Identification of a human protein homologous to the mouse Lyb-2 B cell differentiation antigen and sequence of the corresponding cDNA.
We have isolated and sequenced cDNA clones encoding the human homolog of the mouse Lyb-2 B cell differentiation Ag. Previous data suggest that Lyb-2 might represent a growth factor or lymphokine receptor. Human Lyb-2 mRNA is expressed in normal human tonsils and bone marrow cells, in the pre-B cell line REH, in three Burkitt lymphoma cell lines, and in some EBV-transformed B cell lines, but not in antibody-secreting myeloma cell lines, T cell lines, or a promyelocytic leukemia cell line. These data indicate that expression of human Lyb-2 is restricted to B lineage cells and turned off in antibody-secreting plasma cells. A polyclonal mouse antiserum was raised against human Lyb-2 and immunoprecipitates a Mr 42,000 protein from REH, Raji, and Daudi cells and from mouse L(tk) cells transfected with the human Lyb-2 cDNA in an expression vector. The human Lyb-2 protein is related to both the asialoglycoprotein receptor and CD23, the B cell-specific FcR for IgE. These data demonstrate that human B cells express a previously undescribed cell surface protein that is homologous to mouse Lyb-2 and has a similar pattern of expression during B cell development.
Von Hoegen
I
I
Department of Medicine, Stanford University Medical Center, CA 94305.
Nakayama
E
E
Parnes
J R
JR
D000595:Amino Acid Sequence; D000944:Antigens, Differentiation, B-Lymphocyte / Q000235:genetics*; D000950:Antigens, Ly / Q000235:genetics*; D037263:Asialoglycoprotein Receptor; D001402:B-Lymphocytes / Q000502:physiology*; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005796:Genes; D006801:Humans; D008969:Molecular Sequence Data; D011961:Receptors, Fc / Q000235:genetics; D017455:Receptors, IgE; D011971:Receptors, Immunologic / Q000235:genetics; D014162:Transfection
D000944:Antigens, Differentiation, B-Lymphocyte; D000950:Antigens, Ly; D037263:Asialoglycoprotein Receptor; D011961:Receptors, Fc; D017455:Receptors, IgE; D011971:Receptors, Immunologic; D004247:DNA