Rat AL2, AL3, AL4 and AL5 monoclonal antibodies bind to the common acute lymphoblastic leukaemia antigen (CALLA gp 100)

Abstract

Four distinct rat monoclonal antibodies against the common ALL antigen (CALLA, gp 100) were obtained in a single fusion. Rat AL2, AL3, AL4, AL5 and the previously reported mouse J5 monoclonal antibodies identified the same subsets of leukaemic cells. AL2 and AL3 reacted weakly with terminal transferase-positive cells in normal bone marrow and foetal liver, as well as with a minority of mature granulocytes in blood. Immunoprecipitation experiments and competitive binding assays demonstrated that the four rat antibodies and J5 bound to the same glycoprotein of approximately 100,000 mol. wt. This set of rat monoclonal antibodies directed against CALLA has not only a diagnostic usefulness but may also be of therapeutic value.

Common acute lymphocytic leukemia antigen is identical to neutral endopeptidase.

“…Within the kidney, where they are particularly abundant, both CALLA and NEP are found on the brush border of proximal tubules and on glomerular epithelium (9-11, 21-23, 31). CALLA antigens from leukemic cells (4)(5)(6)(7)(8)16), kidney (9,11), melanoma (17), glioma (18), granulocytes (14,15,19), or fibroblasts (15), and NEP from kidney (21)(22)(23)(28)(29), brain (28), or fibroblasts FIGURE 2 . Northern blot of human leukemic cells and fibroblasts probed with CALLA cDNA . RNA samples (20 pg) prepared from the HOON (H) and NALM-6 (N) pre-B ALL cell lines and from human (HF) or mouse (MF) fibroblasts were fractionated on a denaturing agarose gel.…”

“…CALLA was purified from kidney extracts by immunoaffinity chromatography using mAb 44C10, produced by immunisation with the CALLA-positive leukemic cell line HOON (8), and reactive with the same epitope as other widely used anti-CALLA mAb (2)(3)(4)(5)(6)(7)(8) . The M, of the antigens immunoprecipitated with mAb 44C10 were estimated at 9.4 x 104 (kidney) and 105 (NOON) ; after Endo F digestion, both polypeptides had an apparent M, of 8 x 104.…”

Childhood leukaemia and lymphoma: African experience supports a role for environmental factors in leukaemogenesis

“…The laboratory procedures of immunophenotypic characterization were performed according to the protocol of the International Study of Cell Markers in Leukaemias and Lymphomas as outlined by Greaves et al [ 16 ], using a panel of first generation reagents including: J 5 [ 17 ] and AL2 [ 18 ], both anti CALLA; DA 2, an anti HLA DR [ 19 ], WT 1, an anti T [ 20 ] and OKT11a, an anti E rosette receptor [ 21 ]; and My906, an anti myeloid [ 22 , 23 ] monoclonal antibody. A large number of heterologous anti sera, such as anti Ig, anti kappa, anti lambda, and anti Tdt (terminal deoxynucleotidyl transferase) were also included in the panel [ 24 ]; anti T subset murine monoclonal antibodies, including OKT3, OKT4, OKT6, and OKT8 [ 25 , 26 ].…”