Scarcity or absence of humoral immune responses in the plasma and cervicovaginal lavage fluids of heavily HIV-1-exposed but persistently seronegative women.

To address an existing controversy concerning the presence of HIV-1-specific antibodies of the IgA isotype in the female genital tract secretions of highly-exposed but persistently seronegative (HEPSN) women, 41 samples of plasma and cervicovaginal lavage (CVL) fluid were distributed to six laboratories for their blinded evaluation using ELISA with 10 different HIV-1 antigens, chemiluminescence-enhanced Western blots (ECL-WB), and virus neutralization. HIV-specific IgG or IgA antibodies in plasma samples from HEPSN women were absent or detectable only at low levels. In CVL, 11/41 samples displayed low levels of reactivity in ELISA against certain antigens.

Identification and characterization of CMP-NeuAc:GalNAc-IgA1 alpha2,6-sialyltransferase in IgA1-producing cells.

Glycosylation defects occur in several human diseases. In IgA nephropathy, IgA1 contains O-glycans that are galactose-deficient and consist mostly of core 1 alpha2,6 sialylated N-acetylgalactosamine, a configuration suspected to prevent beta1,3 galactosylation. We confirmed the same aberrancy in IgA1 secreted by the human DAKIKI B cell line.

Reactivities of N-acetylgalactosamine-specific lectins with human IgA1 proteins.

Lectins are proteins with specificity of binding to certain monosaccharides or oligosaccharides. They can detect abnormal glycosylation patterns on immunoglobulins in patients with various chronic inflammatory diseases, including rheumatoid arthritis and IgA nephropathy (IgAN). However, lectins exhibit binding heterogeneity, depending on their source and methods of isolation.

IgA-containing immune complexes in the urine of IgA nephropathy patients.

Background: Sera of IgA nephropathy (IgAN) patients contain high levels of circulating immune complexes composed of IgA1 molecules with aberrantly glycosylated hinge-region O-linked oligosaccharides and IgG or IgA1 antibodies with anti-glycan or anti-hinge-region peptide specificities. Due to damaged sieving properties of the glomerular capillary wall in IgAN, these immune complexes may appear in the urine.

Methods: We collected urine samples from 29 patients with biopsy-proven IgAN (Group I), 27 proteinuric patients with non-IgA nephropathies (Group II) and 28 healthy volunteers (Group III).

Human male genital tract secretions: both mucosal and systemic immune compartments contribute to the humoral immunity.

In contrast to numerous studies of female genital tract secretions, the molecular properties of Abs and the magnitude of humoral responses in human male genital tract secretions to naturally occurring Ags and to mucosal and systemic immunizations have not been extensively investigated. Therefore, seminal plasma (SP) collected from healthy individuals was analyzed with respect to Ig levels, their isotypes, molecular forms of IgA, and for the presence of Abs to naturally occurring Ags, or induced by systemic or mucosal immunizations with viral and bacterial vaccines. The results indicated that in SP, IgG and not IgA, is the dominant Ig isotype, and that IgM is present at low levels.

Increased levels of galactose-deficient IgG in sera of HIV-1-infected individuals.

Background: The IgG from sera of patients with chronic inflammatory diseases of autoimmune character or some chronic microbial infections is frequently deficient in galactose on N-linked glycans. However, this phenomenon has not been investigated at length in human viral infections.

Objectives: To evaluate the glycosylation of serum IgG in HIV-1-positive patients.

Determination of aberrant O-glycosylation in the IgA1 hinge region by electron capture dissociation fourier transform-ion cyclotron resonance mass spectrometry.

In a number of human diseases of chronic inflammatory or autoimmune character, immunoglobulin molecules display aberrant glycosylation patterns of N- or O-linked glycans. In IgA nephropathy, IgA1 molecules with incompletely galactosylated O-linked glycans in the hinge region (HR) are present in mesangial immunodeposits and in circulating immune complexes. It is not known whether the Gal deficiency in IgA1 proteins occurs randomly or preferentially at specific sites.

Paucity of antigen-specific IgA responses in sera and external secretions of HIV-type 1-infected individuals.

This study was undertaken to resolve existing controversies with respect to the detection of IgA HIV-1-specific mucosal antibodies in infected individuals. External secretions, including tears, nasal, rectal, and vaginal washes, saliva, semen, urine, and sera were obtained from 50 HIV-1-infected individuals and 20 controls using collection procedures that minimize the irritation of mucosal surfaces. Levels of total and antigen (gp120 and gp160)-specific antibodies of the IgG and IgA isotypes were measured by assays that proved reliable in a large multicenter study: quantitative ELISA and chemiluminescence-enhanced Western blot analyses.

Heterogeneity of O-glycosylation in the hinge region of human IgA1.

Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry was applied to studies of the molecular heterogeneity of desialylated human IgA1 hinge region glycopeptides released with two IgA1 proteases. Typically, the hinge region of an alpha1 chain contains three to five O-linked glycan chains. Variants of the hinge region peptides released from IgA1(Kni) myeloma protein carrying 0, 1, 2, or 3 GalNAc residues were observed in the mass spectra as well as the nonglycosylated peptide.

False positivity of enzyme-linked immunosorbent assay for measurement of secretory IgA antibodies directed at HIV type 1 antigens.

We have determined that polymeric IgA in saliva of HIV-1-uninfected individuals binds in varying degrees to components of culture supernatants containing HIV-1 recombinant proteins when ELISA is used for the determination. This finding did not extend to salivary IgG antibodies. Further, such problems were not encountered in Western blot.

Text Learning Using Scientific Diagrams: Implications for Classroom Use.

In two experiments, eighth-graders viewed ecologically valid diagrams and then read a text containing multiple feature-to-fact associations or studied the same materials in reverse order. Using the Kulhavy and Stock model of text learning using organized spatial displays, it was predicted that those students viewing the diagram prior to reading the text would recall more facts and features than subjects viewing the material in the reverse order. These predictions were well supported.

Carbohydrate heterogeneity of human myeloma proteins of the IgA1 and IgA2 subclasses.

Comparative studies of the N-linked carbohydrate chains of human myeloma proteins of the IgA1 and IgA2 subclasses were performed. The N-linked carbohydrate chains were released by hydrazinolysis from the polypeptide backbone, converted to radioactive oligosaccharides by sodium borotritide reduction after N-acetylation and separated into one neutral and two acidic fractions by paper electrophoresis. The acidic oligosaccharides were completely converted to neutral oligosaccharides by sialidase treatment, indicating that they were sialyl derivatives.

Personality characteristics and duration of ATA Taekwondo training.

Students in ATA Taekwondo schools were administered the 16 Personality Factor Questionnaire. The students were divided into two groups of 15 persons each based on 0-1.4 yr.

Interactions of galactosyltransferase with serum and secretory immunoglobulins and their component chains.

Assay of the activity of beta-1,4-galactosyltransferase (beta-1,4-GT) revealed that in addition to serum, milk, colostrum, amniotic and cerebrospinal fluids and malignant effusions, this enzyme is present also in tears and saliva. Molecular-sieve chromatography of human colostral whey and serum and subsequent assay of beta-1,4-GT activity have shown that beta-1,4-GT was present as a free enzyme (55 kDa) and associated with components of larger molar mass. The elution pattern did not change when the chromatography was carried out in a buffer devoid of, or enriched with, Mn2+, a cofactor of beta-1,4-GT activity.

Interactions of cell-surface galactosyltransferase with immunoglobulins.

Detection of the activity of beta-1,4-galactosyltransferase (beta-1,4-GT) in suspensions of viable mouse hepatocytes, the human hepatoma cell line Hep G2, the human colonic adenocarcinoma cell line HT-29, the monocyte-like cell line U937, and human splenic B and T lymphocytes suggested the presence of beta-1,4-GT, in an enzymatically active form, on plasma membranes. The presence of beta-1,4-GT on cell surfaces was also indicated from the effect of trypsinization of live cells, which significantly reduced cell surface beta-1,4-GT activity, but did not affect the activity associated with cytoplasmic membranes. Furthermore, the presence of beta-1,4-GT on the cell surface was demonstrated by indirect immunofluorescence staining of cells with anti-beta-1,4-GT antibody.

Cytokine-induced immunoglobulin production in primary IgA nephropathy.

Increased IgA synthesis probably plays a role in the pathogenesis of IgA nephropathy (IgAN). We investigated whether an increased sensitivity to the effect of various growth factor combinations leads to increased immunoglobulin synthesis by peripheral blood mononuclear cells (PBMC) from IgAN patients, in comparison to healthy controls. Although none of the growth factors studied (pokeweed mitogen [PWM], interleukin [IL]-2, IL-6, transforming growth factor-beta [TGF-beta], and combinations) led to greater IgA synthesis in IgAN patients than in controls, the IgA subclass ratio was shifted in favor of IgA1.

Transforming growth factor-beta inhibits the production of IgG, IgM, and IgA in human lymphocyte cultures.

Transforming growth factor beta (TGF beta) has potent immunoregulatory effects acting on both T and B cells. It strongly inhibits secretion of IgG and IgM in human and murine B cell cultures, but has been shown to have an enhancing effect on IgA production in the mouse. We have studied the effect of TGF beta on the production of IgA in human lymphocyte cultures.

Measuring cognitive processes in patients with Parkinson's disease.

Parkinsonians and control subjects completed a series of cognitive tasks which measured primed semantic retrieval, conceptual organization, and conjoint retention. Direct measures of cognitive processing failed to yield the wide range intellectual deficit patterns that have been found with parkinsonians.

Response feedback, certitude and learning from text.

Based upon the premise that persons modify their study behaviours in order to maintain their certainty of responding correctly, a study was conducted with 40 undergraduate volunteers examining the effects of different presentation rates and feedback context on response confidence and correct responding. Significant effects in the anticipated direction were found for presentation rate but not for the context of feedback.

Degradation of IgA proteins by Pseudomonas aeruginosa elastase.

Human colostral IgA and myeloma proteins of both IgA1 and IgA2 subclasses were susceptible to cleavage by Pseudomonas aeruginosa elastase. Detailed analysis of the cleavage products of IgA myeloma proteins revealed complete degradation of Fab with no evidence of intact Fab fragments as intermediate cleavage products. In contrast, both IgA1 and IgA2 proteins were resistant to cleavage by alkaline protease from P.

The role of the liver in catabolism of mouse and human IgA.

The fate of intravascular IgA which is produced in large quantities in humans and many animal species was investigated in vivo and in vitro with emphasis on the monomeric form of IgA. The site(s) of the catabolism of intravenously injected mouse monomeric IgA labeled with a residualizing tracer (dilactitol - 125I tyramine) was studied in mice. The greatest in vivo uptake of monomeric IgA was observed in the liver.

Receptor-mediated binding and uptake of immunoglobulin A by human liver.

We have studied the molecular mechanisms of the binding and uptake of secretory and serum immunoglobulin A (IgA) of both subclasses (1 and 2) and molecular forms (monomer and polymer) by the particulate fraction of human liver homogenate and by a human hepatoma cell line (HepG2). Inhibition by asialoorosomucoid and the requirement for the presence of calcium indicated that the binding of secretory IgA and polymeric IgA1 was mediated by the asialoglycoprotein receptor. Secretory component, which functions as a receptor for polymeric IgA in several animal species, was detected in the epithelial cells of bile ducts, but not in hepatocytes.

The stoichiometry of J chain in human secretory dimeric IgA.

Dimeric human secretory IgA was completely reduced with mercaptoethanol and alkylated with [14C]iodoacetamide. The component polypeptide chains were separated by high performance gel filtration in 5 M guanidine HCl into two fractions: one containing secretory component (SC) + heavy (H) chains; and the second containing light (L) + J chains. L and J chains were subsequently separated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS) or in alkaline urea.