Selective transport of polymeric immunoglobulin A in bile. Quantitative relationships of monomeric and polymeric immunoglobulin A, immunoglobulin M, and other proteins in serum, bile, and saliva.

In 17 adults, serum, hepatic bile, and saliva samples were analyzed for their sedimentation profile of IgA and secretory component (SC), and for their concentrations of albumin, orosomucoid, transferrin, IgG, IgA, alpha 2-macroglobulin (alpha 2M), IgM, and SC. Polymeric IgA(p-IgA) averaged 13% (50-700 micrograms/ml) of total IgA in serum, 70% (43-88%) in bile, and 93% (74-98%) in saliva. Most of the p-IgA in bile sedimented with SC, which also occurred free (8-44%), and with IgM. In bile, albumin (155-1,485 micrograms/ml) was the predominant protein, followed by IgG (32-480 micrograms/ml), and total IgA (37-209 micrograms/ml). In saliva, p-IgA (72-902 micrograms/ml) predominated, followed by albumin (16-385 micrograms/ml) and IgG (9-178 micrograms/ml). Secretion-to-serum albumin-relative concentration ratios (S/S-ARCR = 1 for albumin) in bile averaged 22 for p-IgA, 1.91 for IgM, 1.28 for monomeric IgA (m-IgA), 0.70 for IgG, and 0.57 for alpha 2M, indicating for p-IgA, IgM, and to a lesser extent for m-IgA, a selective excretion into bile. In saliva, a 16-fold greater selective excretion of p-IgA (mean S/S-ARCR = 354) was found. Labeled m- and p-IgA were injected intravenously into five patients. Specific activities indicated that for p-IgA 50% was serum derived in bile, as compared with 2% in saliva, and to 85% for m-IgA in bile. In the patient with the highest excretion of 125I-p-IgA in bile, only 2.8% of the injected dose was recovered in bile within 24 h after injection. Compared with rats and rabbits, the serum-to-bile transport of p-IgA in humans is much smaller.

Changes in size, subclass, and metabolic properties of serum immunoglobulin A in liver diseases and in other diseases with high serum immunoglobulin A.

We have studied the relative contributions of monomeric (m-) and polymeric IgA (p-IgA) and of IgA1 and IgA2 to total serum IgA in healthy adults and patients with liver disease (LD) or with other diseases and high serum IgA. Serum concentration of total secretory component (SC) was also determined. In addition, fractional catabolic rates (FCR) and synthetic rates for both m- and p-IgA were measured in nine controls and nine cirrhotics. Our results support four main conclusions: (a) In healthy adults, intravascular p-IgA contributes to only 4-22% (mean 12%) of serum IgA, because its FCR and synthetic rate are approximately two times higher and four times smaller, respectively, than those of intravascular m-IgA. (b) in LD, biliary obstruction does not result in a significant increase in serum p-IgA unlike in rats and rabbits, indicating that in humans the SC-dependent biliary transport of p-IgA plays a much less significant role in selective removal of p-IgA from plasma than in rats and rabbits. (c) In contrast to biliary obstruction, parenchymal LD results in a significant and preferential increase in serum p-IgA, which in cirrhotics correlates with a selective reduction of the p-IgA-FCR. This supports a role for the human liver in selective removal of p-IgA from plasma, but another mechanism than the SC-dependent biliary transport should be considered. (d) Total SC, p-IgA, and IgA2 in serum are unlinked parameters, not necessarily reflecting mucosal events. A marked increase in serum SC occurs almost selectively in LD. Although a shift to IgA2 is suggested in Crohn's disease and alcoholic cirrhosis, a shift to IgA1 frequently associated to a shift to p-IgA occurs in chronic active LD, primary Sicca, and connective tissue diseases.

Secretion of immunoglobulins and plasma proteins from the jejunal mucosa. Transport rate and origin of polymeric immunoglobulin A.

Parameters of secretion of IgA and several other plasma proteins from the jejunal mucosa were investigated in 11 individuals who had a normal distribution of Ig-containing cells in the lamina propria and in one patient who was totally deficient in jejunal IgA and IgM plasmacytes. Jejunal samples were collected during segmental gut perfusion. The following results were obtained: (a) The secretion of polymeric IgA (p-IgA, mean equals 217 micrograms/40 cm per min) exceeded those of albumin (132 micrograms), IgG (35 micrograms), and monomeric IgA (m-IgA, 15 micrograms, or 6.4% of total IgA). About 35% of IgA was IgA2 in the jejunal secretion, compared with approximately 23% in serum. This closely corresponds to the 35 and 24% of IgA2 plasmocytes in jejunal mucosa and peripheral lymph nodes, respectively. (b) For each protein, a relative coefficient of excretion (RCE) was calculated (jejunum to serum concentration ratio expressed relative to that of albumin). RCEs of 1.41 for orosomucoid, 1.0 for albumin, 0.83 for IgG, and 0.74 for IgE and, in the deficient patient, of 0.64 for m-IgA and 0.016 for IgM were obtained. This was inversely related to the molecular weight of these proteins and indicated their predominantly passive transport into the jejunum. However, in normal individuals, the RCE of transferrin (approximately 1.11 greater than 1, P greater than 0.05), alpha 2-macro globulin (approximately 0.77), m-IgA (approximately 1.98), and p-IgA (approximately 218) exceeded the value expected from simple seepage from plasma, thus pointing to an additional role of either local gut synthesis and/or active transepithelial transport. (c) Approximately 98% of p-IgA, approximately 99% of IgM, and approximately 68% of m-IgA in jejunal secretions were derived from local production in the gut wall, as determined by 125I-p-IgA specific activities and/or by comparison between the RCE values of the deficient patient to the values of controls. Therefore, the jejunal production of p-IgA (approximately 312 mg/d per 40 cm vs. approximately 54 mg/d from bile) contributes the majority of upper intestinal IgA in humans. The active transport of plasma p-IgA across the intestinal mucosa (approximately 0.08 mg/40 cm per kg per d) contributes less than 2% of the total amount of p-IgA (4.5 mg/kg per d) that is cleared daily from plasma.

Influence of molecular size of IgA on its immunoassay by various techniques--I. Direct and reversed single radial immunodiffusion.

Immunochemically pure samples of monoclonal and polyclonal IgA were prepared from human sera and milk. Samples of various homogeneous molecular sizes were further obtained by preparative ultracentrifugations. The different behaviour of each preparation (monomer, dimer, trimer, tetramer and secretory IgA) were studied in direct (DRID) and reversed (RRID) single radial immunodiffusion using three different anti-alpha-chain antisera and IgA samples of various monoclonal and polyclonal origins. In DRID, all polymer concentrations were underestimated when using monomers as standards, on an equal weight (OD) basis. Correction factors (CFs) were calculated from monomer to polymer DRID slope ratios. The means +/- SDs of these CFs were 1.55 +/- 0.18 for serum dimers, 1.85 +/- 0.10 for trimers, 2.63 +/- 0.26 for tetramers and 2.24 +/- 0.15 for secretory IgA (84% 11S, 16% 15S). These results were confirmed by RRID.

IgA-induced chemokinesis of human polymorphonuclear neutrophils: requirement of their Fc-alpha receptor.

The influence of purified human immunoglobulins on the migration of human neutrophils (PMN) was measured in a 48-well micro chemotaxis chamber, with results expressed as percentages of maximal formyl-methionyl-leucyl-phenylalanine (FMLP)-stimulated chemotaxis. Both monomeric and polymeric IgA, of both subclasses, in monoclonal and polyclonal form, as well as secretory IgA and Fc-alpha, but not Fab-alpha fragments, enhanced PMN migration when present either in the lower or in both compartments of the chamber (chemokinesis) at concns as low as 0.1 mg/ml. IgM and IgE had no such effect. In contrast, IgG was chemotactic at low concn (0.1 mg/ml). Both monomeric and polymeric IgA decreased the maximally induced FMLP-chemotaxis, but IgA increased chemotaxis induced by suboptimal levels of FMLP. Binding of 3[H]-FMLP to PMN was not affected. Cytofluorographic analysis revealed that, under the conditions of the assay, IgA did bind to 93% of PMN. Thus, the various forms of IgA have a dual effect on human PMN mobility: (1) increase PMN random migration (chemokinesis); and (2) decrease the maximal FMLP-induced chemotaxis. Our data support the requirement of binding of IgA to the Fc-alpha receptor of PMN for expression of these activities. This effect of IgA on PMN mobility may be relevant in IgA deficiency states.

Monoclonal antibodies against isotypic and isoallotypic determinants of human IgA1 and IgA2: fine specificities and binding properties.

We have analysed and compared the fine specificity and behavior in various immunoassays of 10 mouse monoclonal antibodies, from three independent laboratories, directed against IgA1, IgA2 or non-IgA2m(2). The following observations were made. (1) Although all of the monoclonal antibodies were specific for a particular IgA subclass or isoallotype in a radioimmunoassay, three of them were not specific when tested in indirect immunofluorescence on plasma cells derived from pokeweed-activated peripheral blood lymphocytes. In this highly sensitive system, contrary to direct immunofluorescence previously performed using formalin-fixed lymphoid tissue, the anti-IgA1 69.114 reacted with some of the IgA2 plasma cells, the anti-IgA2 DLDB7 reacted with some of the IgA1 plasma cells and the anti-IgA2 16.512 dimly reacted with all IgM plasma cells. (2) Among the eight anti-IgA subclass antibodies, seven were directed against the CH2 domain of IgA whereas the anti-IgA1 1-155-1 recognised an epitope destroyed by Streptococcus sanguis IgA1 protease and localised in the hinge region of IgA1. The two anti-isoallotype antibodies were directed against epitope(s) probably localised in the 65 C-terminal amino acid residues of the alpha-CH3 domain. All of the 10 antibodies were able to react with endogeneously produced surface IgA on B-cells. (3) Using monoclonal anti-IgA subclass antibodies in radioimmunoassay may be hazardous in the absence of knowledge of their affinity constants and of careful control experiments: some of the antibodies were not sensitive in radioimmunoassays designed to measure the serum titer of specific IgA1 and IgA2 antibodies. Moreover, major differences were observed between the different monoclonal reagents with respect to the influence of the size of IgA on a solid-phase sandwich radioimmunoassay. While three of the anti-IgA1 underestimated dimeric IgA relative to monomeric IgA, the fourth anti-IgA1 and all the anti-IgA2 overestimated dimeric IgA relative to monomeric IgA, by a factor sometimes close to 7.

Influence of molecular size of IgA on its immunoassay by various techniques. III. Immunonephelometry.

The influence of size heterogeneity of IgA on its immunonephelometric (IN) assay was studied using highly purified preparations of monoclonal (MC) or polyclonal (PC) monomeric (M), dimeric (D), trimeric (T) and tetrameric (Q) IgA, as well as of secretory IgA (sIgA). Concentrations measured by optical density (OD) were compared to IN--concentrations obtained by using M as standards, on an equal weight basis. No significant difference was found between OD and IN concentrations of D, T, Q and sIgA were only slightly underestimated, with correction factors (CF) of 1.16, 1.20 and 1.24, respectively. The value of 1.24 for our sIgA sample (84% of 11S, 16% of 15S) could be due to the fact that secretory component represents about 20% of the mass of the sIgA molecule. IN seems a method of choice for measuring IgA concentrations in the range of microgram/ml, almost independently of the size of IgA.

A solid phase, direct competition, radioimmunoassay for quantitation of secretory IgA in human serum.

A solid phase radioimmunoassay is described for measurement of secretory IgA (sIgA) in human serum. The assay is based on direct competition between sIgA in serum and purified labelled milk sIgA for anti-secretory-component antibodies coated on disposable plastic cups. The assay is relatively rapid, reproducible and of adequate sensitivity. A wide range of sIgA concentrations (5--120 microgram/ml) can be tested with the same dilution of human serum. The arithmetic mean +/- S.D. of the serum sIgA levels of 120 random blood donors (both sexes) was 10.9 +/- 4.6 microgram/ml. Compared to previously published methods and results of quantitation of sIgA in human sera, the present assay is an improvement which should yield interesting data in human hepatic physiopathology.

Non-proteic immunogenic impurity in proteins purified by preparative electrophoresis on Pevikon.

Purified IgA proteins, obtained by zonal electrophoresis on blocks of Pevikon, contained an uncharged, non-proteic, water-soluble macromolecular impurity. The contaminant, which precipitates in half-saturated ammonium sulfate, could be an unknown derivative of polyvinyl alcohol. It was discovered because it induced the synthesis of specific precipitating antibodies in a rabbit used for antibody production against the electrophoresed protein, generating spurious precipitin reactions during its immunochemical analysis. Thorough washing of the Pevikon will substantially reduce the amount of impurity and the danger of obtaining precipitating antibodies against it after injection into animals.

Influence of molecular size of IgA on its immunoassay by various techniques. II. Solid-phase radioimmunoassays.

Homogeneous, polymeric (P), monoclonal (MC) and polyclonal (PC) samples of purified IgA, as well as of secretory IgA (sIgA), were compared to their corresponding monomeric (M) forms with regard to their respective behaviour in both a solid-phase double antibody (AB) immunoradiometric assay (IRMA) and a solid-phase competition radioimmunoassay (CRIA). On an identical weight basis, both assays underestimated the P forms. Correction factors (CF), i.e., optical density (OD) versus radiometric concentration ratios, were calculated for both methods for all P forms, using M as standards. IRMA CF were respectively 1.50 for dimer, 1.98 for secretory IgA and 2.40 for tetramers, very similar to those obtained in radial immunodiffusion (RID). With optimally coated beads, these CF were stable along a wide range of concentrations. In contrast, CRIA-CF were 3-4 times larger and displayed much variation along their standard range of concentrations, preventing the use of a constant CF along the standard curve. Our present IRMA, with its CF, should be of value for a more accurate quantitation of small amounts of IgA of various known sizes.

Typing of subclasses and light chains of human monoclonal immunoglobulins by particle counting immunoassay (PACIA).

The subclasses of monoclonal IgGs and IgAs were identified by particle-counting immunoassay. The principle of the test is the inhibition of the agglutinating activity of either specific antisera or monoclonal antibodies (for IgA only) on latex particles coated with a monoclonal IgG or IgA of known subclass. The feasibility of assay of polyclonal Ig subclasses was demonstrated. However, the anti-IgG2 antiserum cross-reacted with an allotype (nG4m(b)) of IgG4. The possibility of typing monoclonal Igs for light chains by the same technique was also demonstrated. Results are obtained in 30 min, and the method requires only small amounts of purified immunoglobulins (Igs) and antisera or monoclonal antibodies.

Study of IgA in the cerebrospinal fluid of neurological patients with special reference to size, subclass and local production.

IgA was assayed by particle counting immunoassay in cerebrospinal fluid (CSF) from non-neurological and neurological patients. Reference values had a logarithmic normal distribution with a mean of 1.54 mg/l and an upper limit of 5 mg/l. To estimate the possible intra-blood-brain barrier (BBB) production of IgA we have calculated an IgA index: CSF-IgA/serum-IgA: CSF-albumin/serum-albumin. Values higher than the upper reference limit of 0.41 were found in 12 out of 67 patients with multiple sclerosis (18%), in 5 out of 11 with aseptic meningitis, in 7 out of 8 with herpetic encephalitis, in 1 out of 8 with Guillain-Barré syndrome and in 2 cases of tuberculous meningitis. However, this index does not take into account the relative proportions of monomeric and polymeric IgA in CSF and serum. We therefore ultracentrifuged 17 paired CSF and serum samples and determined the relative proportions of monomeric and dimeric IgA and calculated the indices for monomeric and dimeric IgA. In controls the proportion of dimeric IgA in CSF was below 5% of total IgA whereas this proportion was increased up to 53.9% in the case of intra-BBB production of IgA, which is thus characterized by a very high dimeric IgA index. In all cases IgA1 remained the predominant subclass. These results had to be compared with those observed in cultures of peripheral blood lymphocytes, which secrete about equal proportions of monomeric and polymeric IgA pertaining to the IgA1 subclass.

Characteristics of IgA deposits in liver and skin of patients with liver disease.

The presence of IgA deposits in a continuous pattern along hepatic sinusoids is a specific entity for alcoholic liver disease. In superficial skin blood vessels of patients with liver disease, IgA deposits can occur. The authors characterized the deposits for IgA-subclass epitope expression and for macromolecular configuration (assessment of [hidden] J-chain determinants and of secretory component-binding capacity). A variety of monoclonal anti-IgA-subclass reagents were applied, which proved to be specific in control experiments on blastoid cells generated by pokeweed mitogen stimulation of blood mononuclear cells and frozen tissue sections of normal jejunum. IgA1 is the major component in IgA deposits in liver (n = 83) and skin (n = 31) of patients with liver disease. Macromolecular IgA is detectable in only one-fifth of the cases. The authors' data do not indicate that hepatic IgA deposits in liver disease are of gastrointestinal origin. Out of the circulating IgA pool, IgA1 appears to be most capable of being deposited in tissue.

[IgA and its different molecular forms in the mesenteric, portal and peripheral venous blood in man]. / L'IgA et ses différentes formes moléculaires dans le sang veineux mésentérique, portal et périphérique chez l'homme.

The aim of this study was to assess the role of mesenteric blood in polymeric IgA (p-IgA) and IgA2-transport from the intestinal mucosa into plasma and the role of the liver in the clearance of these molecular forms of IgA. The concentrations of IgA, p-IgA and IgA2 were measured in mesenteric, splenic, portal, and hepatic veins of 7 control subjects without liver disease and in portal and peripheral veins of 4 patients with alcoholic cirrhosis. In control subjects, the concentration of the different molecular forms of IgA were not significantly different in mesenteric and in splenic vein. No significant decrease of IgA concentrations was observed in hepatic vein, as compared with portal vein. In cirrhotic patients IgA concentrations were significantly higher than in control subjects, but concentrations of IgA, p-IgA and IgA2 were not different in portal and peripheral blood. These results show that mesenteric vein is not a major way for p-IgA and IgA2 from the gut lamina propria to plasma, and suggest that the origin of a significant part of these molecular forms of IgA could be peripheral lymph-nodes more than gut-associated-lymphoid-tissue. The absence of significant clearance of p-IgA by the liver in normal subjects suggests that abnormalities of hepato-biliary transport of p-IgA is not responsible for the increased IgA levels observed in cirrhotic patients.

Dose equivalent measurements at a 2.7 GeV proton accelerator and comparison with the Moyer model.

The Moyer model, based on a semi-empirical method validated in the 7.4 to 350 GeV energy range, is generally used to calculate lateral shielding for high energy proton accelerators. Measurements made for the Saclay Synchrocyclotron, Saturne, have enabled the parameters corresponding to a 2.7 GeV model to be studied for different target thicknesses and angles of observation. These studies show how new data have been used to modify the equations of the model.

Radiation protection for an ultra-high intensity laser.

Radiological characterisation of an experimental chamber and other areas of an ultra-high intensity laser facility (-terawatt) revealed significant levels of X ray, gamma and neutron radiation. Different techniques were used to detect and measure this radiation: TLD. photographic film, bubble detectors and germanium spectrometry. A test series of radiological measurements was made for 150 laser shots (300 femtoseconds) with energies in the 1 to 20 J range and a target illuminance of 10(19) W.cm2. Gamma dose equivalents in the vicinity of the chamber varied between 0.7 and 73 mSv. The dose equivalent due to the neutron component was evaluated to be 1% of the gamma dose equivalent. The amount of radiation generated depends on the laser energy and the nature of the target. No activation or contamination of the chamber or target holder were observed. Ultra-high intensity lasers are being extensively developed at the present time and the investigations performed demonstrate that it is necessary to take radiological risks into consideration in the design of ultra-high intensity laser facilities and to define personnel access conditions.

Radionuclide and radiation protection data handbook 2nd edition (2002).

This handbook is a reference source of radionuclide and radiation protection information. Its purpose is to provide users of radionuclides in medicine, research and industry with consolidated and appropriate information and data to handle and transport radioactive substances safely. It is mainly intended for users in low and intermediate activity laboratories. Individual data sheets are provided for a wide range of commonly used radionuclides (144 in total). These radionuclides are classified into five different groups as a function of risk level, represented by colours red, orange, yellow, green and blue, in descending order of risk.

A method to assess predominant energies of exposure in a nuclear research centre--Saclay (France).

A study of dosimetric errors is under way within an international collaborative study of cancer risk among workers in the nuclear industry. The objective is to quantify errors in the estimated photon doses to individual organs used for cancer risk estimation. One source of errors is the response of old dosemeters in workplace exposure conditions. As these conditions are not well known, the International Study must rely on expert estimations. This paper describes a method to assess the proportion of the dose from photons in three energy ranges (< 100, 100-300, > or = 300 keV) using the responses under filters of a multi-element dosemeter. The method was tested on experimental and simulated data and provides a good estimate of the proportion of dose from photons below 100 keV, the most critical for dosemeter response. It was applied to personnel readings in one facility, confirming the experts' estimation. Beyond the International Study, the method has implication for the monitoring and protection of workers.