The KOR-SA3544 antigen predominantly expressed on the surface of Philadelphia chromosome-positive acute lymphoblastic leukemia cells is nonspecific cross-reacting antigen-50/90 (CD66c) and invariably expressed in cytoplasm of human leukemia cells.
We previously reported a novel monoclonal antibody KOR-SA3544 which predominantly reacted with a surface antigen (sSA3544) expressed on Philadelphia chromosome (Ph1)-positive acute lymphoblastic leukemia (ALL). In the present study, we demonstrate that the antibody specifically recognized nonspecific cross-reacting antigen (NCA)-50/90 (CD66c), one of the carcinoembryonic antigen (CEA)-related glycoproteins encoded by a member of the CEA gene family. In addition, we show that the SA3544 antigen (NCA-50/90) was invariably expressed in cytoplasm of all of the human leukemic cell lines examined (sSA3544-positive B-lymphoid two, sSA3544-negative T or B-lymphoid and non-lymphoid 24) regardless of the presence or absence of surface expression of this antigen. Immunoelectromicroscopic examination revealed that the cytoplasmic antigen was mainly present in granules in sSA3544-positive leukemia cells, whereas it was diffusely present in cytosol in sSA3544-negative leukemia cells. Thus, among members of the CEA family, NCA-50/90 was first demonstrated to be expressed not only on the surface of some leukemia cells, but also in cytoplasm of various types of leukemia cells.
Sugita
K
K
Department of Pediatrics, Yamanashi Medical University, Japan.
Mori
T
T
Yokota
S
S
Kuroki
M
M
Koyama
T O
TO
Inukai
T
T
Iijima
K
K
Goi
K
K
Tezuka
T
T
Kojika
S
S
Shiraishi
K
K
Nakamura
M
M
Miyamoto
N
N
Karakida
N
N
Kagami
K
K
Nakazawa
S
S
D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD; D000951:Antigens, Neoplasm; D015153:Blotting, Western; D015815:Cell Adhesion Molecules; D003593:Cytoplasm / Q000737:chemistry*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D058851:GPI-Linked Proteins; D006098:Granulocytes / Q000737:chemistry; D006801:Humans; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000032:analysis*; D010677:Philadelphia Chromosome; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000276:immunology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000951:Antigens, Neoplasm; C504117:CEACAM6 protein, human; D015815:Cell Adhesion Molecules; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins