Patent ID: 6893881

Claim:
A method for detecting a specific living target cell in a cell suspension of a mixed cell population, in a fluid system containing a mixed cell population, or in a cell suspension prepared from a solid tissue with the exception of normal and malignant hematopoietic cells in blood and bone marrow, the method comprising the steps of: a. coating paramagnetic particles or beads with a fist antibody or antibody fragment directed against a second antibody or antibody fragment; b. incubating the second antibody or antibody fragment with the cell suspension to bind the second antibody or antibody fragment with the target cell, thereby creating a cell mixture, wherein the second antibody or antibody fragment is directed against a membrane structure specifically expressed on the target cell and not on a non-target cell in the cell mixture; c. washing the cell mixture to remove unbound second antibody or antibody fragment; d. mixing the coated paramagnetic particles or beads with the washed cell mixture; e. incubating the washed cell mixture and the coated paramagnetic particles under gentle rotation at about 4° C. until target cell-bead rosettes are formed; and g. visually detecting the target cell-bead rosettes after incubation; wherein the target cells are living and can be detected at a sensitivity of one target cell per 100 or more total cells.