The epitope specificity and tissue reactivity of four murine monoclonal anti-CD22 antibodies.
The CD22 antigen is expressed on the surface of normal human B cells and some neoplastic B cell lines and tumors. Previous cross-blocking studies using a panel of monoclonal anti-CD22 antibodies have defined four epitope groups, termed A-D. In the present studies, we have further dissected the epitopes recognized by four monoclonal anti-CD22 antibodies using immunoprecipitation and cross-blocking techniques, immunofluorescence analyses with a variety of cell lines, and immunoperoxidase analyses of 36 normal human tissues. Two of the antibodies, HD6 and RFB4, have been described previously, and two, UV22-1 and UV22-2, are described in this report. Our studies indicate that the four monoclonal antibodies show unexpected complexities in their reactivity with CD22+ and CD22- cells and their reactivity with solubilized CD22 molecules. The four antibodies, which recognize epitopes defined previously as CD22-A and CD22-B, further subdivide these epitope clusters into four determinants, A1, A2, B1, and B2. Furthermore, only two of the antibodies, RFB4 and UV22-2, are B cell-specific. In summary, our data indicate that RFB4 and UV22-2 would be the antibodies of choice for constructing immunotoxins to treat B cell tumors.
Li
J L
JL
Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235.
Shen
G L
GL
Ghetie
M A
MA
May
R D
RD
Till
M
M
Ghetie
V
V
Uhr
J W
JW
Janossy
G
G
Thorpe
P E
PE
Amlot
P
P
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D002051:Burkitt Lymphoma / Q000473:pathology; D015815:Cell Adhesion Molecules; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D037102:Lectins; D008253:Macaca mulatta; D051379:Mice; D051918:Sialic Acid Binding Ig-like Lectin 2; D013045:Species Specificity; D014407:Tumor Cells, Cultured / Q000276:immunology
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D000951:Antigens, Neoplasm; C497867:CD22 protein, human; C497868:Cd22 protein, mouse; D015815:Cell Adhesion Molecules; D000939:Epitopes; D037102:Lectins; D051918:Sialic Acid Binding Ig-like Lectin 2