Andrew V. Muchmore

Diminished lymphoblast 5'-nucleotidase activity in acute lymphoblastic leukemia with T-cell characteristics.

SINCE leukemic cells express certain cell-surface markers common to normal human lymphocytes, acute lymphoblastic leukemia can be differentiated immunologically into T-cell, B-cell and null (non-T,...

DEFECTIVE MONOCYTE KILLING IN PATIENTS WITH MALIGNANCIES AND RESTORATION OF FUNCTION DURING CHEMOTHERAPY

Spontaneous monocyte-mediated cytotoxicity (SMMC) in 34 patients treated with a chemotherapeutic regimen including cisplatin for various malignancies was depressed (median 7% 51Cr release) compared with SMMC in 31 normal controls (median 43%; p < 0.0001). Cytotoxicity in 7 patients with stage III or IV ovarian carcinoma was then followed during six cycles of chemotherapy with a cisplatin-containing regimen. All patients had initial cytotoxic values of < 8%, and in all SMMC increased at least three-fold between the third and fifth cycle of chemotherapy. This study lends support to the concept that cancer patients have depressed monocyte function. Cisplatin-containing chemotherapy seems to enhance monocyte function in vitro and in vivo.

A reappraisal of the effector cells mediating mitogen induced cellular cytotoxicity

Abstract The ability of mitogens to induce cytotoxic effector reactions in vitro has been studied to investigate basic mechanisms of cell mediated cytotoxicity. The type of mitogen, the source of effector cells, and the nature of the target cell are all critical variables in determining the characteristics of the cytotoxic event in this system. Spleen cells and bone marrow cells from congenitally athymic nude mice as well as from their heterozygous control littermates were capable of mediating lysis of RBC targets in the presence of either PHA or Con A. Removal of macrophages from these effector populations by adherence columns, density gradient centrifugation, and carrageenan treatment failed to abrogate this cytotoxic capacity. However, purified macrophages themselves also were capable of mediating mitogen induced killing of RBC targets, although the kinetics of this cytotoxicity were substantially different from that induced by lymphocytes. In contrast to these observations, the capacity of mitogen stimulated cells to kill metabolically active complex targets like the P815 mastocytoma or cultured L cells appears to be exclusively a T lymphocyte dependent function. In addition, blastogenic transformation of the effector cells with the T cell mitogens PHA and Con A, but not with the B cell mitogen LPS, leads to enhanced killing of these complex targets. These data suggest that mitogen or lectin induced cellular cytotoxicity can detect at least three different active effector cell types (B cells, T cells, and macrophages) acting via at least four different mechanisms.

Familial Chronic Lymphocytic Leukemia: Immunologic and Cellular Characterization

Chronic lymphocytic leukemia developed in four of five siblings, whose father succumbed to the same disease. The pattern of immune deficiency in the leukemic siblings resembled that found in nonfamilial cases of chronic lymphocytic leukemia, and was correlated with the severity of clinical involvement. In three siblings the peripheral blood leukemic cells shared delta-heavy and kappa-light chains as the only detectable surface immunoglobulin, suggesting that on a cellular and molecular level the chronic lymphocytic leukemia in family members is identical. The fourth and youngest sibling had no peripheral blood lymphocytes with detectable surface immunoglobulin. An inherited defect in the class of cells destined to express delta-heavy and kappa-light chains appears to underlie susceptibility to leukemia in this family.

Pregnancy-associated changes in oligomannose oligosaccharides of human and bovine uromodulin (Tamm-Horsfall glycoprotein)

The urinary glycoprotein uromodulin (Tamm-Horsfall glycoprotein) exhibits a pregnancy-associated ability to inhibit antigen-specific T cell proliferation, and the activity is associated with a carbohydrate moiety [Muchmore and Decker (1985) Science 229:479–81; Hessionet al., (1987) Science 237:1479–84; Muchmore, Shifrin and Decker (1987) J Immunol 138:2547–53]. We report here that the Man6(7)GlcNAc2-R glycopeptides derived from uromodulin inhibit antigen-specific T cell proliferation by 50% at 0.2–2 μM, and further studies, reported elsewhere, confirm that oligomannose glycopeptides from other sources are also inhibitory, with Man9GlcNAc2-R the most inhibitory of those tested [Muchmoreet al., J Leukocyte Biol (in press)]. In this work, we have extended the observation of pregnancy-associated inhibitory activity to a second species, and have compared the oligomannose profile of Tamm-Horsfall glycoprotein (nonpregnant) with that of uromodulin (pregnant) derived from both human and bovine sources. Surprisingly, there was a pregnancy-associated decrease in the total content of oligomannose chains due predominantly to a reduction in Man5GlcNAc2-R and Man6GlcNAc2-R. Man7GlcNAc2-R, which did not decrease with pregnancy, comprised a significantly greater proportion of the total oligomannose chains in pregnant vs. nonpregnant samples from both species (human; 34.6% vs. 25.9%: bovine; 14.4% vs. 7.2%).

In vitro cell aggregation and cell adhesion molecules in Crohn's disease

BACKGROUND Lack of a suitable model has hindered efforts to understand inflammation and granuloma formation in Crohns disease. METHODS Granulomalike aggregates of circulating mononuclear cells are produced in vitro by cultures of cells with polyacrylamide beads. To identify features of in vitro aggregates, which are similar to tissue granulomas of Crohns disease, the gross morphology and immunohistological appearance of the aggregates produced with peripheral blood mononuclear cells from patients with Crohns disease were analyzed, and the size of in vitro aggregates was correlated with clinical activity of the disease. Blocking antibodies were used to evaluate the role of cell-adhesion molecules in the formation of in vitro aggregates. RESULTS The size of in vitro aggregates correlates very significantly with clinical activity (P < 0.001). In active Crohns disease, in vitro aggregates show immunohistological features of hypersensitivity type granulomas. Blocking antibodies against leukocyte function associated antigen LFA-2 (CD2), LFA-3 (CD58), and Mac-1 (CD11b/CD18) inhibit in vitro aggregate formation. CONCLUSION In vitro aggregates model in vivo granulomas in size and organization. Cell adhesion molecules like CD2, CD58, and CD11b/CD18 may be involved in granuloma-formation of Crohns disease.

Induction of cytotoxic effector activity in the HL-60 promyelocytic cell line by incubation with phorbol myristate acetate: a model system of human spontaneous monocyte-mediated cytotoxicity.

In an attempt to develop a constant and reproducible in vitro system for a detailed analysis of cytotoxic effector mechanisms of nonimmune mononuclear phagocytes, the HL-60 promyelocytic cell line was studied for its cytotoxic action on chicken erythrocyte target cells. HL-60 cells cultured in complete medium were found to be noncytotoxic for chicken erythrocytes in an 18-hr 51Cr-release assay. These cells have been shown to acquire several characteristics of mature macrophages upon incubation with phorbol myristate acetate (PMA), and when PMA was included in the medium during the assay, the HL-60 cells became strongly cytotoxic to the target cells in the absence of exogenous antibody, lectin, or serum complement. Freshly isolated peripheral blood monocytes also became cytotoxic in the presence of PMA, whereas peripheral blood lymphocytes and the U937 histiocytic cell line did not. Detectable target lysis was observed between 4 and 8 hr after HL-60 stimulation with PMA, and HL-60 cells prestimulated with PMA for 24 hr retained their cytotoxic activity following washing and assay in PMA-free medium. Cytotoxic HL-60 cells developed after exposure to 10(-6) to 10(-9) M PMA, and significant target cell lysis occurred at effector:target cell ratios as low as 0.5:1. The PMA-induced HL-60-mediated cytotoxic response was markedly inhibited by blockers of protein synthesis, inhibition of microfilament function, and depletion of cellular superoxide and hydrogen peroxide. Interestingly, cytotoxicity of HL-60 cells for chicken erythrocyte targets was modulated by the direct addition of certain simple saccharides to the assay in a fashion similar to that observed with spontaneously cytotoxic mononuclear cells from several vertebrate and invertebrate species. Thus, the cytolytic effector function induced in HL-60 cells by incubation with PMA presents a useful model for the study of cellular cytotoxic mechanisms as well as the mechanisms utilized by nonimmune cells in the recognition of non-self.

Infectious Agammaglobulinemia: Suppressor T Cells with Specificity for Individual Immunoglobulin Classes

Immunoregulatory cells with potent suppressive effects on immunoglobulin or specific antibody production have been described in many experimental systems. In the chicken, bone marrow cells from adult birds rendered agammaglobulinemic by bursectomy and irradiation at hatching will induce agammaglobulinemia in recipients when transplanted into normal adult chickens of the same strain (1). This “infectious agammaglobulinemia” is induced by donor suppressor T cells which appear in the donor birds in detectable quantities by about 10 weeks of age. Suppressor cells can be demonstrated in spleen, thymus and peripheral blood in addition to bone marrow. The immunodeficiency which develops in the recipient chickens is characterized by their failure to produce specific antibody after challenge with any of several thymic dependent or thymic independent antigens, the rapid disappearance of existing serum IgG, IgA and IgM, the persistence of an intact bursa of Fabricius, and the persistence of a normal number of B lymphocytes in the spleen of these birds at least until after serum immunoglobulin has become undetectable (2, 3, 4).

Lymphokine and phorbol (PMA) regulation of complement (C2) synthesis using U937

Human monocytes synthesize large amounts of the second complement component (C2) after incubation with a T-lymphocyte product called monocyte complement stimulator (MCS). The human monocyte-like cell line, U937, also synthesizes C2 and can be stimulated to increase this synthesis by lymphokine-rich culture supernates. Additionally, phorbol myristate acetate (PMA), an agent which induces maturational changes in other macrophage-like cell lines, also stimulates C2 synthesis by U937 cells. Lymphokine and PMA stimulation of C2 secretion by U937 are both reversibly inhibitable by cycloheximide. At optimal concentrations for stimulation of C2 synthesis, PMA inhibits [3H]thymidine incorporation by U937 indicating that increased C2 is not due to increased numbers of U937 cells.

Uromodulin: a specific inhibitor of IL-1-initiated human T cell colony formation

Uromodulin, an 85 kDa naturally occurring immunosuppressant, was found to selectively and specifically inhibit the ability of IL-1 to induce colony responses by highly enriched suspensions of PHA-stimulated T lymphocytes. Dilutions of 1 x 10(-8) M completely blocked the colony growth of T lymphocytes cultured with 50 U/ml IL-1; 1 x 10(-9) M dilutions reduced scores by 83%. By contrast, uromodulin did not inhibit the responses of unseparated mononuclear cells, isolated T lymphocytes cultured with irradiated adherent cells, or stimulated T cells whose growth was initiated by either IL-2 or a soluble factor derived from Raji cells.