Ronald Billing

ENHANCEMENT OF HUMAN KIDNEY ALLOGRAFTS BY COLD B-LYMPHOCYTE CYTOTOXINS

The sera of 233 kidney transplant patients before transplantation were tested by cytotoxicity against a panel of B and T lymphocytes at 5 degrees C and 37 degrees C. The results divided the patients into four groups: those whose sera reacted with B lymphocytes at 5 degrees C; those reacting with B lymphocytes at 5 degrees C and 37 degrees C; those reacting with T lymphocytes at 37 degrees C; and those with no antibodies. The patients with pre-transplant antibodies reactive with B lymphocytes at 5 degrees C had a significantly higher kidney-transplant survival rate at 6 months (70%) and 1 year (65%) than patients who had no antibodies (47% and 46%, respectively). Patients with antibodies reactive at 37 degrees C had a 6-month survival-rate of 38% when reactive against B cells and 43% when reactive against T lymphocytes. The cold cytotoxins were IgM.

REVERSAL OF TRANSPLANT REJECTION BY MONOCLONAL ANTIBLAST ANTIBODY

The first clinical trial of an antiblast monoclonal antibody, CBL1, in the treatment of kidney allograft rejection is described. The theory that this antibody might destroy active clones of cells without major side effects was given validity by a previously described study showing prolongation of skin allograft survival in rhesus monkeys. CBL1 was used to treat kidney allograft rejections in 11 patients with a one-haplotype-identical related-donor graft who had been prestimulated with donor-specific transfusions and 8 patients with cadaver grafts who had been prestimulated with multiple transfusions. 15 of the rejections were steroid-resistant. Although CBL1 had no effect on the peripheral blood lymphocyte counts, rejections were reversed in 17 of 19 patients. There was 1 graft loss in the 11 recipients of related-donor grafts and 3 in patients with cadaver-donor grafts. Side effects associated with administration of antilymphocyte serum--ie, chills, fever, and thrombocytopenia--did not develop in any of the patients treated with CBL1. It is postulated that administration of an antiblast monoclonal antibody during rejection of a kidney kills only those cells that are reacting against the graft. This could result in the maintenance of normal lymphocyte numbers and immunological functions against other antigens.

Acute Leukemia: Biology and Treatment

A fundamental abnormality in acute myeloid leukemia is a block in cell differentiation with resultant accumulation of immature leukocytes. This abnormality can be studied in continuously growing leukemic cell lines that differentiate with simple chemical signals. Surface antigenic modulation occurring with cell differentiation can be monitored by specific antisera. These antisera have great potential as diagnostic and therapeutic reagents. More than 90% of patients with acute lymphoblastic leukemia and more than 70% of patients with acute myeloid leukemia can achieve remission of disease with aggressive multiagent chemotherapy. Long-term, disease-free survival is obtainable in about one half of patients with acute lymphoblastic leukemia but in less than 15% of patients with acute myeloid leukemia. The future directions of research for achieving cure of acute leukemia seem to be well defined.

Crossreactivity between human and canine Ia antigens using a mouse monoclonal antibody (CIA).

A mouse monoclonal antibody (CIA) produced against human Ia antigens that reacts with 20–30% of human peripheral blood lymphocytes was found to react with more than 90% of dog lymphocytes. Less than 41% of the la-positive dog lymphocytes expressed surface immunoglobulins. Immunoprecipitation studies with 125I- labeled cells precipitated heavily labeled Ia bands at 28K and 35K from human cells, but from dog cells the 29K β chain of Ia was much more heavily labeled than the α chain.

CYTOTOXIC MONOCLONAL ANTIBODY TO A HUMAN LEIOMYOSARCOMA

A monoclonal antibody produced by the hybridoma technique against a human leiomyosarcoma was highly cytotoxic in dilutions of 1:64 000 to the original tumour cells. The antibody was unreactive with most normal cells (lymphocytes, 120 donors; spleen cells, 73/75; monocytes, 16; granulocytes, 25; platelets, 12; red cells, 11) and could not be absorbed out by smooth muscle from the small intestine or by spleen cells. Its specificity for the tumour was high since it did not react with cells from 40 patients with leukaemia, from 8 patients with other tumours, and from 7 cultured tumour lines. The only other cell that it reacted with (at 1:4000 dilution) was line 8402, a T acute lymphocytic leukaemia line. This monoclonal antibody may be suitable for therapeutic trials.

Acute myelogenous leukemia heteroantisera

Abstract Antisera were raised in New Zealand white rabbits to acute myelogenous leukemia (AML) cells. Reactivity of the antisera against normal T lymphocytes was eliminated by pretreating the rabbits with anti-leukocyte serum (ALS) and precoating the immunizing cell with ALS. Following absorption with acute lymphocytic leukemia (ALL) cells the antisera appeared to be specific for certain acute leukemia cells. By complement-dependent cytotoxicity testing leukemia cells from 10 46 AML and 2 23 ALL patients were positive. The cytotoxicity titers ranged from 1:8 to 1:32. The undiluted sera showed no reactivity with normal peripheral blood B or T lymphocytes, normal granulocytes, chronic myelocytic leukemia cells, or chronic lymphocytic leukemia cells. Two recently initiated AML cell lines (KG and ML3) were positive and a third AML line (HL60) was negative. Several other B- and T-cell lines were negative. Positive ALL cells were able to remove the cytotoxicity against positive AML cells suggesting a common antigen(s) was involved. The AML antigen was not expressed on myeloid stem cells (CFU-C) from normal human bone marrow.

Immunologic classification of childhood acute lymphocytic leukemia

Immunologic approaches to the classification of acute lymphocytic leukemia (ALL) have led to a new awareness of the heterogeneity of this disease. Surface membrane markers including surface membrane immunoglobulin, complement receptors, and sheep erythrocyte (E) receptors have demonstrated at least three subtypes of ALL, which include non‐B, non‐T ALL, T‐ALL, and B‐ALL. In addition, hetero‐antisera to Ia‐like antigens and ALL‐associated antigens have been used to positively identify non‐B, non‐T ALL, which was previously a diagnosis of exclusion. This paper reports 17 cases of childhood ALL whose lymphoblasts were studied for surface membrane immunoglobulin, sheep erythrocyte receptors, and the presence of four antigens detected by well‐characterized heteroantisera. Every non‐B, non‐T lymphoblast was positively identified by the la‐like antiserum and/or the ALL antiserum. One T lymphoblast was identified by E receptors and the T antiserum, whereas two did not have E receptors but did react to the T antiserum. None of these three T lymphoblasts reacted with the Ia‐like antiserum.

MONOCLONAL ANTIBODY SPECIFIC FOR HUMAN T ACUTE LYMPHOBLASTIC LEUKAEMIA

A cytotoxic mouse monoclonal antibody (CALL2) was produced against a cultured T acute lymphocytic leukaemia (T ALL) cell line 8402. Ascites fluid containing the antibody was cytotoxic to a titre of up to 1:100 000 against 4 of 6 cultured T ALL cell lines and against leukaemia cells from 7 of 8 T ALL patients and 1 of 5 T chronic lymphatic leukaemia patients. The antibody did not react with normal peripheral-blood T and B lymphocytes, monocytes, granulocytes, spleen cells, thymocytes, platelets, and other acute and chronic leukaemia cells. The CALL2 antibody did not react with bone marrow stem cells of the myeloid series (CFU-C). This antibody may be useful for passive immunotherapy trials since it does not react with normal cells and is highly cytotoxic to T ALL cells.

Expression of Ia-like antigens on human erythroid progenitor cells as determined by monoclonal antibodies and heteroantiserum to Ia-like antigens☆☆☆

Abstract Based on studies using anti-Ia-like heteroantisera, it has been concluded that human erythroid progenitor cells (CFU-E and BFU-E) express Ia-like antigens. We attempted to confirm these findings using a well-characterized anti-Ia-like heteroantiserum and hybridoma-derived monoclonal antibodies against Ia-like antigens. Specificity of the monoclonal antibodies was demonstrated by the pattern of reactivity against a panel of Ia-positive and Ia-negative cells and by immunochemical techniques. Normal human bone marrow or peripheral blood buffy coat cells were incubated with anti-Ia-like heteroantiserum or monoclonal antibody, with and without complement, washed, and plated with the appropriate humoral stimulator in semisolid media for determination of CFU-C, BFU-E, and CFU-E. Anti-Ia-like heteroantiserum produced complement-dependent inhibition of CFU-C-, BFU-E, and CFU-E-derived colony formation. Monoclonal anti-Ia-like antibody caused complement-dependent inhibition of CFU-C that persisted to a titer of 1:1000, but did not inhibit colony formation by BFU-E and CFU-E. Our results suggest either that erythroid progenitor cells do not express Ia-like antigens or that these antigens, if present, are expressed at very low density or in altered configuration, thus rendering them apparently unreactive with our monoclonal antibodies in a cytotoxicity assay.

Detection of differentiation antigens by use of monoclonal antibodies

Various monoclonal antisera placed at appropriate dilutions in a microcytotoxicity typing tray can be used to characterize different cell types with the aid of a simple 2-h microcytotoxicity test. With this simple assay, T and B lymphocytes, granulocytes, monocytes, blast cells, and platelets can readily be distinguished. In addition, spleen cells contained 25-50% T cells, half of which expressed Ia antigens. The presence of Ia-bearing T cells in peripheral blood lymphocytes of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) patients can also be detected using this cytotoxicity tray.