Complement Fixation Inhibition Research Articles

Immune response to fungi in diabetic patients with invasive fungal rhinosinusitis.

This article aims to review the literature regarding the immune response to fungi in diabetic patients with invasive fungal rhinosinusitis. Systematic searches of Medline, EMBASE, and Cochrane Library databases were performed to include articles from 1988 to 2019 which assessed 'immune response to fungi in normal host', 'immune deficiency in diabetes mellitus', or 'immune response to fungi in diabetic patients'. Fungal cell wall activated pattern recognition receptors, resulting in recruitment of innate immune cells and an adaptive immune response. In diabetes mellitus, the expression of class I major histocompatibility complex was reduced. A hyperglycemic state decreased vascular dilation and the formation of neutrophil extracellular traps. The structure of complement was altered with consequent inhibition of complement fixation to bacteria. The balance between complement activation and restriction was broken. Hyperglycemia activated protein kinase C which inhibited neutrophil migration, decreased production of polymorphonuclear cells, decreased chemotaxis and decreased phagocytic activity. Germination and filamentous growth of the fungus within a diabetic host caused angioinvasion, vascular thrombosis and necrosis. Patients with diabetic ketoacidosis had elevated levels of serum iron which regulated endothelial cell damage. Iron and the overexpression of glucose-induced glucose-regulated protein 78 enhanced the susceptibility of endothelial cells to fungi and induced fungal invasion. In summary, associations among the immunopathology of diabetes, the pathophysiology of fungal infections, and the therapeutic outcomes must be considered in clinical practice. In diabetic patients, both the humoral and cellular immune responses of innate and adaptive immune systems were defective. Treatments should aim for the immune function restoration.

Immunological and biochemical characterisation of 7ap, a short protein translated from an alternative frame of ORF7 of PRRSV.

Sequence analysis revealed a short alternative open reading frame (ORF) named ORF7a within the nucleocapsid gene of genetically divergent porcine reproductive and respiratory syndrome virus (PRRSV) genomes. Alignment of the corresponding protein sequences (named 7ap) revealed substantial heterogeneity among 7aps of different genotypes, though all of them are predicted to be positively charged. Green fluorescent protein and FLAG fusion constructs of ORF7a of the HU-14432/2011 PRRSV demonstrated that 7ap is expressed. 7ap of HU- 14432/2011 (Hu7ap) was synthesised chemically, and ELISA experiments revealed that Hu7ap binds strongly to mammalian IgGs. Protein-protein gel retardation assays and complement fixation inhibition suggest that 7aps bind to the CH2 domain of the IgG(Fc) fragment. Cellular localisation and immunological characteristics of PRRSV 7ap may indicate multiple functions including nuclear and cytoplasmic over-tuning of normal cellular processes and immunosuppression.

The association between Mi‐2 antibodies and dermatomyositis

Antibodies to Mi, an antigen in calf thymus extract, have been demonstrated by complement fixation inhibition in polymyositis (PM) and dermatomyositis (DM) sera but not in the sera of individuals without myositis. The original Mi reference serum defined 2 precipitating antibodies, using immunodiffusion (ID). Anti-Mi-1 was not active in complement fixation. We have now studied in further detail anti-Mi-2, which appears to be the antibody in Mi serum that fixes complement. Mi-2 antigen was purified by immuno-affinity chromatography. An enzyme-linked immunosorbent assay (ELISA) to measure Mi-2 antibody, using this antigen, was used to test the sera of 139 myositis patients: 52 had DM and 87 had PM. Control sera from 35 normal subjects and 93 patients with other connective tissue diseases were also tested. Only 13 sera were considered definitely positive for anti-Mi-2. All were from patients who had myositis, 11 of whom had DM. Only DM sera had anti-Mi-2 by ID, and all sera with anti-Mi-2 by ID were positive by ELISA. A number of other sera, including many from patients with other connective tissue diseases and 2 from normal subjects (all without precipitating antibodies) had lower elevations which were of uncertain significance. Detection of anti-Mi-2 by ID as well as by ELISA was significantly more frequent in DM than in PM. Anti-Mi-2 appears to be closely linked to DM, and is the first specific serologic marker for this form of myositis.

Immunochemical studies of turnip yellow mosaic virus III. Localization of two viral epitopes in residues 57–64 and 183–189 of the coat protein

The antigenic activity of the C-terminal region of the coat protein of turnip yellow mosaic virus was investigated with two synthetic peptides corresponding to residues 183–189 and 187–189. The inhibitory activity of these peptides was measured by complement fixation, ELISA and RIA, using either antibodies directed to the depolymerized viral subunits or antibodies to the capsid. Although the activity of the peptides varied markedly in the different assays, the results clearly demonstrated that the C-terminal residues 183–189 correspond to an antigenic determinant present at the outer surface of the assembled capsid. Another synthetic peptide corresponding to residues 57–64 of the coat protein was also prepared and found by inhibition of complement fixation to correspond to an antigenic determinant of the virus. These results bring to three the number of antigenic determinants of the virus particle that have been located.

Immunochemical studies of tobacco mosaic virus—V. Localization of four epitopes in the protein subunit by inhibition tests with synthetic peptides and cleavage peptides from three strains

Two antigenic determinants have been located in the vicinity of residues 1–10 and 34–39 of the coat protein of tobacco mosaic virus by means of ELISA and complement fixation inhibition experiments with synthetic peptides. The determinant present in residues 1–10 is also expressed at the outer surface of the subunits when they are assembled into virions. Two other determinants expressed in the dissociated protein subunit have been located in the vicinity of residues 55–61 and 80–90 by means of inhibition tests with tryptic peptides. These results bring to seven the number of antigenic determinants of the protein subunit that have been located.

Immunochemical detection of N6-methyladenine in DNA

Antibodies to N 6-methyladenosine were produced in rabbit by means of immunization with N 6-methyladenosine coupled to bovine serum albumin via periodate oxidation. Cross-reacting antibodies were removed by bovine serum albumin-Sepharose and appropriate nucleoside-human serum albumin absorbents. Nucleoside-specific antibodies were isolated by affinity chromatography on N 6-methyladenosine-human serum albumin-Sepharose. The specificity of the purified antibodies has been demonstrated by complement fixation inhibition analyses using nucleoside analogues as inhibitors. The homologous hapten was about 10 3 times more effective in inhibition than dAMP. Anti- N 6-methyladenosine was used to detect N 6-methyladenine in denatured DNAs from various sources by complement fixation. Practically no complement fixation has been found with DNAs containing no N 6-methyladenine, such as calf thymus, salmon sperm, Micrococcus radiodurans, Streptomyces chrysomallus and Streptomyces hygroscopicus, whereas a weak reactivity occurred in the case of Bacillus subtilis DNA and Sarcina maxima DNA. For DNA from Proteus mirabilis, Escherichia coli K-12, E. coli B, E. coli WF +, λ, T2 phages quantitative differences in the immunochemical reactivity were observed, which only partially correlate with the N 6-methyladenine content of the DNAs. Other factors, influencing the accessibility of N 6-methyladenine to the antibody-combining site have to be taken into consideration.

Nature of antigenic determinant of serovar-specific antigen of Leptospira interrogans serovar hebdomadis.

The nondialyzable delipidized serovar-specific main antigen (NDTM antigen) of Leptospira interrogans serovar hebdomadis strain Hebdomadis (a variant which can grow in a synthetic medium) showed a strong inhibition of the complement fixation between the serovar-specific main (TM) antigen of this strain and the homologous antiserum. The inhibitory effect of the NDTM antigen was completely lost by treating the antigen with proteolytic enzymes, and the fractions of TM antigen containing amino sugar, neutral sugars, and lipids did not show any inhibition of complement fixation, indicating that the antigenic determinant of this strain is related to proteins. NDTM antigen contained more hydrophilic amino acids than hydrophobic amino acids, whereas TM antigen contained more hydrophobic amino acids than hydrophilic amino acids. The amino acid compositions of NDTM antigens of hebdomadis strain Hebdomadis (variant) and kremastos strain Kyoto, which belonged to the same serogroup, were considerably similar. Difference was found in the amounts of methionine, arginine, lysine and glutamine acid.

Isolation of a soluble tumor-associated antigen from human melanoma.

Human melanoma-associated antigen was solubilized from fresh surgical specimens by 3 M KC1 extraction. The antigenicity of this extract was demonstrated by delayed cutaneous hypersensitivity responses and inhibition of complement fixation. Twenty-one of 33 melanoma patients had delayed cutaneous hypersensitivity responses to melanoma antigen, while only four of 28 reacted to autologous muscle. Although KC1 extracts did not fix complement directly, they reacted with antibody, thus inhibiting complement fixation by the autologous melanoma antigen extracted from tissue culture supernatants. The soluble antigenic moiety was then purified by fractionation on a G-150 Sephedex column and polyacrylamide gels, and the antigenic activity was monitored by delayed cutaneous hypersensitivity responses in melanoma patients. A 20-fold purification was achieved. Solubilization of tumor antigens with 3 M KC1 provides tumor-associated antigen of high activity which is amenable to further biochemical purification.

Immunological comparison of basic encephalitogen and histone F2A1.

The extent of immunological cross-reaction between basic encephalitogen and histone F2A1 on both the humoral antibody level and on the cellular level has been established. The extent of humoral cross-reaction was tested by direct complement fixation employing both anti-histone F2A1 and antisera to basic encephalitogen, by inhibition of complement fixation, by radioimmunoassay and by passive cutaneous anaphylaxis. The data obtained failed to reveal immunological cross-reaction at the cellular level was tested by the lymphocyte stimulation technique in rabbits and guinea pigs, by inhibition of lymphocyte stimulation and by delayed hypersensitivity skin reactions. A slight but significant cross-reaction between the two proteins on the cellular level was detected by inhibition of lymphocyte stimulation and by the delayed hypersensitivity test. It is concluded that the immunological studies provide limited evidence that the two proteins share antigenic determinants.

Microcomplement-fixation inhibition: a rapid and economical test to detect non-complement-fixing antibodies.

Complement-fixation inhibition test was adapted to the microtiter system. When cat and monkey non-complement-fixing antibody were used, the microtest was shown to be as sensitive as the conventional tube complement-fixation inhibition test.

Microcomplement-Fixation Inhibition: a Rapid and Economical Test to Detect Non-Complement-Fixing Antibodies

Complement-fixation inhibition test was adapted to the microtiter system. When cat and monkey non-complement-fixing antibody were used, the microtest was shown to be as sensitive as the conventional tube complement-fixation inhibition test.

On the immunological inter-relationships of the vertebrate esterases

1. 1. In order to assess the immunological inter-relationships of the vertebrate esterases, antisera were produced against several purified enzymes from the different esterolytic classifications, namely sheep liver carboxylesterase (carboxylic-ester hydrolase, EC 3.1.1.1.), horse serum cholinesterase (acylcholine acyl-hydrolase, EC 3.1.1.8), ox testis acetylesterase (acetic-ester hydrolase, EC 3.1.1.6) and ox serum arylesterase (acyl-ester hydrolase, EC 3.1.1.2). 2. 2. These antisera were tested for their interactions at the level of enzyme heterogeneity, by gel electrophoresis of a representative range of tissues before and after incubation with the sera, followed by observation of the alteration in the patterns of esterase heteromorphs consequent upon this treatment. 3. 3. From these results, it appears that a close immunological relationship exists between the multiple forms of each individual esterase type within a single species. In the case of the acetylesterases, this immunological relationship extends between the species as well. A close relationship was also observed between chicken liver carboxylesterase and horse serum cholinesterase, and to a lesser degree between these two latter enzymes and sheep liver carboxylesterase. 4. 4. In addition to the electrophoretic studies, complement fixation inhibition assays were carried out between each of the antisera and all the purified antigens. Also, micro-complement fixation assays between the antisera to the chicken liver carboxylesterase and horse serum cholinesterase were effected with all the antigens. These immunological tests with pure enzymes served to verify that a degree of relationship exists between the hose cholinesterase and the chicken carboxylesterase. 5. 5. The significance of these results has been discussed in relation to the phylogenetic variability of the esterases, the complex structural and genetic inter-relationships of these multiple enzyme forms, and the comparative situation in intensively studied isoenzyme systems.

Demonstration of Antibody in Cat Sera to Feline Oncornavirus by Complement-Fixation Inhibition<xref ref-type="fn" rid="FN1">2</xref>

Demonstration of Antibody in Cat Sera to Feline Oncornavirus by Complement-Fixation Inhibition<xref ref-type="fn" rid="FN1">2</xref>

The Complement-Fixation Reaction in Equine Infectious Anemia: Demonstration of Inhibition by IgG(T)

Abstract The role of non-complement-fixing anti-equine infectious anemia (EIA) antibody in the conversion of complement fixation (CF) tests from positive to negative in EIA-infected horses was investigated. Complement-fixation inhibition (CFI) tests demonstrated antibodies in sera that were CF negative. These antibodies would bind to antigen, but would not fix complement. The inhibiting antibodies were isolated and shown to be IgG(T) by immunoelectrophoresis and immunodiffusion against monospecific anti-IgG(T) antisera. Separation of immunoglobulins from affected horse sera by DEAE cellulose chromatography revealed 11 of 13 had complement-fixing IgG and non-complement-fixing IgG(T) antibodies present simultaneously regardless of the reactivity of whole sera. The reactivity of whole sera in CF and CFI tests evidently depended upon the relative concentration and perhaps affinity of the Ig classes. The predominant class fluctuated in serial sera from four of six persistently infected horses.

The presence of avian leukosis virus group-specific antibodies in chicken sera

Experiments designed to investigate by complement-fixation inhibition tests the group-specific antibody response to an injected dose of either subgroup A or subgroup B strains of avian leukosis virus (ALV) were carried out in chickens 2 1 2 , 6, and 23–25 weeks of age. Many 2 1 2 and 6-week-old birds responded with group-specific (gs) antibody whereas the antibody response of birds injected at 23–25 weeks was very poor. Birds congenitally infected with an ALV of subgroup A were immunologically tolerant to the gs antigen and did not respond with gs antibody whether the challenge virus was subgroup A or B. A comparison between neutralizing and gs antibody activity in 70 immune chicken sera showed: (1) the greatest number of sera containing gs antibody were those with titers of neutralizing antibody > 1 1000 , (2) all gs-positive sera had titers of neutralizing antibody > 1 200 , and (3) only 56% of the sera with high neutralizing activity contained gs antibody. Fractionation of two chicken sera containing gs antibody was carried out to separate the IgM and IgG fractions. The gs antibody activity, as well as most of the neutralizing activity, was found in the IgG fractions.

The Chemical Nature of <i>Shigella flexneri </i>Group Antigen Factor 6

The specific polysaccharides isolated from <i>Shigella flexneri </i>serotypes lb, 3c, 4b and mutant Z were found to be O-acetylated. One oligosaccharide unit of each examined polysaccharide contained one O-acetyl group. By means of complement fixation inhibition test the polysaccharides were studied before and after deacetylation. They were shown to be strong inhibitors of the group 6 system, but the removal of O-acetyl groups resulted in the complete loss of their group 6 specificity. The process of deacetylation destroys also type III specificity, but hardly affects type I and type IV systems. The polysaccharides improved their inhibitory power in the group 3, 4 system after deacetylation.

Effect of hexons on the quantitation of adenovirus non-specific hemagglutination inhibitor and its titration by complement fixation inhibition. Brief report.

Effect of hexons on the quantitation of adenovirus non-specific hemagglutination inhibitor and its titration by complement fixation inhibition. Brief report.

Immunological Determinants of Avian Sarcoma Viruses: Presence of Group-Specific Antibodies in Fowl Sera Demonstrated by Complement-Fixation Inhibition Test

A complement-fixation inhibition test revealed antibodies in the sera of fowls immunized with Rous sarcoma virus (RSV). These antibodies were specific for antigen preparations of representative members of the avian leukosis complex and cross reacted with all antigens tested with the characteristics of group-specific antibodies. The antigens studied included: 1) chick-embryo tissue-cultured cells infected with the following strains of RSV—Bryan high-titer (BH-RSV), Schmidt-Ruppin (SR-RSV), Harris (H-RSV), and a strain of avian lymphomatosis RPL12; 2) tumors induced in chickens, turkeys, and Japanese quail with BH-RSV and SR-RSV; and 3) hamster tumors induced by SR-RSV. The RSV group-specific antibodies in fowl sera had no neutralizing activity.

Antigenic structure of human gonadotropins: contribution of carbohydrate moiety to the antigenic structure of pituitary follicle-stimulating hormone.

Precipitating, complement-fixing and neutralizing antibody was produced in rabbits by immunization with a partially purified human pituitary FSH preparation. Apparent serological specificity of this antiserum was increased after absorption with human serum and HCG. Attempts were made to examine immunologic carbohydrate determinant groups of human pituitary FSH by complement-fixation inhibition reactions between the absorbed antiserum and homogeneous human pituitary FSH preparations, using mono- and disaccharides, and by treatment of the hormone preparations with several carbohydrate-hydrolyzing enzymes. Of the saccharides tested, galactose, β-methyl- D-galactopyranoside lactose and melibiose were active in the inhibition test, and the disaccharides were more effective than the monosaccharides on an equimolar basis. Ovarian weight augmentation activity of FSH was completely abolished, but its complement-fixing property was not affected after treatment with neuraminidase. Both biologic and immunologic prope...

Specificity and reactivity of cytoplasmic and nucleolar antibody in SLE sera.

The serum of 2 of 31 patients with SLE was found to contain an antibody to a previously unrecognized RNA-containing antigen found in human mononuclear cell cytoplasm and nucleolus. When tissue fixed, this antibody proved capable of fixing the patient's own rheumatoid factor and human complement components. No recognizable inhibition of complement fixation by rheumatoid factor could be demonstrated by the fluorescent antibody technic.