A missense mutation in the neutrophil cytochrome b heavy chain in cytochrome-positive X-linked chronic granulomatous disease.

A membrane-bound cytochrome b, a heterodimer formed by a 91-kD glycoprotein and a 22-kD polypeptide, is a critical component of the phagocyte NADPH-oxidase responsible for the generation of superoxide anion. Mutations in the gene for the 91-kD chain of this cytochrome result in the X-linked form of chronic granulomatous disease (CGD), in which phagocytes are unable to produce superoxide. Typically, there is a marked deficiency of the 91-kD subunit and the cytochrome spectrum is absent (X- CGD). In a variant form of CGD with X-linked inheritance, affected males have a normal visible absorbance spectrum of cytochrome b, yet fail to generate superoxide (X+ CGD). The size and abundance of the mRNA for the 91-kD subunit and its encoded protein were examined and appeared normal. To search for a putative mutation in the coding sequence of the 91-kD subunit gene, the corresponding RNA from an affected X+ male was amplified by the polymerase chain reaction and sequenced. A single nucleotide change, a C----A transversion, was identified that predicts a nonconservative Pro----His substitution at residue 415 of the encoded protein. Hybridization of amplified genomic DNA with allele-specific oligonucleotide probes demonstrated the mutation to be specific to affected X+ males and the carrier state. These results strengthen the concept that all X-linked CGD relates to mutations affecting the expression or structure of the 91-kD cytochrome b subunit. The mechanism by which the Pro 415----His mutation renders the oxidase nonfunctional is unknown, but may involve an impaired interaction with other components of the oxidase.     

NADPH-binding component of the respiratory burst oxidase system: studies using neutrophil membranes from patients with chronic granulomatous disease lacking the beta-subunit of cytochrome b558

The NADPH-binding site of the respiratory burst oxidase system of neutrophils has been proposed to be either at a cytosolic component or at the beta-subunit of cytochrome b558. In this study, affinity labeling of resting and stimulated membranes, the latter having been assembled by all of the oxidase components from both membrane and cytosol, was carried out using [32P]NADPH dialdehyde (oNADPH). Stimulation of human neutrophils with PMA greatly increased O2(-)- generating activity and caused considerable translocation of the cytosolic components p47phox and p67phox. Nevertheless, PMA stimulation did not produce a labeled band which included positions at 47, 67, and approximately 32 kD. The most intense band reflected a molecular mass of 84 kD regardless of the state of activation, but a labeled band was never found near the beta-subunit (91 kD) of cytochrome b558. This 84- kD protein was further confirmed in neutrophils of 14 patients with gp91phox-deficient X-linked chronic granulomatous disease. These results indicate that the NADPH-binding component is not recruited from the cytosol, and also, that a membranous redox component besides cytochrome b558 must be involved in the NADPH oxidase system.     

Cytochrome b deficiency in an autosomal form of chronic granulomatous disease. A third form of chronic granulomatous disease recognized by monocyte hybridization

Three patients (two sisters and a brother) in one family are described with chronic granulomatous disease. The granulocytes of these patients did not respond with a metabolic burst to various stimuli and failed to kill catalase-positive microorganisms. The magnitude of the cytochrome b signal in the optical spectrum of the patients' granulocytes was less than 4% of the normal value, whereas the amount of noncovalently bound flavin in these cells was normal. The mode of inheritance of the genetic defect in this family is autosomal because the granulocytes of both parents (first cousins) and a nonaffected sister of the patients expressed 70-80% of the normal cytochrome b signal, showed low-normal or subnormal oxidative reactions during stimulation, and did not display mosaicism in the stimulated nitroblue-tetrazolium slide test. Somatic cell hybridization was performed between the monocytes from the affected boy in this family with monocytes from either a cytochrome b-negative male patient with X-linked chronic granulomatous disease or a cytochrome b-positive male patient with the classic autosomal form of this disease. In both combinations, monocyte hybrids were observed with nitroblue tetrazolium reductase activity after stimulation with phorbol myristate acetate. This complementation of the oxidase activity required protein synthesis. Our results prove that the defect in this family is genetically distinct from that in the other two forms of chronic granulomatous disease. Moreover, our results also indicate that the expression of cytochrome b in human phagocytes is coded by at least two loci, one on the X chromosome and one on an autosome.     

A variant form of X-linked chronic granulomatous disease with normal nitroblue tetrazolium slide test and cytochrome b

Chronic granulomatous disease was diagnosed in a boy who suffered from severe generalized infections. Family investigations revealed the inheritance of the disease to be X-linked. However, unlike other cases of X-linked chronic granulomatous disease, the membrane oxidase of the neutrophils from this patient was not totally defective and sufficient activity was left to result in a normal phorbol myristate acetate-stimulated nitroblue tetrazolium slide test. Also, unlike the usual findings in X-linked chronic granulomatous disease, cytochrome b was present in normal amounts in the neutrophils from this patient. The cytochrome was normal, judged from its midpoint potential of -245 mV and its ability to bind CO. It is thus apparent that X-linked chronic granulomatous disease may result from at least two different defects and that the phorbol myristate acetate stimulated nitroblue tetrazolium slide test fails to detect some cases.     

Determination of Gaucher's disease phenotypes with monoclonal antibody

Discrimination between the three clinical subtypes of Gaucher's disease based on the molecular forms of beta-glucocerebrosidase detected by monoclonal antibody is described. In normal fibroblast extracts, cross-reacting material (CRM) to human placental glucocerebrosidase is detected at Mr approximately equal to 63 000, 61 000 and 56 000. In Type 1 Gaucher's disease, the major fibroblast CRM has a Mr approximately equal to 56 000,, with less CRM seen at 61 000 and 56 000. Type 3 fibroblast extracts have a single CRM form at Mr approximately equal to 63 000. No CRM is found in Type 2 Gaucher's disease fibroblasts with monoclonal antiglucocerebrosidase antibody 8E4.     

Use of lipophilic probes of membrane potential to assess human neutrophil activation. Abnormality in chronic granulomatous disease.

Previous studies using membrane potential sensitive probes have provided evidence that chemotactic factors elicit membrane potential changes in normal human neutrophils (PMN). In addition to stimulation of PMN motility, chemotactic factors also stimulate degranulation and superoxide ion (O-2) generation and it has been suggested that alteration of membrane potential activates these events (Korchak, H. M., and G. Weissmann. 1978. Proc, Natl, Acad, Sci. U. S. A. 75: 3818--3822). To further define the inter-relationship of these functions, studies were done with two indirect probes of membrane potential, 3-3''-dipentyloxacarbocyanine and triphenylmethylphosphonium ion (TPMP+) using PMN from normal subjects, from patients with abnormal O-2 production (chronic granulomatous disease [CGD]), and from patients with defective degranulation and/or chemotaxis (Cheddiak-Higashi syndrome and patients with elevated immunoglobulin (Ig)E and recurrent staphylococcal infections). The stimuli used were the chemoattractant N-formyl-methionyl-leucyl-phenylalanine (f-Met-Leu-Phe) and the secretagogues ionophore A23187 and phorbol myristate acetate (PMA). The results obtained with 3-3''-dipentyloxacarbocyanine and TPMP+ were comparable. The apparent membrane potential changes elicited by f-Met-Leu-Phe and PMA in normal PMN were reduced or entirely absent in PMN obtained from patients with CGD but normal in PMN from other patients. PMN from patients with CGD had normal calculated resting membrane potentials and normal responses elicited by the potassium ionophore valinomycin. The responses to calcium ionophore A23187 were only slightly impaired. The abnormality of the elicited response of CGD cells of f-Met-Leu-Phe and PMA could not be attributed to the absence of O-2, hydroxyl radical, singlet oxygen, or hydrogen peroxide acting on the probes. Instead this abnormality appears to be associated with a dysfunction in the normal molecular mechanism(s) stimulated upon neutrophil activation. The data suggest chemoattractant alteration of membrane potential in normal PMN is related to activation of oxidative metabolism but the relationship to chemotaxis and degranulation remains to be established.     

Chronic granulomatous disease: diagnosis and classification at the molecular level.

Chronic granulomatous disease (CGD) is caused by the failure of phagocytes to produce microbicidal derivatives of molecular oxygen, such as hydrogen peroxide. It is one of the best characterized of the phagocyte disorders and represents an important consideration in the differential diagnosis of recurrent infections. The clinical, biochemical, and molecular genetic aspects of CGD are reviewed in this context in this article.     

Treatment of ulcerative colitis and Crohn's disease with monoclonal antibody

Ulcerative colitis and Crohn's disease are nonspecific inflammatory diseases of unknown etiology. Recent immunological studies have shown that proinflammatory cytokines and adhesion molecules play an important role in the pathogenesis of ulcerative colitis and Crohn's disease. Therefore, monoclonal antibodies to proinflammatory cytokines and adhesion molecules are used to suppress the mucosal inflammatory response in experimental colitis and ulcerative colitis and Crohn's disease. Anti-TNF alpha antibody and anti-alpha 4 beta 7 integrin antibody are well-tolerated and effective for treatment of patients with Crohn's disease. This review described clinical features and immunopathophysiology of ulcerative colitis and Crohn's disease, proinflammatory cytokines and immunosuppressive cytokines and adhesion molecules involved in the pathogenesis of both disease, and treatment of both diseases with monoclonal antibodies.     

Heterogeneity among human collagenases demonstrated by monoclonal antibody that selectively recognizes and inhibits human neutrophil collagenase

The heterogeneity of human collagenases has been examined using a monoclonal antibody to neutrophil collagenase. This antibody inhibited collagenase activity and, when covalently coupled to Sepharose, bound both latent and active enzyme. Although human neutrophil collagenase was inhibited by the antibody, the activity of human skin and rheumatoid synovial collagenase was not significantly diminished in the presence of the antibody. Competitive inhibition studies also differentiated between these collagenases. Only human neutrophil collagenase effectively blocked the antibody in a competitive enzyme-linked immunosorbent assay while skin and rheumatoid synovial collagenase again failed to interact with the antibody. The unequivocal recognition of neutrophil collagenase as an immunologically distinct entity from other collagenases supports the hypothesis that neutrophil collagenase is a separate gene product from fibroblast or synovial collagenase.     

Targeting gene therapy for prostate cancer cells by liposomes complexed with anti-prostate-specific membrane antigen monoclonal antibody

Prostate-specific membrane antigen (PSMA) is a membrane-bound antigen expressed on the surface of prostate cancer cells, and this paper describes the use of an antibody against PSMA for targeting gene therapy. We coupled anti-PSMA monoclonal antibody with poly-L-lysine and then incubated it with plasmids. These complexes were then transfected with cationic liposomes into cells. The transfection efficiency of anti-PSMA- liposome complex was higher than that of normal IgG-liposome complex in PSMA-positive LNCaP cells. Furthermore, anti-PSMA-liposome complex containing a suicide gene, thymidine kinase, demonstrated a selective growth-inhibitory effect on LNCaP cells in vitro, but did not exert a significant effect on PSMA-negative cells. In an in vivo xenograft model of LNCaP cells in nu/nu mice, we administered the complexes via the tail vein. Judging on the basis of both 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal) staining and luciferase assay findings, a significant enrichment of plasmid DNA was observed in LNCaP xenografts with anti-PSMA-liposome complex in comparison with normal IgG-liposome complex. However, the distribution of plasmid DNA did not change substantially in any other organs including the liver, kidney, lung, and spleen. Moreover, in suicide gene therapy, anti-PSMA-liposome complex exerted a significant inhibitory effect on the growth of LNCaP xenograft, in contrast to normal IgG-liposome complex.     

Functional defect in neutrophil cytosols from two patients with autosomal recessive cytochrome-positive chronic granulomatous disease.

The kinetics of activation of the respiratory burst oxidase in the cell-free oxidase-activating system have been explained by a three-stage mechanism in which the membrane-associated oxidase components M: (a) take up a cytosolic factor S to form a complex M.S that is (b) slowly converted in the second stage to a precatalytic species [M.S]*, which finally (c) takes up two more (possibly identical) cytosolic components, C alpha and C beta, to successively generate [M.S]*C alpha, a low-activity (i.e., high Km) oxidase, and finally [M.S]*C alpha C beta, the ordinary (i.e., low Km) oxidase (Babior, B.M., R. Kuver, and J.T. Curnutte. 1988. J. Biol. Chem. 263:1713-1718). Studies with the cell-free oxidase-activating system from normal neutrophils and from neutrophils obtained from two patients with type II (autosomal recessive cytochrome-positive) chronic granulomatous disease (CGD) have suggested that (a) the defective element in the cytosol from patient neutrophils is S; (b) in normal neutrophil cytosol, S is limiting with respect to M; and (c) C alpha and C beta interact cooperatively with the activated precursor complex [M.S]*. It was further speculated that S might be identical to the nonphosphorylated progenitor of the phosphorylated 48-kD proteins that are missing in certain forms of CGD, and that other forms of type II CGD besides the one described in this report remain to be discovered.     

Inhibition of in vivo neutrophil transmigration by a novel humanized anti-CD11/CD18 monoclonal antibody

Leukocyte adhesion receptors, including the beta-integrin (CD11/CD18) family, play an important role in inflammation via their regulatory effects on leukocyte adhesion, transmigration, and function. A randomized, placebo-controlled, double-blind study was conducted in healthy volunteers to evaluate the in vivo effects of a humanized anti-CD11/CD18 monoclonal antibody, Hu23F2G, on leukocyte activation and transmigration. Neutrophil migration to a site of cutaneous inflammation in vivo, as measured by the skin chamber technique, was significantly reduced in subjects 24 hours after Hu23F2G administration. At 96 hours, neutrophil migration was not significantly different in subjects who received Hu23F2G or placebo. In contrast, delayed-type hypersensitivity (DTH) testing, which involves activation and migration of T lymphocytes and macrophages, was unaffected by the Hu23F2G treatment. These responses to Hu23F2G in vivo are similar to the clinical phenotype of leukocyte adhesion deficiency (LAD) type 1, a congenital disorder of CD18 deficiency. The in vivo properties of Hu23F2G suggest therapeutic potential for use in the treatment of acute non-infectious inflammatory disorders mediated predominantly by neutrophils.     

Monoclonal antibody characterization of a chymotrypsin-like molecule on neutrophil membrane associated with cellular activation.

Monoclonal antibody 1-15 (Ab 1-15), is a murine anti-human neutrophil (PMN) IgG1 that inhibits PMN effector responses to N-formyl-met-leu-phe (FMLP) and phorbol myristate acetate. In this study, the effects of Ab 1-15 on PMN membrane-related functions were characterized: Ab 1-15 inhibited PMN superoxide (O-2) response to FMLP by 60% (P less than 0.005) without effect on the onset or duration of O-2 production. This inhibition of O-2 response was associated with a significant inhibition of PMN chymotrypsin-like, but not trypsin-like, protease activity. Cell fractionation studies indicated the presence of an Ab 1-15 inhibitable, chymotryptic neutral protease activity in PMN membranes. In studies of Ab 1-15 effects on membrane-related second messenger pathways, Ab 1-15 augmented both FMLP- and isoproterenol-induced intracellular cAMP accumulation, whereas alpha-chymotrypsin decreased PMN cAMP response to these stimuli. Our data suggest that the function-inhibiting, anti-PMN monoclonal Ab 1-15 defines a PMN chymotryptic enzyme on the membrane surface that is involved in regulation of two membrane-related functions, O-2 generation and cAMP generation.     

Beta 2-microglobulin determined by radioimmunoassay with monoclonal antibody

In this sensitive radioimmunoassay for beta 2-microglobulin (beta 2-M) involving a commercially available monoclonal antibody, we used a second monoclonal antibody, produced in our laboratory, for affinity-chromatographic purification of beta 2-M. Both monoclonal antibodies bound to all of the charge isomers of beta 2-M identified by two-dimensional gel electrophoresis. Polyethylene glycol was used to separate the phases after incubation for 3 h at room temperature. Sensitivity was 0.25 ng of beta 2-M. Within-assay CVs were less than 5.4%, between-assay CVs less than 7.3%. Analytical recovery was 95-102%. The reference interval was 1.2-2.2 mg/L for 49 healthy subjects. The correlation coefficient for comparison with a polyclonal antibody assay was 0.997 for 44 patients. In a study correlating serum beta 2-M and creatinine concentrations with glomerular filtration rate for 50 patients, correlation coefficients for log-log transformed data were -0.94 and- 0.95, respectively. Concentrations of beta 2-M were increased in serum of patients with imparied renal function and also in patients with normal renal function who had disorders involving the immunologic response. We found no clear-cut advantage of measuring serum beta 2-M over serum creatinine in the estimation of glomerular filtration rate.     

Autoantibodies, including antibasement membrane antibody, in patients with selective IgA deficiency

Laboratory data are presented on 48 patients with selective IgA deficiency. Sixty percent of the patients had autoimmune diseases or related disorders. We found antibasement membrane antibody (ABMA) in the sera of four IgA deficient patients and the incidence of ABMA seemed to be related to clinical symptoms. The incidence of various other antibodies was found to be increased in selective IgA deficiency. This phenomenon might be derived from the lack of local immune system. Inadequate IgA barrier might permit the exessive gastrointestinal absorption of food antigens or autoimmunogens in metabolic products which are excreted into the gut lumen.     

Identification of a thermolabile component of the human neutrophil NADPH oxidase. A model for chronic granulomatous disease caused by deficiency of the p67-phox cytosolic component.

Mild heating of human neutrophils inactivates the respiratory burst oxidase, producing a defect in superoxide production and bacterial killing comparable to that seen in patients afflicted with chronic granulomatous disease (CGD). We have now investigated the mechanism and specificity of this inactivation by examining the effect of mild heating on the known oxidase components: the membrane-bound subunits of the cytochrome b558 (gp91-phox and p22-phox) and the two cytosolic oxidase factors (p47-phox and p67-phox). Heating (46 degrees C for 7.5 min) caused intact neutrophils to lose greater than 85% of their capacity to produce superoxide, a defect which was localized to the cytosolic, but not the membrane, fraction. Complementation studies with CGD cytosols deficient in either p47-phox or p67-phox suggested that the defective component of heat-inactivated cytosol was p67-phox. This was confirmed by experiments showing that recombinant p67-phox, but not p47-phox, exhibited lability at 46 degrees C and completely reconstituted oxidase activity of heat-treated cytosol. These studies indicate that mild heating of either intact neutrophils or normal neutrophil cytosol results in a selective inactivation of p67-phox, providing a model oxidase system for the extremely rare p67-phox-deficient form of CGD.     

Differences in the characteristics of human monoclonal and polyclonal anti-D as revealed by immunochemical investigations: human monoclonal antibodies share specificities with natural antibodies

To determine the basis of the tissue cross-reactions shown by some human monoclonal anti-Rh D antibodies, we have investigated the tissue reactivities of 48 further human monoclonal antibodies (mAb) against D and other Rh antigens, and compared them with those of normal and anti-D sera and immunoglobulin preparations, and affinity-purified polyclonal anti-D antibodies. Although we were unable to detect any tissue reactivities associated with the D-binding fraction of polyclonal antisera or prophylactic immunoglobulin, the non-erythroid cell types identified by the tissue-reactive human anti-Rh mAb of both IgM and IgG class were those recognized by antibodies present in both normal and anti-D sera. These results indicate: (a) that the tissue specificities of human anti-Rh mAb are similar to those of natural antibodies, and (b) that there are immunochemical differences between polyclonal and monoclonal anti-D antibodies, at least of IgG class, which may be relevant to the use of the latter in the prevention of haemolytic disease of the new-born by immune prophylaxis.     

Chronic T cell leukemia with a NK phenotype reacting with anti-myelin-associated glycoprotein (MAG) mouse monoclonal antibody

We describe a patient demonstrating chronic T cell leukemia with a natural killer (NK) phenotype. The leukemic cells could be stained by OKT 3 (T cells), anti-Leu-7 and anti-myelin-associated glycoprotein (MAG) (NK cells) but not anti-Leu-11 monoclonal mouse antibody (activated NK cells). Fresh mononuclear cells showed a very low NK activity, although this activity returned to normal levels after 18 days incubation with interleukin-2 and some stimulants. It was not known why the NK activity of fresh mononuclear cells was low. This report is the first on leukemia characterized by anti-MAG monoclonal antibody.