Expression of the human monocyte membrane antigen gp55 by murine
fibroblasts after DNA-mediated gene transfer
RA Ashmun, SC Peiper, MB Rebentisch and AT Look
Human DNA sequences that contain the gene encoding gp55, a cell surface
glycoprotein expressed exclusively on mature human monocytes and monocytic
leukemia cells, were isolated in a mouse genetic background. DNA from
mature human monocytes was cotransfected with DNA from a molecularly cloned
feline sarcoma virus containing the v-fms oncogene into NIH-3T3 cells.
Transformed mouse fibroblasts that expressed gp55, based on their
reactivity with the MY4, B44.1, or LeuM3 monoclonal antibodies, were
selected by fluorescence-activated cell sorting. Regardless of which
antibody was used for selection, equivalent binding of all three antibodies
was observed for positive transformants. Secondary and tertiary mouse cell
transformants were obtained after additional rounds of transfection and
cell sorting with the use of DNA from primary and then secondary
transformants. Southern blot analysis of the cellular DNA from two
independently derived tertiary subclones revealed a limited complement of
human sequences, thus indicating that the gene encoding gp55 is included in
fewer than 50 kilobases of human DNA. Independently derived tertiary
subclones displayed concordant patterns of reactivity with 13
monocyte-specific monoclonal antibodies, thus indicating that each
recognized an epitope on the product (gp55) of a single human gene. The
55-kilodalton cell surface polypeptide was specifically immunoprecipitated
with a representative monoclonal antibody, 26if, from lysates of
enzymatically radioiodinated peripheral blood monocytes and tertiary
transformants. We conclude that gp55 is highly immunogenic and that a large
number of independently derived monoclonal antibodies specific for human
monocytes react with epitopes on this one molecule.
Volume 69,
Issue 3,
pp. 886-892,
03/01/1987
Copyright © 1987 by The American Society of Hematology
