amniocentesis has inherent associated risks. The major risk is induction of miscarriage which is estimated to occur in 1 in 200 amniocenteses. Other risks include maternal infection and physical damage to the fetus. In CVS, trophoblast tissue is aspirated from the villous area of the chorion transcervically or transabdominally. The rate of fetal loss by this method may be as high as 1 in 100. Cordocentesis or percutaneous umbilical blood sampling provides a method of obtaining fetal blood directly from the umbilical cord with ultrasonic guidance. Each of these invasive methods carries risks to both the mother and the fetus.

#The following example is provided merely for the purposes of illustration and are not to be construed in any way as limiting the scope of the present invention. Those skilled in the art will recognize that certain variations and modifications can be practiced within the scope of the invention.

#Wedge smears were prepared from 14-week gestation abortus cord blood, whole blood from the mother (post-abortion), and a 1:25 mixture of the above cord blood into the maternal blood sample. The smears were fan dried for about half hour at room temperature, fixed in 100% methanol at -20.degree. C. for 10 minutes, and then in 100% acetone for 10 minutes at -20.degree. C.

#The slides were then washed in PBS (10 mM Phosphate Buffered Saline (pH 7.4) for 5 minutes at room temperature with moderate agitation and fixed in 2% formaldehyde/PBS at room temperature for 10 minutes with moderate agitation. After washing the slides twice in PBS for 5 minutes at room temperature with moderate agitation, the slides were washed twice in TBS (100 mM Tris-HCl pH 7.6) for 5 minutes at room temperature with moderate agitation.