Edwin S. Lennox

Monoclonal antibodies as probes for differentiation and tumor-associated antigens: a Forssman specificity on teratocarcinoma stem cells

A set of monoclonal antibodies derived by fusing P3-NS1/1-Ag4-1 myeloma cells with spleen cells from a rat immunized with mouse spleen were screened for activity against a tumor cell panel. One of these antibodies was found to react only with mouse embryonal carcinoma cells and no other tumor cell type tested, including differentiated derivatives of teratocarcinomas. In the adult mouse, this antigen is expressed by subpopulations of cells in the spleen, bone marrow, lymph node, brain, kidney and testes, although not in liver and thymus. This antigen has a species and tissue distribution consistent with that of Forssman antigen. The molecules which carry this specificity on the embryonal carcinoma cells appear to be glycolipids.

Monoclonal Anti‐A from a Hybrid‐Myeloma: Evaluation as a Blood Grouping Reagent

A monoclonal anti‐A antibody has been evaluated and found suitable for use as a potent routine ABO grouping reagent, without the use of additives. The IgM anti‐A (MH2/6D4) is secreted into the tissue culture supernatant by a permanent line of cloned cells derived by fusion of anti‐A producing spleen cells and a mouse myeloma cell line. This is a costeffective reagent which should reduce production costs by over 50%. This reagent has the advantages inherent in monoclonal antibodies among them the availability of unlimited quantities of unvarying antibody of known properties.

Monoclonal Anti‐B as a New Blood‐Typing Reagent

Abstract. Stable cloned lines of anti‐B‐secreting cells have been derived by fusing spleen cells of a mouse immunized by group B antigen with a mouse myeloma line. The tissue culture supernatant of one of them (NBI/19.112.28) containing secreted monoclonal anti‐B antibody is an especially good blood‐grouping reagent, well suited for use with manual and automated methods. The unlimited availability of a potent reagent of uniform properties, cheaply produced by a single source, makes monoclonal anti‐B a serious competitor to human typing serum.

A human-human monoclonal anti-D by direct fusion with a lymphoblastoid line.

Abstract. The human lymphoblastoid cell line W1‐L2–729‐HF2 has been fused with B cells from a plasmaphoresed anti‐D donor immunized with D+ cells. A stable monoclonal antibody‐producing cell line has been produced which yields culture supernatant of good titre without the need for concentration. The production and use of this reagent as an alternative Rh D typing reagent for use by saline and enzyme manual tests and automated tests in a Technicon 16C machine is discussed. Du red cells are detected in enzyme enhanced tests.

A new monoclonal anti-A. Culture supernatants with the performance of hyperimmune human reagents.

By proper selection for good growth and high avidity, we have prepared a new anti‐A monoclonal antibody producing cell line that gives culture supernatants as potent as US‐licensed commercial hyperimmune human reagents and which meet USA FDA standards without the need for concentration. The production and use of this reagent is cost effective and makes it a candidate to replace conventional anti‐A typing reagents.

The control of transferrin receptor synthesis in mitogen-stimulated human lymphocytes☆

Human lymphocytes cultured in the presence of the plant mitogenic lectin phytohemagglutin in (PHA) become activated and leave the G0 phase of the cell cycle. In the presence of PHA and lymphokines produced in situ the cells will enter S phase and undergo cell division. We have determined the time course of appearance for the receptor for transferrin as an initial attempt to understand the molecular mechanisms regulating the onset of lymphocyte differentiation and proliferation in the 48 h following PHA addition. Using three different assay methods we have shown that the increase in the number of surface receptor molecules is due to the accumulation of newly synthesized receptor and not to the redistribution of a previously existing pool of receptor molecules. The total amount of transferrin receptor increased at least four-fold. In vitro translation of RNA from activated lymphocytes indicates that the new receptor synthesis is due, at least in part, to increased availability of mRNA encoding the transferrin receptor.

The selection of monoclonal antibodies for tumour localization in patients with colorectal carcinoma.

We have investigated the ability of various predictive studies to assess which monoclonal antibody (MCA) will be most useful in the immunoscintigraphic localization of metastatic colorectal carcinoma. A set of MCAs was obtained by fusing splenic lymphocytes from rats immunized with membrane preparations from fresh human colorectal cancer. Supernatants from 17 cloned hybridomas were found to bind strongly to colon carcinoma lines by indirect radioimmunoassay. Immunofluorescence using these MCAs on sections of fresh frozen colon carcinoma and normal tissue revealed different staining patterns. Nine MCAs were purified and labelled with131I. Groups of mice bearing human colorectal tumour xenografts were given radiolabelled MCA and scanned. Six out of the nine MCAs showed tumour localization as determined by rectilinear scanning. Three MCAs which gave good tumour images in mice were selected for clinical evaluation in patients with advanced colorectal cancer. One gave good tumour images, another targeted to bone marrow and the third bound almost exclusively to normal liver. Clinical evaluation is clearly essential in the selection of MCAs for tumour localization.

Monoclonal Anti-A and Anti-B on Groupamatic

Abstract. Monoclonal anti‐A and Anti‐B from mouse‐mouse hybrid‐myeloma cell lines were tested in automated grouping on Groupamatic 360 C. Both sera were found to be suitable for Groupamatic typing. The anti‐B reagent was particularly potent, and could be used in a high dilution.