Purified human granulocyte-macrophage colony-stimulating factor: direct action on neutrophils.

Neutrophil migration inhibition factor from T lymphocytes (NIF-T) is a lymphokine that acts to localize granulocytes. Medium conditioned by the Mo human T-lymphoblast cell line was used to purify NIF-T, a glycoprotein with a molecular weight of 22,000. The NIF-T was found to potently stimulate the growth of granulocyte and macrophage colonies from human bone marrow and colony formation by the KG-1 myeloid leukemia cell line. Thus a human lymphokine (NIF-T) that modulates the activities of mature neutrophilic granulocytes is also a colony-stimulating factor acting on precursors to induce growth and differentiation of new effector cells.

Two kappa immunoglobulin light chains are secreted by an anti-DNA hybridoma: implications for isotypic exclusion.

An anti-DNA hybridoma derived from an MRL/lpr mouse secretes two different kappa light chains in combination with a single heavy chain. Multiple single cell clones express and secrete immunoglobulin containing both kappa light chains. The N-terminal protein sequences of the light chains correspond to sequences predicted from functionally rearranged mRNAs subjected to reverse transcription and amplified by polymerase chain reaction (PCR). Karyotype analysis of the hybridoma indicates a clonal line derived from the fusion of two cells. By amino acid sequence comparison and PCR analysis, both functional kappa light chains are derived from the MRL/lpr spleen. The two functional light chain cDNAs were cloned and co-transfected into COS-7 cells with the heavy chain cDNA. Only one of the light chains in combination with mAb 3E10 heavy chain confers anti-DNA reactivity. The presence of two separate kappa light chains and, therefore, two separate antigen receptors on a single B cell may have ramifications for both polyclonal activation and toleration of lupus B cells.

A microassay for leukocyte migration: analysis of its reproducibility.

A reliable microassay for human leukocyte migration is described by which 50 to 100 assays can be performed each day in quadruplicate with the number of indicator cells obtainable from 10 to 20 ml of peripheral blood. The reproducibility of this method is demonstrated with respect to the variability among replicate test wells (including reading), the variability among different test readers, the variability among replicate cultures, and the variability of using indicator cells from different subjects. A microculture system is described that requires only 75,000 mononuclear cells to consistently produce detectable polymorphonuclear leukocyte migration inhibition factor in response to PPD. The reproducibility of this culture system is demonstrated with respect to the variability of lymphocyte responsiveness on repetitive testing in the same individuals.

Physiology of granulocyte and macrophage colony-stimulating factors in host defense.

The colony-stimulating factors (CSF) are a family of glycoprotein hormones that regulate the proliferation and maturation of hematopoietic progenitor cells. In addition to their effects on hematopoiesis, CSFs modulate the function of fully mature cells and, therefore, play an important role in regulating inflammatory responses vital to host defense. Here we review recent information that describes the biological activity of the CSFs on mature cell function, including chemotaxis, adherence, motility, phagocytosis, oxidative metabolism, and cytotoxicity.

Apheresis enhances the selective removal of antinuclear antibodies in systemic lupus erythematosus.

Apheresis suppresses clinical manifestations of lupus and reduces levels of antinuclear antibodies implicated in the pathogenesis of systemic lupus erythematosus (SLE). It is not known, however, if reduced levels of antinuclear antibodies are due to nonspecific removal, or specific mechanisms associated with decreased production, or enhanced clearance from the circulation. In order to distinguish between specific and nonspecific effects of apheresis on antinuclear antibodies in SLE, we compared plasma levels of IgG antibodies to DNA and IgG antibodies to microbial antigens in 13 SLE patients before and after apheresis. Although apheresis lowered plasma levels of IgG (21% mean reduction), there was a disproportionate reduction in IgG antibodies to DNA (42% mean reduction, p less than 0.13). In marked contrast, reduction in antibodies to microbial antigens did not exceed those of plasma IgG. A rapid rebound of serum anti-DNA antibodies following apheresis in certain SLE patients suggests that the selective reduction in anti-DNA antibodies is due to enhanced clearance from the circulation rather than decreased production. These results indicate that apheresis enhances selective removal of antinuclear antibodies in some patients with SLE.

An antibody that binds a neutrophil membrane protein, ERp72, primes human neutrophils for enhanced oxidative metabolism in response to formyl-methionyl-leucyl-phenylalanine. Implications for ERp72 in the signal transduction pathway for neutrophil priming.

Human neutrophils are primed by cytokines for enhanced oxidative metabolism in response to chemotactic factors, but the signal transduction pathways for cytokine activation and priming are unknown. Neutrophil priming may play an important role in mechanisms of host defense and inflammatory responses associated with autoimmune diseases. A rabbit antibody was produced that reacted with human neutrophils and induced priming in response to the chemoattractant, FMLP. The protein responsible for neutrophil priming in response to binding antibody was identified in a neutrophil cDNA library by expression cloning. The cloned protein absorbed the neutrophil-priming activity from rabbit serum. Furthermore, antibody priming activity was recovered by elution from the cloned protein. The gene for the protein associated with neutrophil priming was sequenced and identified as the endoplasmic reticulum protein, ERp72, which contains three copies of the active site sequences of protein disulfide isomerase. The antibody that primed neutrophils was shown to bind ERp72 in neutrophil membranes by immunoprecipitation of the same 72-kDa protein from neutrophils as a known antibody to ERp72. These studies implicate ERp72 in the signal transduction pathway for priming human neutrophils.

Requirement for B-lymphocyte alloantigen in the production of neutrophil migration inhibition factor from T lymphocytes (NIF-T).

Neutrophil migration inhibition factor from T lymphocytes (NIF-T) is produced in response to mitogens as the result of cellular interactions between T and B lymphocytes. The requirement for B-cell alloantigen in this interaction process was indicated by (1) collaboration between peripheral blood T cells with various B lymphoblast cell lines but not with non-B lymphoblast cells for NIF-T production, (2) inhibition of NIF-T production by treating collaborating B lymphoblasts with B-cell specific antiserum, and (3) inhibition of NIF-T production by peripheral blood lypmphocytes in the presence of anti-B-cell antiserum and F(ab')2 with anti-B-cell specificity.

The fine specificity of IgG antiguanosine antibodies in systemic lupus erythematosus.

The antigen specificity, isotype, and subclass of antinuclear antibodies may be related to their pathogenicity in systemic lupus erythematosus (SLE). Our laboratory found that IgG antibodies that bound the nucleoside, guanosine, occurred frequently in SLE patients. In contrast, sera from healthy subjects contained IgM but not IgG antiguanosine antibodies. The present studies were designed to characterized the fine specificity of IgG antiguanosine antibodies in SLE and compare them with IgM antiguanosine antibodies in normal sera. Serum antinuclear antibodies from six healthy subjects and six SLE patients were isolated by affinity binding to guanosine and measured by an enzyme-linked immunosorbent assay (ELISA). IgM in normal sera, and both IgM and IgG in SLE sera bound guanosine. IgM antiguanosine antibodies in normal sera were polyspecific and bound other nucleosides and 1-methylguanosine but not denatured DNA (ssDNA). In contrast, IgG antiguanosine antibodies from the SLE patients bound guanosine and ssDNA but not other nucleosides or 1-methylguanosine. SLE IgM antiguanosine antibodies had the same fine specificity and bound guanosine and ssDNA but not any of the other nucleosides. These results suggest that SLE IgG and IgM antiguanosine antibodies have fine specificity in contrast to the polyspecific IgM antibodies in normal sera. In addition, subclass analysis indicated that all SLE patients had either IgG1 or IgG3 subclass of antiguanosine antibodies that bind complement. Characterizing the isotype, subclass, and fine antigen specificity of antiguanosine antibodies should assist in evaluating their potential pathogenicity in SLE.

Effect of corticosteroids on serum antinuclear antibodies in man.

The effect of prednisone on serum levels of IgG antibodies to viral and bacterial antigens was measured and compared to its effect on IgG antibodies to nuclear antigens in 8 patients with systemic lupus erythematosus. Prednisone at 15-80 mg/day (mean 55 mg/day) for 14-30 days (mean 19 days) lowered the serum IgG by an average of 22% (p less than 0.005). An even greater reduction in IgG antinuclear antibodies occurred (mean 43%, p less than 0.001) including responses to double stranded DNA, single stranded DNA, and the nucleosides, adenosine, guanosine, cytidine and thymine riboside. In contrast, there was no alteration in serum IgG antibody levels to influenza virus vaccine and pneumococcal vaccine antigens. These results suggest that prednisone has a selective effect on the expression of autoimmunity which may, in part, be responsible for its clinical efficacy in systemic lupus erythematosus.

Responses of neutrophils to myeloid growth factors.

Colony-stimulating factors (CSFs) have important effects on mature myeloid cells in addition to their regulatory role in haemopoiesis. Exposure of neutrophils to granulocyte macrophage-CSF (GM-CSF) increases chemotaxis, phagocytosis and cytotoxicity and primes the cells for enhanced oxidative metabolism in response to stimuli, such as formylated oligopeptides derived from bacteria (f-Met-Leu-Phe) and endogenous activated complement components (C5a). GM-CSF induces time-dependent changes in neutrophil f-Met-Leu-Phe receptor number and affinity that correspond to changes in functional activity. The neutrophil IgA Fc receptor is also modulated by GM-CSF such that it develops a high affinity state and transduces a phagocytic signal. The ability to regulate the number and activity of mature myeloid effector cells in vivo establishes unique therapeutic opportunities in the area of infectious disease, cancer treatment, bone marrow transplantation and augmentation of host defence in immunodeficient patients.

Novel structural features of autoantibodies in murine lupus: a possible superantigen binding site?

The stimulus for the production of anti-DNA autoantibodies in lupus remains unknown. Since double-stranded DNA (dsDNA) is a weak immunogen, other stimuli such as B cell superantigens or anti-idiotypic antibodies may provide an alternative mechanism for their production. The presence of regulatory determinants on autoantibodies might be revealed through their structural characterization, but they have eluded detection, perhaps because they may be three-dimensional and require closer analysis. In this report we cloned and sequenced the heavy chain variable region (VH) of a monoclonal anti-dsDNA antibody, mAb 3E10, derived from MRL/lpr mice with lupus nephritis previously shown to express an idiotype associated with nephritis in murine and human lupus. We now show that mAb 3E10 VH contains novel structural features unrelated to DNA binding which are shared only by a subset of autoantibodies expressed in murine lupus. These lupus autoantibodies can be distinguished from antibodies of non-autoimmune strains by the presence of a specific sequence at the junction of the diversity and joining genes combined with the use of variable region genes with conserved sequences in framework 1 (FR1) and FR3. The location of the novel sequences indicates the possibility of a three-dimensional solvent-exposed determinant located distant from the classical antigen binding site that could regulate their production, possibly through binding B cell superantigens or other infectious agents.

Wegener's granulomatosis in the elderly.

Wegener's granulomatosis is a systemic necrotizing granulomatous vasculitis in which the average age at onset is in the forties. The disease has an excellent response to treatment with cyclophosphamide. We proposed that the tendency to accept multisystem disease in elderly patients (greater than or equal to 60 years old) and a reluctance to administer aggressive therapy would be reflected in the diagnosis and treatment of Wegener's granulomatosis in the elderly, and that as a consequence, the delay in diagnosis and implementation of therapy could result in a needlessly higher morbidity and mortality rate for this population of patients.

Biosynthetic human GM-CSF modulates the number and affinity of neutrophil f-Met-Leu-Phe receptors.

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) modulates the function of mature neutrophils by priming for enhanced chemotaxis and oxidative metabolism in response to N-formyl-methionyl-leucyl-phenylalanine (f-Met-Leu-Phe). Our studies establish a relationship between f-Met-Leu-Phe receptor number and affinity and neutrophil chemotaxis and oxidative metabolism. A brief (5- to 15-min) exposure to physiologic concentrations of GM-CSF (10 pM to 100 pM) enhances f-Met-Leu-Phe-induced neutrophil chemotaxis by 85%, correlating with a rapid threefold increase (46,000/cell to 150,000/cell) in high-affinity neutrophil f-Met-Leu-Phe receptors. More prolonged incubation (1 to 2 hr) of neutrophils with GM-CSF is accompanied by a change to low-affinity f-Met-Leu-Phe receptors (Kd = 29 nM to Kd = 99 nM) concomitant with priming for enhanced neutrophil oxidative metabolism. Moreover, enhanced chemotactic responses to f-Met-Leu-Phe are no longer evident after more prolonged incubation of neutrophils with GM-CSF. These results show that a single lymphokine (GM-CSF) induces sequential changes in neutrophil f-Met-Leu-Phe receptor number and affinity that may enhance different physiologic responses.

Colony-stimulating factors and host defense.

Colony-stimulating factors are growth factors responsible for the proliferation and the maturation of bone marrow stem cells to fully differentiated granulocytes and monocytes. In addition to their effects on hematopoiesis, some colony-stimulating factors prime mature cells for enhanced chemotaxis, phagocytosis, and killing in response to physiologic stimuli. The action of colony-stimulating factors is mediated by growth factor receptors on precursor and mature effector cells. The results of studies of granulocyte-macrophage colony-stimulating factors in patients with the acquired immunodeficiency syndrome (AIDS) suggest a possible therapeutic role for colony-stimulating factors in augmenting mechanism of host defense.

Cellular immunity to intrinsic factor in pernicious anemia.

Cellular immunity to hog intrinsic factor was detected by a modified agarose-leukocyte migration test in 18 patients with pernicious amemia. Lymphocytes from 17 out of 18 patients with pernicious anemia gave positive responses to a concentrate of hog intrinsic factor; the intrinsic factor present in 1 mg. of this concentrate bound 128 ng. of vatamin B12. Six patients with atrophic gastritis, 7 with regional enteritis, and 9 out of 10 healthy adults did not respond to this preparation. No correlation existed between the presence of serum autoantibodies to intrinsic factor and in vitro lymphocyte responsiveness to intrinsic factor. The results demonstrate that cellular immunity to intrinsic factor concentrates is present in the majority of patients with pernicious anemia.

Neutrophil migration-inhibition activity produced by a unique T lymphoblast cell line.

Fifteen lymphoblast cell lines, including B cell, T cell, Null cell, and myeloblast cells, were examined for the production of human neutrophil migration-inhibition activity. Only one T lymphoblast cell line established from a patient with hairy cell leukemia produced a neutrophil migration-inhibition factor spontaneously and after stimulation with Con A and PHA.

Human polymorphonuclear leucocyte migration inhibitory factor. Evidence for antigen dependency.

Sudies were performed on human polymorphonuclear leucocyte migration inhibitory factor (PMN-MIF) to determine its antigen dependence. PMN-MIF produced by lymphocytes in response to purified protein derivative or coccidiodin was measured in an agarose gel system with buffy coat leucocytes as indicator cells. PMN-MIF activity contained in the lymphocyte supernatants uniformly disappeared when the supernatants were diluted 1:50 with medium; the inhibitory activity was only restored when the diluted supernatants were reconstituted with specific antigen. PMN-MIF isolated by polyacrylamide gel electrophoresis showed the same properties as PMN-MIF present in whole supernatants. This factor consistently migrated in the albumin region on gel electrophoresis. These data indicate that human PMN-MIF is antigen-dependent.

Effect of immunoglobulin G on the responsiveness of human neutrophils to soluble staphylococcal protein A-induced neutrophil migration inhibition factor from T-lymphocytes.

Staphylococcal protein A is a bacterial cell wall product that binds human immunoglobulin G and thereby interferes with opsonization and phagocytosis of Staphylococcus aureus by neutrophils. Phagocytic cells are also responsive to various non-immunoglobulin lymphocyte mediators. We utilized the detection of a newly recognized mediator, a neutrophil migration inhibition factor from T-lymphocytes (NIF-T), to show that aggregates of staphylococcal protein A and immunoglobulins G could inhibit the responsiveness of neutrophils to NIF-T. That such aggregates may alter the responsiveness of neutrophils to lymphocyte mediators that amplify or modulate phagocytic functions may have important pathogenetic implications in staphylococcal infection.