Properties of solubilized Fc gamma-receptors from psoriatic scales

Extracts from psoriatic scales, prepared using Tris-HCl buffer containing ethylenediaminetetraacetatic acid (EDTA) and 2-mercaptoethanol (ME), agglutinated erythrocytes (E) sensitized with IgG antibodies (A) (EA), but not E or E sensitized with F(ab')2-fragments of IgG. The agglutination was inhibited by IgG and Fc fragments of IgG, but not by IgA, IgM or F(ab')2-fragments of IgG. Partially reduced and alkylated IgG did not inhibit the agglutination, indicating that an inter-heavy-chain disulphide-linked Fc region is required for binding of FcR. The extracts inhibited EA, but not E or EAC rosette formation with mononuclear cells. The results strongly indicated that the extract contained functionally active FcR. The agglutinating activity of the extract was not affected by treatment with periodic acid or formaldehyde, whereas heat reduced the activity. Using a monoclonal antibody (B1D6) a functionally active 40 kDa FcR with low affinity for native IgG was purified from the scale extract. The extracts also contained FcR activity not recognized by B1D6.

Who gets a second primary cancer after gastric cancer surgery?

Eleven patients presented with a second primary cancer during follow-up after surgery for gastric carcinoma. In these patients the serum concentrations of C1-INH and IgG prior to gastric cancer surgery were similar to those of 53 patients with recurrence of gastric cancer. In these two groups, the preoperative C1-INH concentrations were higher and IgG lower (P less than 0.001 and P less than 0.05) when compared to 36 patients alive and disease-free 5 years after surgery. The median time between surgery and signs of recurrence was 11 months, whereas the median time until signs of the second primary cancer was 4 years. A patient with gastric carcinoma who pre-operatively has high C1-INH and low IgG is liable either to have recurrence or to develop a second primary cancer. Our data indicate that these variables represent a cancer susceptibility feature appropriate to the host.

The ontogenesis of Fc gamma receptors and complement receptors CR1 in human peripheral nerve

The ontogenesis of Fc gamma receptors (FcR) and C3b/C4b receptors (CR1) was studied in peripheral nerves from ten fetuses aged from 20 to 38 weeks using immunohistochemical and functional assays. Monoclonal antibodies (mAbs) against FcR and CR1 stained nerve fibers at 10 weeks of gestation and the staining intensity increased during nerve maturation. FcR and CR1 are probably expressed on Schwann cells and are early markers during the development of peripheral nerves. Functional FcR activity was detected in nerve sections before initiation of myelination, which occurs at approximately 18-19 weeks, whereas functional CR1 activity was found in the sections after myelination. Functional CR1 activity may, therefore, be related to myelin. The ontogenesis of FcR and CR1 was also studied on Schwann cells in culture from three fetuses aged 14, 16 and 19 weeks, using immunofluorescence technique with mAbs. The FcR and CR1 are lost on cultured Schwann cells. This suggests that the receptors are not intrinsic to the cells or that Schwann cells require axonal contact for the expression of FcR and CR1.

Glomerular CR1 express in situ cofactor activity for degradation of C3b

Adherence of sheep erythrocytes (E) sensitized with IgM antibodies (A) and C3b (EAC3b) to C3b/C4b receptors (CR1) in cryostat sections of human renal glomeruli was studied using the closed chamber technique. The adsorption was stable for at least 3 h at 37 degrees C. In the presence of purified factor I, the indicator cells, however, detached from the sections after 30 min at 37 degrees C. Factor H was not required. The release was not due to loss of CR1 activity in the tissue. The detached indicator cells were negative in the immune adherence test and were agglutinated by antibody to C3d, but not by antibody to C3c. Western blot of the detached indicator cells revealed the presence of C3d and C3c was found in the chamber fluid. Accordingly, detachment of the indicator cells was due to degradation of C3b to C3d with the release of C3c into the chamber fluid. Protease inhibitors did not prevent the detachment of the indicator cells. EAC3b incubated with sections of renal glomeruli preincubated with anti-CR1 antibody were not degraded. The results therefore indicate that CR1 in situ in renal glomeruli can provide the necessary cofactor activity for factor I-mediated degradation of C3b to C3d and C3c.

Peripheral nerve CR1 express in situ cofactor activity for degradation of C3b

Adsorption of sheep erythrocytes (E) sensitized with IgM antibodies (A) and C3b (EAC3b) to C3b/C4b receptors (CR1) in cryostat sections of human myelinated nerves was studied using the closed chamber technique. The adsorption was stable for at least 3 h at 37 degrees C. In the presence of purified factor I, the indicator cells detached from the sections after 40 min at 37 degrees C. Factor H was not required. The release was not due to loss of CR1 activity in the sections. The detached indicator cells were negative in the immune adherence test and were agglutinated by antibody to C3d, but not by antibody to C3c. Western blot of the detached indicator cells revealed the presence of C3d and C3c was found in the chamber fluid. Accordingly, detachment of the indicator cells was due to degradation of C3b to C3d with the release of C3c into the chamber fluid. Protease inhibitors did not prevent the detachment of the indicator cells. EAC3b incubated with sections of myelinated nerves pre-incubated with anti-CR1 antibody or with sections of unmyelinated nerves which contain functionally inactive CR1 were not degraded. The results therefore indicate that CR1 in situ in myelinated nerves can provide the necessary cofactor activity for factor I-mediated degradation of C3b to C3d and C3c.

Serum C1-esterase inhibitor, an essential and independent prognosticator of gastric carcinoma

The preoperative concentrations of IgG were lower (P less than 0.002) and the concentrations of C4 and C1-INH higher (P less than 0.01 and P less than 0.001) in 29 patients with recurrence after potentially curative resection of gastric carcinoma, than in 31 patients alive and disease-free 5 years after surgery. These differences between the two groups of patients were consistent within each of six groups of disease extent. In each of the two groups of patients, the preoperative concentrations of IgG, C4 and C1-INH had no significant variation with the extent of disease (P greater than 0.05 or greater). Of our variables, C1-INH was the most potent prognosticator and discriminated between patients with and without recurrence with 80% accuracy. Furthermore, the predictive prognostic value of C1-INH at the time of surgery was superior to the prognostic value of the extent of disease (F values 27.00 and 12.69). Apparently, the preoperative C1-INH concentration is an essential and independent prognostic parameter of gastric carcinoma. We assume that C1-INH reflects an additional prognostic feature appropriate to the tumour or the host. Our finding that the interval between surgery and death from recurrence had an inverse relation to the preoperative C1-INH concentration also supports this assumption.

Solubilization of human peripheral nerve Fc gamma receptors and purification of a functional 40 kDa receptor

Extracts from myelinated and unmyelinated nerves, prepared using Tris-HCl buffer with EDTA and ME, contained functionally active receptors for the Fc region of IgG (FcR). This was evident from the results obtained in indirect haemagglutination and rosette inhibition assays. Using a monoclonal antibody, a functional active 40-kDa FcR was purified from the nerve extracts. The receptor was a single-chained glycoprotein with low affinity for native IgG, apparently belonging to the FcRII family. In addition, peripheral nerve extracts contain FcR not recognised by the monoclonal antibody.

In situ localization of interferons in psoriatic lesions

An indirect immunofluorescence technique, using murine monoclonal antibodies (MoAbs) against human IFN-alpha and human IFN-gamma was used to study IFNs in cryostat sections from psoriatic skin lesions. The IFNs were more pronounced in sections from highly active psoriasis than in sections from stationary psoriasis. In highly active psoriatic lesions IFN-alpha was localized to keratinocytes is stratum basale, to some epidermal dendritic cells, probably Langerhans cells, and to some mononuclear cells in dermis. IFN-alpha was usually not detected in sections from stationary psoriasis. IFN-gamma was localized to stratum corneum, to keratinocytes around microabcesses and to mononuclear cells in the dermal cell infiltrates, predominantly in highly active psoriatic lesions. Both IFN-alpha and IFN-gamma were localized to some endothelial cells in the papillary dermis. The MoAbs did not stain sections from unaffected skin from patients with psoriasis or sections from healthy individuals. The findings indicate that the IFN system in the skin may be of significance in the pathophysiology of psoriasis.

Associated disorders in myasthenia gravis: autoimmune diseases and their relation to thymectomy

The prevalence of myasthenia gravis (MG) in the counties of Hordaland and Sogn & Fjordane on January 1, 1984 was 9.6 per 100,000 inhabitants. Other autoimmune diseases were found in 11 out of 48 MG patients. The occurrence of autoimmune thyroiditis (5 patients, 10.4%) and systemic lupus erythematosus (4 patients, 8.3%) in the MG patients was clearly higher than that reported in the general population. Rheumatoid arthritis was found in 2 patients (4.2%). The autoimmune diseases were mainly recorded among the nonthymectomized MG patients. In addition to those with definite diseases of autoimmune nature, 3 other MG patients had thyroid antibodies and 1 had antinuclear factor without clinical evidence of autoimmune disease. Seven MG patients (14.6%) had unspecific arthralgia during active periods of MG. Two MG patients had ankylosing spondylitis.

Purification of a functional 40 kD human placental Fc gamma-receptor using a monoclonal antibody

F(ab')2-fragments of a mouse monoclonal antibody (B1D6) reacting with placental receptors for the Fc part of IgG (FcR) were used as affinity reagents for the purification of an antigen from placental extract (PE). The antigen agglutinated ovine erythrocytes (E) sensitized with rabbit antibodies (A) (EA), but not E or E sensitized with F(ab')2-fragments. It reduced the EA rosette-formation with mononuclear cells and the binding of soluble immune complexes to placental tissue. The antigen bound to aggregated IgG and Fc-fragments of IgG, but not to native IgG or F(ab')2-fragments of IgG. The data indicate that the purified antigen possesses FcR activity with low affinity for IgG. SDS-PAGE and Western blot showed one distinct band of approximately 40 kD. The electrophoretic mobility did not change after reduction and the band reacted with concanavalin A indicating that the FcR are single-chained glycoproteins.

Isolation and characterization of complement receptors CR1 from human peripheral nerves

Extracts from myelinated and unmyelinated nerves, prepared using Nonidet P-40, contained receptors for C3b/C4b (CR1). Extracts from myelinated nerves inhibited EAC3b rosette formation with peripheral blood leucocytes and agglutinated EAC3b, whereas extract from unmyelinated nerves did not. Rosette formation with EAC3bi or EAC3d was not affected. CR1 in extracts from myelinated nerves also expressed decay-accelerating activity of the alternative pathway C3 convertase and cofactor activity in factor I-mediated cleavage of C3b, whereas CR1 in extract from unmyelinated nerves did not. Monoclonal anti-CR1 antibodies, but not monoclonal anti-CR2 (C3d receptors) or anti-CR3 (C3bi receptors) antibodies inhibited the functional activities. Accordingly, CR1 are the only C3 receptor present in the extracts and only CR1 in myelinated nerve extracts are functionally active. CR1 in both myelinated and unmyelinated nerve extracts had a molecular weight of approximately 190 kDa. The electrophoretic mobility did not change after reduction and the 190 kDa band was stained by concanavalin A, indicating that the CR1 are single-chained glycoproteins. Binding to lentil lectin-Sepharose 4B further sustained the glycoprotein nature of the CR1. Periodic acid abolished functional activities of CR1, whereas trypsin and heat did not, indicating the functional significance of the carbohydrate moiety. That CR1 are functionally active in myelinated nerves, but not in unmyelinated nerves, may therefore be due to differences in the carbohydrate moiety. The cofactor and decay-accelerating activities of CR1 may be of significance in the pathogenesis of demyelinating polyneuropathies by limiting complement activation.

Localization of Fc gamma receptors and complement receptors CR1 on human peripheral nerve fibres by immunoelectron microscopy

The localization of receptors for the Fc part of IgG (Fc gamma R) and for the complement C3b/C4b components (CR1) on human peripheral nerve fibres was investigated by indirect immunoperoxidase staining of frozen nerve sections with monoclonal antibodies. Transmission electron microscopy revealed that Fc gamma R and CR1 are localized to the entire surface membrane and inner membrane (axolemma) of the Schwann cell. Myelin and axons were not stained. The presence of Fc gamma R and CR1 in human Schwann cells adds further evidence for the immunocompetence of these cells.

Effect of hyperbaric oxygen treatment on immunological parameters in multiple sclerosis

Hyperbaric oxygen (HBO) treatment has been reported to cause amelioration of clinical symptoms in patients with multiple sclerosis (MS). We have treated 10 MS patients with hyperbaric oxygen (100% O2 at 2 atmospheres absolute for 90 min daily for a total of 20 exposures), and performed immunological studies on peripheral blood and cerebrospinal fluid (CSF). After treatment there was a significant increase in total and helper T lymphocyte counts in peripheral blood, as well as an increase in both E, Fc gamma and C3b receptor-bearing lymphocytes. The responses to the mitogens PHA, con A and PWM were unchanged. Granulocytes showed an increased proportion of Fc gamma receptor and C3b receptor positive cells after treatment. The O2 consumption of granulocytes also increased, but phagocytosis, as measured by chemiluminescence, was unchanged. Serum IgA levels were slightly increased, while IgG and IgM concentrations remained unchanged after treatment. Cerebrospinal fluid cell counts, protein and IgG concentrations, as well as IgG indexes remained unchanged.

The acute effect of passive Heymann nephritis on renal blood flow and glomerular filtration rate in rats

The acute renal hemodynamic changes during induction of passive Heymann nephritis (PHN) may be of importance for the understanding of the pathogenesis of this model. We studied the renal blood flow (RBF) and glomerular filtration rate (GFR) during and after infusion of anti-FxlA into the left renal artery of rats for 10 min. 3 control groups were given 0.9% NaCl, 1 and 2 mg of normal rabbit IgG, respectively. The experimental groups were given 1 and 2 mg IgG fraction of anti-FxlA. Compared to controls, both RBF and GFR were substantially reduced during the first 20-30 min after infusion and remained unaltered for the rest of the observation period. After 20-30 min, RBF in the 1-mg group was 4.8 +/- 0.77 ml/min/g kidney weight versus control, 6.4 +/- 1.23 (NS), and in the 2-mg group, 3.5 +/- 0.65 ml/min/g versus control, 6.4 +/- 1.07 (p less than 0.05). Similarly, in the 1-mg group, GFR was 0.40 +/- 0.08 ml/min/g versus control, 0.76 +/- 0.11 (p less than 0.05), and in the 2-mg group, 0.14 +/- 0.05 versus control, 0.77 +/- 0.12 (p less than 0.0001). The reductions were greater in the 2-mg than in the 1-mg infused experimental groups, but this difference did not reach statistical significance. Immunofluorescence showed typical granular fluorescence of rabbit IgG along the glomerular basement membrane, and electron microscopy showed subepithelial immune deposits. This indicates that in the initial phase of PHN, corresponding with the formation of immune complexes, a pronounced fall in RBF and GFR occurs.

Serum opsonins to serogroup B meningococci in meningococcal disease

The opsonic activity to serogroup B meningococci (B:15:P1.16) was measured in sera from 101 patients with meningococcal disease using a chemiluminescence method. On admission to hospital the opsonic activity was lower in 12 patients who died than in survivors (p = 0.0007). A close association was observed between the opsonic activity and the duration of symptoms before admission, the severity of the disease, and the levels of IgG antibodies to the outer membrane complex (15:P1.16). The opsonic activity was low in 2 premorbid sera compared to healthy controls. The mean opsonic activity peaked 2 weeks after admission and was still high 3-5 years later. Meningococcal strains of different serogroups, serotypes and subtypes induced a similar increase in opsonic activity to B:15:P1.16 meningococci. No increase in activity was observed in sera from patients with meningitis and septicemia caused by other bacteria. Serum opsonins seem to be of significant importance in the host defence against serogroup B meningococci.

Effect of fasting on lysosomes in kidney cortex of glomerulonephritic rats

The effect of food restriction (FR) on the kidney cortex lysosomes prepared by rate and isopycnic zonal centrifugation was studied in rats with passive Heymann glomerulonephritis (PHN). FR reduced the renal mass by 41%, but the capacity for handling of labelled endocytosed proteins by the lysosomes was not different from fed PHN rats. While PHN with heavy proteinuria increased the recovery of lysosomal enzymes in the large lysosomes located in the proximal tubule, no changes were observed in FR-PHN rats in spite of significant proteinuria. The density of the small lysosomes was significantly shifted/reduced (from 1,200 and 1,235 g/ml to 1,185 and 1,225 g/ml, respectively) in both fed and FR-PHN rats, suggesting that the handling of extra loads of protein may enhance the absorptive function of small lysosomes found in the lower part of the nephron. FR reduced the mechanical fragility of lysosomes in the kidney cortex of PHN-rats. The highly increased urinary excretion of lysosomal enzymes in fed PHN rats was not observed in FR-PHN rats. As a conclusion, FR reduces both the fragility of lysosomes and the proportion of digestive enzymes in fragile lysosomes. These lysosomal enzymes may be of pathogenic importance in PHN causing cell damage when liberated from disrupted lysosomes.

Class and IgG subclass distribution of antibodies against peripheral nerve myelin in sera from patients with inflammatory demyelinating polyradiculoneuropathy

An enzyme-linked immunosorbent assay (ELISA) was used to quantify antibodies against peripheral nerve myelin (PNM) in sera from 90 patients with Guillain-Barré syndrome (GBS) and from 70 patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Fifty-nine percent of the patients with GBS and 51% of the patients with CIDP had increased levels of anti-PNM antibodies. Antibodies were also found in 0%-14% of sera from patients with other neurological diseases and in 8% of normal blood donors. Mean levels of IgG, IgM and IgA anti-PNM antibodies were increased in sera from patients with GBS, and mean IgG and IgA anti-PNM antibody levels were increased in sera from patients with CIDP when compared with sera from normal blood donors. The mean IgG anti-PNM antibody response observed in patients with GBS or CIDP was dominated by the IgG1 and IgG3 subclasses.

Plasma exchange in myasthenia gravis: changes in serum complement and immunoglobulins

Serum concentrations of C4, IgG, IgA, and IgM were followed in 8 selected patients with myasthenia gravis (MG) during a 5-day course of plasma exchange (PE), using donor plasma as a replacement solution. C3 activation products (C3b, iC3b and C3c) and the terminal SC5b-9 complement complex were measured in 4 of the patients. All patients improved during the treatment, including 2 patients without detectable antibodies to AChR in serum. The main findings of the study were marked complement activation and an approximately 50% fall in the serum concentrations of IgM and C4 during PE, independent of the concentrations in the donor plasma. The concentrations of IgG and IgA did not change significantly. The fall in C4 during PE is presumably caused by C4 consumption. We postulate that the fall in IgM is an effect of a complement-induced vasodilatation and that PE-induced complement consumption may influence the effect of PE in patients with MG.

Complement receptors CR1 on human peripheral nerve fibres

Receptors for C3 and C4 in human peripheral nerve tissue were studied by examining the adherence of complement (C) coated erythrocytes (E) and by using monoclonal antibodies against epitopes on the receptors for C3b (CR1), C3d (CR2) and C3bi (CR3). E (erythrocyte)-bearing C3b or C4b adhered to sections of myelinated peripheral nerves and the binding was inhibited only by anti-CR1 antibodies. By immunofluorescence, anti-CR1 antibodies stained the nerve fibres, whereas anti-CR2 and anti-CR3 antibodies did not. The staining was apparently localized to the Schwann cell membrane. E-bearing C3bi or C3d did not adhere to myelinated or unmyelinated nerves. CR1 are therefore the only C3 receptors expressed in human peripheral nerves. E-bearing C3b or C4b did not adhere to unmyelinated nerves from adults or to nerves from fetuses at a gestational age of approximately 21 weeks, whereas monoclonal anti-CR1 antibodies stained myelinated, unmyelinated and fetal nerves equally well. The results indicate that CR1 in unmyelinated and fetal nerves are either functionally inactive or express a lower affinity for C3b/C4b than CR1 in myelinated nerves. There were no significant differences in the binding of E-bearing C3b or C4b to myelinated peripheral nerves from 50 individuals, indicating that CR1 activity is not distributed phenotypically.

Changes in lysosome populations in the rat kidney cortex induced by experimental proteinuria

1. Experimental proteinuria (262.9 mg protein/24 hr urine) was induced in rats by repeated intraperitoneal injections of BSA. 2. Hypertrophy of the kidney cortex was significant 8 days after the start of the BSA injections, and the activities of lysosomal enzymes in kidney cortex and urine were significantly higher in proteinuric compared to nonproteinuric rats. 3. Lysosome populations in the kidney cortex were examined by rate sedimentation of the homogenate and by rate zonal and isopycnic centrifugation of the lysosome-rich ML fraction. 4. The activity of lysosomal enzymes in the kidney cortex increased slightly, essentially in the large, fragile lysosomes mainly recovered from the proximal tubule. 5. Proteinuria induced a shift/reduction in the density of small lysosomes from 1.235 and 1.20 g/ml to 1.225 and 1.185 g/ml, respectively. 6. Proteinuria induced a new population of small lysosomes (density 1.185 g/ml) enriched in cathepsin D.

IgG Fc receptors in sera from patients with rheumatoid arthritis and systemic lupus erythematosus

A murine monoclonal antibody to receptors for IgG (FcR) in human placenta was used in a competitive ELISA to demonstrate soluble FcR in human sera. Sera from 20 blood donors, 30 patients with systemic lupus erythematosus and 50 patients with rheumatoid arthritis were examined. Soluble FcR were demonstrated in all sera. However, significantly lower amounts of FcR were demonstrated in the patient groups as compared to blood donors. Whether this is due to increased consumption or reduced production has to be further investigated. The findings may be of significance in the pathogenesis of these diseases.

Effect of UV radiation on interferon, immunoglobulins and complement components in serum from healthy individuals

An infectivity inhibition micro-method was used to detect interferon (IFN) in sera from 20 healthy individuals before and after UVA irradiation, and in sera from 22 healthy individuals before and after UVB irradiation. The serum levels of IFN, immunoglobulins (Ig) and complement components (C) were examined before irradiation, after 10 and 20 exposures, and 4 weeks after irradiation. The median serum IFN level in both the UVA and the UVB group increased significantly during irradiation, most markedly during the 10 first exposures. Four weeks after irradiation the median IFN level was reduced in both groups, but had not reached the pre-irradiation levels. The IFN level was unchanged or reduced in 2 individuals in the UVA group and in 5 individuals in the UVB group. Characterization experiments indicated the presence of both acid-stable and acid-labile IFN-alpha and IFN-gamma. The mean serum IgG concentration was significantly reduced 4 weeks after UVA irradiation, whereas IgA, IgM, C3 and C4 were not affected. The mean serum concentrations of IgG and C4 were significantly reduced 4 weeks after UVB irradiation, whereas the mean concentrations of IgM and C3 were significantly increased. The concentration of IgA was not affected.

In situ demonstration of Fc gamma-receptors in human chronic marginal and apical periodontitis

The distribution of receptors for the Fc portion of IgG (Fc gamma R) in chronic marginal and apical periodontitis were studied by using a monoclonal antibody against placental Fc gamma R and soluble immune complexes as indicators. Cryostat sections were used in indirect immunofluorescence technique. Fc gamma R were detected on varying numbers of cells in the inflammatory cell infiltrates, on endothelial cells of certain vessels and in fibrous tissue. In chronic marginal periodontitis Fc gamma R were also observed on cells within the oral gingival epithelium (OGE) and the pocket epithelium (PE). There was a distinct fluorescence in stratum spinosum and occasionally in stratum basale of OGE and in the coronal portion of the PE. Fc gamma R on Langerhans cells could not be demonstrated. In apical periodontitis Fc gamma R were also detected on cells within the epithelium. In some cases epithelium in periapical cysts was positive. Soluble immune complexes bound to morphologically similar, but fewer cells compared to the monoclonal antibody against Fc gamma R. The results indicate that Fc gamma R are generally expressed on cells in inflamed tissue. Thus, this presence of Fc gamma R on certain specialized cells such as endothelial cells and keratinocytes, may endow these cells with functions previously thought to be restricted to cells of the lymphoreticular system.