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PubMed1988

Complement fixation by Brazilian Pemphigus foliaceus autoantibodies.

This study was undertaken to determine if Brazilian Pemphigus foliaceus (BPF) autoantibodies will fix complement as do P. vulgaris (PV) autoantibodies. When sections of human skin were examined following indirect immunofluorescence (IF) staining, BPF autoantibodies reacted with the upper layers of epidermis, while PV autoantibodies were reactive with the lower layers. When tissue culture epidermal cells were used for indirect IF, BPF autoantibodies were not detected after plating until 24 h, while PV autoantibodies reacted within 18 h of plating. Using complement IF staining methods, BPF autoantibodies were found to fix C1q, C4 and C3 to whole skin sections in an intercellular pattern and to the surface of cultured keratinocytes. Although reactive with different epidermal cell surface antigens, autoantibodies in BPF will fix complement in a fashion similar to autoantibodies in PV.

Animals↗
PubMed1989

[A method of isolating C1q from human serum and its use in the solid-phase immunoenzyme determination of immune complexes].

C1q was isolated from human serum by dialysis in 0.24 M EDTA, followed by affinity chromatography on immobilized IgG and removal of IgG traces in a column with anti-IgG antibodies. Microplates were coated with C1q in PBS at 10-20 mg/l, nonspecific binding sites were saturated with human serum albumin. The sera were diluted 16-fold in 0.05 M PBS, 0.01 M EDTA, 0.05% Tween. After incubation with diluted samples the plates were treated with horseradish peroxidase--anti-human IgG conjugates. Enzymic activity was measured by adding p-phenylenediamine (0.2 g/l) in acetate buffer, pH 5.9, containing 0.05% H2O2. The sensitivity of the assay ranged between 2.5 and 300 mg/l.

Antigen-Antibody Complex↗
PubMed1989

Probing the C4-binding site on C1s with monoclonal antibodies. Evidence for a C4/C4b-binding site on the gamma-domain.

The catalytic site for C4 of C1s has been presumed to consist of a C4-binding domain and a proteolytic domain. A mAb to C1s, M81, blocked C4 activation and C4 binding to C1s. M81 recognized the H chain of C1s. Using M81 as a probe, we tried to define C4-binding site on C1s. Plasmin digestion of C1s generated four products of Mr 58,000 (P1), 48,000 (P2), 37,000 (P3), and 27,000 (P4). These products, except for P2, all possessed a 26,000-Da H chain fragment (26k-HF) connected to variable-sized L chain pieces. 26k-HF alone had an ability to interact with M81. Amino-terminal amino acid analysis of 26k-HF mapped the epitope for M81 to domain IV and/or V of gamma-domain of C1s. The gamma-domain therefore contains the C4-binding site. The confirm and further elucidate the role of the C4-binding site for C4, we used a substrate-blotting technique in which labeled C4 was incubated with nitrocellulose membrane-fixed C1s and its fragments. C4 was successfully blotted onto C1s and P1, but not P2-P4; i.e., further degradation of the L chain led to the loss of C4-binding. During the incubation, most of the added C4 was converted to C4b. The binding was augmented, if the proteolytic activity of C1s and P1 was blocked, so that the added C4 remained intact. Although C4b also bound to C1s and P1, its binding was less effective and abolished by the addition of cold C4. Based on these results, the gamma-domain and the L chain constitute the catalytic site of C1s to activate C4 to C4b. Moreover, the generated C4b, although it still has weak affinity for C1s, can be replaced by newly coming C4.

Antibodies, Monoclonal↗
PubMed1989

Genetic studies of low-abundance human plasma proteins. XIII. Population genetics of C1R complement subcomponent and description of new variants.

Isoelectric focusing and immunoblotting reveals considerable biochemical and genetic variation in the C1R subcomponent of the first complement component. The nature of the intraindividual biochemical variation can be explained by differences in sialic acid content because after digestion with neuraminidase the terminal sialic acids are removed to yield a single major band corresponding to the C1R polypeptide. Plasma samples from a large number of different ethnic groups, consisting of U.S. whites, U.S. blacks, Nigerian blacks, and Inuit, Aleut, and Amerindian populations from the Western Hemisphere have revealed genetically determined charge variation with heterozygous phenotypes consisting of two major asialo bands, indicating that the underlying variation is not due to variation in sialic acid content. Two previously reported common alleles, C1R*1 and CIR*2, have been observed in all studied populations, the notable exception being the Dogrib Indian population, which is devoid of the C1R*2 allele. Several new alleles--designated C1R*3, C1R*4, C1R*5, C1R*6, and C1R*7-have been observed, with variable frequencies ranging from the occurrence in a single individual and related family members to the polymorphic occurrence of certain alleles in several populations. Of these new alleles, the C1R*5 is of considerable interest in population and anthropological genetics studies. The C1R*5 allele is widely distributed, at a frequency of .03 to .17, in all of the North American aboriginal populations screened. This allele is not present in U.S. whites but is present at a polymorphic frequency in U.S. and Nigerian blacks.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1989

Antilymphocytic antibodies and marrow transplantation. IX. T-cell depletion in marrow donors with C1q high and low affinity antibodies for suppression of GVHD in fully mismatched mice.

Rat monoclonal antibodies (mAbs) of the same specificity (anti-Thy-1) but different immunoglobulin (Ig) subclass were investigated for their effect on suppression of graft-versus-host disease (GVHD) by depleting the marrow donors of T cells in vivo. Transplantation to homozygous, fully mismatched mice of spleen and bone marrow cells from unthymectomized mice injected with the mAbs revealed that two rat anti-Thy-1 mAbs with high affinity for C1q (IgG2b) suppressed and prevented acute and chronic mortality of GVHD. In contrast, rat mAbs with low affinity for C1q (IgM, IgG2c) barely delayed acute mortality. This correlated with findings on the degree of splenic T-cell depletion in donor mice with the IgG2b mAb, able to deplete 97%, and the IgG2c and IgM mAbs, only 83% and 75% of T cells, respectively. An effect akin to the one achieved with IgG2b was seen, however, when donor mice were thymectomized and then treated with three injections of IgG2c isotype. The rat IgM mAb was not immunosuppressive even under such conditions. Immunocytochemical and immunohistochemical examination of the donor lymph nodes after single injection of either mAb showed that only 84% of T cells were eliminated, and in contrast to the spleen, none of the tested antibodies could deplete T cells further. The thymus did not appear depleted at all, although the cortical thymocytes were coated with either of the injected mAbs.

Animals↗
PubMed1989

Zidovudine-induced fever.

Zidovudine (3'-azido-3'deoxythymidine, AZT, Retrovir) is the first antiretroviral drug to demonstrate clinical efficacy for symptomatic human immunodeficiency virus infection. In a large, placebo-controlled trial, nausea and hematologic toxicity, but not fever, occurred more frequently in zidovudine- than in placebo-treated patients. However, in an open label study, fever severe enough to halt zidovudine administration occurred in 10% of 70 acquired immune deficiency syndrome (AIDS) patients receiving the drug. We now describe three AIDS patients with severe zidovudine-induced fever in whom other causes of fever were excluded. Zidovudine-induced fever was confirmed in each case by drug rechallenge. Using an enzyme immunoassay, we detected IgM antibodies directed against a zidovudine-serum protein conformational determinant in one of these three patients. Neither IgG nor IgM anti-zidovudine antibodies were present in sera from the other two patients with zidovudine fever, from four AIDS patients who discontinued zidovudine for reasons other than fever, or from five AIDS patients who never received zidovudine. Zidovudine may cause fever as a severe adverse effect in patients with AIDS. Either type III or type IV hypersensitivity may mediate this reaction.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Absence of induction of IL-1 production in human monocytes by complement fragments.

The ability of C fragments to induce IL-1 production in human monocytes was examined by using various approaches to carefully exclude the role of contaminating endotoxin. The presence of IL-1 activity in monocyte supernatants and lysates was assayed by the augmentation of PHA-induced proliferation of murine thymocytes. SRBC were opsonized with IgM rabbit antibodies and various human C components to prepare EAC reagents that contained less than 25 pg LPS/ml of EAC at 5 x 10(8) cells/ml. EAC1q, EAC4b, EAC4b2aoxy, EAC4b2aoxy C3b, EAC4b2aoxyC3bi, and EAC4b2aoxyC3d all failed to induce IL-1 production when incubated at 10- to 100-fold excess with adherent human monocytes. Similarly, LPS-free purified C3a, C5a, and C5a des Arg all showed no IL-1-inducing activities at concentrations up to 25 micrograms/ml. However, the same C5a preparations were active on human monocytes in the induction of chemotaxis, and C3a and C5a both induced skin-blueing in guinea pigs. Fragment Ba and Bb preparations purified by gel filtration chromatography contained approximately 100 pg LPS/micrograms Ba or Bb. These Ba and Bb preparations at 10 and 50 micrograms/ml, respectively, induced IL-1 production in the presence of 5 micrograms/ml polymyxin B (PMB). However, Ba and Bb preparations purified by affinity chromatography and HPLC contained lower levels of endotoxin contamination and displayed IL-1-inducing activities at Ba and Bb concentrations of 50 and 100 micrograms/ml, respectively, that were almost completely inhibited by PMB. To explore further the role of contaminating endotoxin, a Bb preparation was adsorbed with PMB-4B in the presence of a dialyzable detergent to remove LPS bound to the Bb. This LPS-free Bb preparation failed to induce IL-1 production while maintaining intact enzymatic activities. These results indicate that various solid phase or soluble C fragments, including C3b, iC3b, C3d, C3a, C5a, Ba or Bb do not induce IL-1 production in human monocytes in the absence of contaminating endotoxin.

Antigen-Antibody Complex↗
PubMedDate not supplied

[Velocity of nerve conduction in children and adolescents with type I diabetes mellitus: clinical, metabolic and immunologic correlations].

Clinical, metabolic, neurophysiologic and immunological data were obtained in a group of 50 patients with type I diabetes mellitus Results were compared with those obtained in 30 healthy subjects of comparable age. M.N.C. (median nerve conduction) velocities and sensitive latency were observed to be significant lower in the diabetic patients rather than in the controls. These abnormalities were correlated with the duration of diabetes rather than with the glucose control. The positivity for circulating immune complexes was found to be associated with a significant reduction of median sensory nerve conduction velocity. There results suggest that in addition to metabolic, genetic, vascular and hormonal abnormalities also immunologic factors may play a role in the pathogenesis of diabetic neuropathy.

Adolescent↗
PubMed1989

Pathogenesis of naturally acquired bovine respiratory syncytial virus infection in calves: evidence for the involvement of complement and mast cell mediators.

Indicators of immune-mediated disease were studied in calves with severe natural bovine respiratory syncytial virus infection. Although antigen and antibody were detected concurrently in most calves, immune complexes were not detected by use of immunofluorescence, ELISA, and binding of the 1q component of complement. Complement component C3, however, was observed by immunofluorescence in the cranioventral, virus-infected portion of the lungs of 19 of 25 calves. Reductions in the amount of histamine and in the numbers of mast cells and mast cell granules in the virus-positive cranioventral and virus-negative caudodorsal portions of the lungs, indicated activation of mast cells and liberation of their granule contents. On the basis of these and previous findings, a model for the pathogenesis of bovine respiratory syncytial virus-induced disease was proposed.

Animals↗
PubMedDate not supplied

[Distribution of aromatic amino acid residues according to the character of their microenvironment and the dynamics of the conformational properties of the protein molecule C1q].

The distribution of aromatic amino acid residues in the Clq molecule according to their microenvironment was studied by the methods of difference thermal and solvent perturbation spectroscopy, fluorescence and chemical modification. Out of the three tryptophan residues located in the globular part of A- chain one residue is completely exposed on the surface, while other two are only partially exposed to a solvent. Chemical modification of tryptophanyls significantly affects the hemolytic activity of Clq, that may evidence for the formation of immunoglobulin-binding sites with participation of A- chains as well as for the location of, at least, one of the three tryptophan residues in A- chain close to the immunoglobulin-binding site or even participation in the formation of the latter. The average rotation relaxation time of tryptophanyls estimated from the data on fluorescence is 210 +/- 10 ns. It specifies mobility of the globular and collagen parts of the molecule.

Amino Acids↗
PubMedDate not supplied

Use of high-dose intravenous immunoglobulin in systemic lupus erythematosus: report of three cases.

Three patients with life-threatening manifestations of systemic lupus erythematosus (SLE), unresponsive to conventional high-dose corticosteroid and/or immunosuppressive therapy were treated with intravenous polyspecific IgG (IVIG). Following IVIG infusion, lupus encephalitis in the first patient quickly resolved and the impressive improvement of the clinical status was associated with a transient increase in C1q-binding activity. The daily infusion of IgG had to be suspended after three days in the second patient with encephalitis and nephritis, because the renal function rapidly deteriorated; subsequently, six plasma exchanges led to an almost complete recovery. Finally, leukocyte and platelet counts increased and remained within normal range following IgG therapy in the third patient having SLE-associated leuko- and thrombocytopenia. In all three patients a decrease in anti-DNA antibody levels and an increase in total complement hemolytic activity were detected after therapy.

Adolescent↗
PubMed1978

Measurements of humoral immunity during treatment with levamisole in rheumatoid arthritis--a review.

Treatment with levamisole in patients with rheumatoid arthritis reduced significantly titers of rheumatoid factor and the amount of circulating immune complexes as determined by the Clq binding activity. It took between three and six months to observe a significant effect. Levamisole treatment had less effect on the amount of immunoglobulins in serum: the values were rarely abnormal before treatment and the changes were small, but reached statistical significance at six months. The effect on complement and complement components could not be evaluated as properly controlled studies were lacking.

Antigen-Antibody Complex↗
PubMed1985

[Cytotoxicity induced by the serum of patients with AIDS and at high risk of AIDS against cells infected with Epstein-Barr virus].

Serologic reactivity against EBV-infected lines was assayed in patients with AIDS (n = 4) or the AIDS related complex (AIDS-RC) (n = 46) residing in Argentina. Anti-VCA serology was comparable to that of controls. However sera from AIDS and AIDS-RC could induce antibody dependent cell mediated cytotoxicity (ADCC) to EBV-infected cell lines (P3HRIK and Raji). ADCC activity could be recovered in the high molecular weight fractions of AIDS and AIDS-RC sera. ADCC was observed in sera with high levels of PEG precipitable material (PEG-pp) but was unrelated to the presence of complement-fixing immune complexes (Clq-F) or to anti-VCA titers. Fc receptor (FcR) bridging between target cells FcR and effector cells FcR may play a role in the outcome of total ADCC.

AIDS-Related Complex↗
PubMed1988

The binding of native DNA to the collagen-like segment of Clq.

Our study was undertaken to determine if native DNA (dsDNA), which is known to bind to collagen, also binds to the collagen-like segment of Clq (CLS). Three methods were employed to demonstrate the binding of dsDNA to CLS: (1) Six human sera and a mouse monoclonal antibody to dsDNA were employed in an enzyme linked immunosorbent assay to detect CLS bound dsDNA. When applied to CLS bound dsDNA, sera with antibodies to dsDNA and monoclonal antibody to DNA yielded mean OD values of greater than or equal to 0.6, significantly higher than those values obtained from control experiments (mean OD less than or equal to 0.2, p less than or equal to 0.003). (2) In a solid phase immunoassay radiolabelled DNA (3H DNA) was exposed to increasing amounts of solid phase adherent CLS. The binding of 3H DNA to the solid phase was substantially greater (more than a 30-fold increase) when the solid phase had been precoated with CLS. (3) dsDNA binding to CLS was demonstrated further by incubating electrophoretically resolved CLS with dsDNA and localizing the bound dsDNA by ethidium bromide staining. Our results indicate the dsDNA binds to CLS. Since CLS is the binding site for Clr and then Clr2Cls2, molecules which bind to CLS, such as dsDNA, could be important factors affecting Cl activation.

Collagen↗
PubMed1985

A cell surface monoclonal antibody (H366) helps to discriminate human cytotoxic from suppressor T cells.

A study has been undertaken to differentiate T cytotoxic (Tc) and T suppressor (Ts) cell subsets using a monoclonal antibody termed H366 (mouse IgG2b) previously reported to phenotype natural killer and killer (NK/K) cells. Mononuclear cell suspensions from 14 normal subjects were depleted of H366+ cells by means of complement dependent cytotoxicity and the remaining cells were phenotyped with CD8 and CD4 monoclonal antibodies. The effects of depletion with H366 plus complement (C1) on the induction and activity of suppressor and cytotoxic T cells was also examined. The results indicate that H366 antibody recognizes in addition to NK/K cells, a population of Tc but not Ts or helper cells. Therefore, H366 antibody can be useful for obtaining Ts enriched lymphocyte subpopulations and this property may also be used for the enumeration of suppressor cells in the peripheral blood in disease states.

Antibodies, Monoclonal↗
PubMed1986

Alpha 2-plasmin inhibitor-plasmin complexes in synovial fluid.

The role of the fibrinolytic enzyme system in inflammatory joint disease has been addressed by several experimental approaches. In our study we examined synovial fluid (SF) in several different diseases for alpha 2-plasmin inhibitor-plasmin complexes by an enzyme linked immunosorbent assay (ELISA). These complexes are present in both rheumatoid and nonrheumatoid SF, with highest levels seen in septic arthritis. Thus the plasminogen system is intact in inflammatory SF, and plasmin may play a role in the local inflammatory process.

Antifibrinolytic Agents↗
PubMed1987

Effects of long-term seropositivity to human immunodeficiency virus in a cohort of homosexual men.

The long-term effects of HIV infection were evaluated by comparing data from two visits a mean of 18 months apart in groups of 148 persistently seropositive and 287 persistently seronegative homosexual men. At each visit, the seropositive men exhibited lower CD4 counts, CD4/CD8 ratios, hemoglobin concentrations and lymphocyte counts, and higher C1q binding, IgG and IgA levels. More important, the decline of the CD4/CD8 ratio and the rise of the C1q binding, IgG and IgA, progressed significantly in the seropositive group between visits. Seropositive men were at elevated risk of developing constitutional symptoms and generalized lymphadenopathy. An association was present between development of symptoms and inversion of the CD4/CD8 ratio. The 11 seropositive men who have progressed to AIDS had lower CD4 counts and CD4/CD8 ratios, and higher C1q binding, IgG and IgA, than 134 seropositive AIDS-free men a mean of 21.4 months prior to diagnosis. The AIDS group demonstrated greater decline between visits in the CD4 count, hemoglobin and white blood count (WBC) than the seropositive AIDS-free group. The present data document the long-term effects of HIV infection in a seropositive cohort and suggest the possibility of a subgroup particularly susceptible to the progressive effects of HIV that precede the development of the acquired immunodeficiency syndrome (AIDS).

Acquired Immunodeficiency Syndrome↗