Weak autoantibody reactions to antigens other than sperm after vasectomy.
Autoantibody activity against various antigens was measured by indirect immunofluorescence in 97 men about to undergo vasectomy and 170 men who had undergone the operation up to six years earlier. There was a significantly higher prevalence of weakly positive autoantibody reactions among those who had undergone vasectomy. There was, however, no evidence that vasectomy could induce stronger autoantibody reactions such as those associated with autoimmune disease. (+info)
Lymphocyte proliferation inhibitory factor (PIF) in alcoholic liver disease.
Lymphocyte proliferation inhibitory factor (PIF) was determined in the supernatants of PHA-stimulated lymphocytes from patients with alcoholic liver disease. PIF was assayed by determining inhibition of DNA synthesis in WI-38 human lung fibroblasts. A two-fold greater inhibition in thymidine incorporation into DNA by lung fibroblasts was observed in supernatants of PHA stimulated lymphocytes from patients with alcoholic hepatitis or active Laennec's cirrhosis as compared with that found in control subjects or patients with fatty liver. It is suggested that decreased liver cell regeneration seen in some patients with alcoholic hepatitis may be due to increased elaboration of PIF. (+info)
Features of the immune response to DNA in mice. I. Genetic control.
The genetic control of the immune response to DNA was studied in various strains of mice F1 hybrids and corresponding back-crosses immunized with single stranded DNA complexed to methylated bovine serum albumin. Anti-DNA antibody response was measured by radioimmuno-logical technique. High responder, low responder, and intermediate responder strains were found and the ability to respond to DNA was characterized as a dominant genetic trait which is not linked to the major locus of histocompatibility. Studies in back-crosses suggested that this immune response is under multigenic control. High responder mice produce both anti-double stranded DNA and anti-single stranded DNA 7S and 19S antibodies, while low responder mice produce mainly anti-single stranded DNA 19S antibodies. (+info)
Highly sensitive quantitation of methamphetamine by time-resolved fluoroimmunoassay using a new europium chelate as a label.
A simple and highly sensitive time-resolved fluoroimmunoassay of methamphetamine (MA) using a new fluorescent europium chelate (BHHCT-Eu3+) as a label is described. Two variations of competitive immunoassay were attempted. In the first (one-step) assay, microtiter plates coated with anti-MA were used, and the new label was bound to a conjugate of bovine serum albumin and N-(4-aminobutyl)-MA (MA-BSA). In the second (two-step) assay, instead of the labeled MA-BSA, biotinylated MA-BSA and BHHCT-Eu3+-labeled streptavidin-BSA were used. The lowest measurable concentrations of MA for the one-step and the two-step methods were 1 ng/mL (25 pg/assay) and 1 pg/mL (25 fg/assay), respectively. These were 10 to 1000 times superior to the detection limits of MA in any other immunoassay. Intra-assay coefficient of variation was approximately 2-8% at eight different concentrations (n = 4). Analysis of 34 urine samples with the new method and conventional gas chromatography showed a good correlation (r = 0.954). The high detectability of the present assay also enabled segmental hair analysis with a few centimeters of a hair. (+info)
Variable domain-linked oligosaccharides of a human monoclonal IgG: structure and influence on antigen binding.
The variable-domain-attached oligosaccharide side chains of a human IgG produced by a human-human-mouse heterohybridoma were analysed. In addition to the conserved N-glycosylation site at Asn-297, an N-glycosylation consensus sequence (Asn-Asn-Ser) is located at position 75 in the variable region of its heavy chain. The antibody was cleaved into its antigen-binding (Fab) and crystallizing fragments. The oligosaccharides of the Fab fragment were released by digestion with various endo- and exoglycosidases and analysed by anion-exchange chromatography and fluorophore-assisted carbohydrate electrophoresis. The predominant components were disialyl- bi-antennary and tetra-sialyl tetra-antennary complex carbohydrates. Of note is the presence in this human IgG of oligosaccharides containing N-glycolylneuraminic acid and N-acetylneuraminic acid in the ratio of 94:6. Furthermore, we determined N-acetylgalactosamine in the Fab fragment of this antibody, suggesting the presence of O-linked carbohydrates. A three-dimensional structure of the glycosylated variable (Fv) fragment was suggested using computer-assisted modelling. In addition, the influence of the Fv-associated oligosaccharides of the CBGA1 antibody on antigen binding was tested in several ELISA systems. Deglycosylation resulted in a decreased antigen-binding activity. (+info)
PDGF (alpha)-receptor is unresponsive to PDGF-AA in aortic smooth muscle cells from the NG2 knockout mouse.
A line of null mice has been produced which fails to express the transmembrane chondroitin sulfate proteoglycan NG2. Homozygous NG2 null mice do not exhibit gross phenotypic differences from wild-type mice, suggesting that detailed analyses are required to detect subtle alterations caused by the absence of NG2. Accordingly, dissociated cultures of aortic smooth muscle cells from null mice were compared to parallel cultures from wild-type mice for their ability to proliferate and migrate in response to specific growth factors. Both null and wild-type smooth muscle cells exhibited identical abilities to proliferate and migrate in response to PDGF-BB. In contrast, only the wild-type cells responded to PDGF-AA in both types of assays. NG2 null cells failed to proliferate or migrate in response to PDGF-AA, implying a defect in the signaling cascade normally initiated by activation of the PDGF (alpha)-receptor. In agreement with this idea, activation of the extracellular signal-regulated kinase (ERK) in response to PDGF-AA treatment occured only in wild-type cells. Failure to observe autophosphorylation of the PDGF (alpha)-receptor in PDGF-AA-treated null cells indicates that the absence of NG2 causes a defect in signal transduction at the level of (alpha)-receptor activation. (+info)
Ma1, a novel neuron- and testis-specific protein, is recognized by the serum of patients with paraneoplastic neurological disorders.
The identification of antineuronal antibodies has facilitated the diagnosis of paraneoplastic neurological disorders and the early detection of the associated tumours. It has also led to the cloning of possibly important neuron-specific proteins. In this study we wanted to identify novel antineuronal antibodies in the sera of patients with paraneoplastic neurological disorders and to clone the corresponding antigens. Serological studies of 1705 sera from patients with suspected paraneoplastic neurological disorders resulted in the identification of four patients with antibodies that reacted with 37 and 40 kDa neuronal proteins (anti-Ma antibodies). Three patients had brainstem and cerebellar dysfunction, and one had dysphagia and motor weakness. Autopsy of two patients showed loss of Purkinje cells, Bergmann gliosis and deep cerebellar white matter inflammatory infiltrates. Extensive neuronal degeneration, gliosis and infiltrates mainly composed of CD8+ T cells were also found in the brainstem of one patient. In normal human and rat tissues, the anti-Ma antibodies reacted exclusively with neurons and with testicular germ cells; the reaction was mainly with subnuclear elements (including the nucleoli) and to a lesser degree the cytoplasm. Anti-Ma antibodies also reacted with the cancers (breast, colon and parotid) available from three anti-Ma patients, but not with 66 other tumours of varying histological types. Preincubation of tissues with any of the anti-Ma sera abrogated the reactivity of the other anti-Ma immunoglobulins. Probing of a human complementary DNA library with anti-Ma serum resulted in the cloning of a gene that encodes a novel 37 kDa protein (Mal). Recombinant Mal was specifically recognized by the four anti-Ma sera but not by 337 control sera, including those from 52 normal individuals, 179 cancer patients without paraneoplastic neurological symptoms, 96 patients with paraneoplastic syndromes and 10 patients with non-cancer-related neurological disorders. The expression of Mal mRNA is highly restricted to the brain and testis. Subsequent analysis suggested that Mal is likely to be a phosphoprotein. Our study demonstrates that some patients with paraneoplastic neurological disorders develop antibodies against Mal, a new member of an expanding family of 'brain/testis' proteins. (+info)
Predominant VH genes expressed in innate antibodies are associated with distinctive antigen-binding sites.
Antibodies to phosphatidylcholine (PtC), a common constituent of mammalian and bacterial cell membranes, represent a large proportion of the natural antibody repertoire in mice. Previous studies of several mouse strains (e.g., C57BL/6) have shown that anti-PtC antibodies are mainly encoded by the VH11 and VH12 immunoglobulin heavy chain variable region gene families. We show here, however, that VH11 and VH12 encode only a small proportion of the anti-PtC antibodies in BALB/c mice. Instead, VHQ52-encoded antibodies predominate in this strain. In addition, two-thirds of the cells expressing VHQ52 family genes use a single gene (which, interestingly, has been previously shown to predominate in the anti-oxazolone response). We also show here that in anti-PtC antibodies from all strains, the distinctive antigen-binding sites associated with VHQ52 differ substantially from those associated with VH11 and VH12. That is, VHQ52-containing transcripts preferentially use the joining region JH4 rather than JH1 and exhibit more diverse complementarity-determining region 3 (CDR3) junctions with more N-region nucleotide additions at the gene segment junctions. Thus, the VH gene family that predominates in the anti-PtC repertoire differs among mouse strains, whereas the distinctive VHDJH rearrangements (CDR3, JH) associated with each VH gene family are similar in all strains. We discuss these findings in the context of a recent hypothesis suggesting that CDR3 structure, independent of VH framework, is sufficient to define the specificity of an antibody. (+info)