Particle enhanced immunoaggregation of F(ab')2 molecules

The immunological agglutination reactions of physically absorbed F(ab')2 molecules onto anionic and cationic latex particles have been investigated by means of optical absorbance measurements. These measurements have been conducted under different conditions to determine the most influential factors. Surface F(ab')2 and BSA densities, particle concentration in the reaction medium and polyethylene glycol concentration are some of these factors. Sensitized cationic and anionic latexes differ considerably with respect to their colloidal stability and reactivity. As a general rule, the sensitized cationic latex has a relatively higher colloidal stability and hence, it provides reagents with a better optical response. Less than 0.025 microgram/ml of C-reactive protein has been detected using this particle enhanced optical immunoassay.

Characterization of monoclonal antibodies physically adsorbed onto polystyrene latex particles

The physicochemical and immunochemical properties of monoclonal antibodies (MAbs), adsorbed onto polystyrene latex particles, have been investigated. Both native and pH 2 pretreated MAbs were compared before and after immobilization. It was found that the antigen binding capacity of the immobilized, acidic pretreated MAbs was significantly higher than for the immobilized, native IgG molecules. This enhanced antigen binding capacity appeared to be due to an improved molecular orientation following adsorption of the monomeric, pH 2 treated IgG fraction. Additionally, experiments using F(ab')2 fragments demonstrated that the Fc portion of the MAb molecule is of major importance for achieving the enhanced binding capacity. Binding studies showed that the (apparent) affinity of native and pH 2 pretreated MAbs were similar; the K(a) values of the immobilized MAbs were higher than those of MAbs in solution.

Immunological agglutination kinetics of latex particles with physically adsorbed antigens

The influence of the properties of antigens and particles on the immunological agglutination kinetics of the antigen-coated latex particles was studied. Horse cytochrome c, hen egg-white lysozyme (HEL), bovine serum albumin (BSA), and Aspergillus sp. glucose oxidase were physically adsorbed onto the surfactant free latices of styrene-methacrylic acid (MAA) copolymer (P (S/MAA)) and polystyrene (PS). The initial rates of the immunological agglutination of these protein-coated particles initiated by the addition of antibodies were quantified by the absorbance change at a wavelength of 680 nm. The initial agglutination rates of the particles covered with smaller antigens were lower. This effect of the molecular size of antigens was larger in P(S/MAA), because small antigens are probably buried in the hydrous polymethacrylic acid layer on the surface of particles. Thus, both the molecular size of antigens and the surface properties of particles affect the sensitivity of the immunological agglutination. On the other hand, the dependence of the initial rate of the immunological agglutination on the ionic strength and pH was similar irrespective of antigen-particle systems. The initial agglutination rates were largest at an ionic strength of approximately 0.05 at pH 7.0 and decreased with increasing pH. This dependence of the sensitivity on the pH and ionic strength is attributed to the electrostatic interactions of particle-particle and antibody-particle.

Laminin immunized monkeys develop sera toxic to cultured rat embryos and fail to reproduce

In a previous study antilaminin antibodies in a monkey with a poor reproductive history were found to be the cause of serum toxicity to cultured rat embryos. In the present study four monkeys were immunized with murine tumor laminin and a fifth with bovine serum albumin. Subsequently, sera from only the laminin immunized monkeys became toxic to cultured rat embryos. This serum toxicity was not mediated by complement but did require the antibody to have a divalent structure. Finally, mating trials were conducted with two of the laminin immunized monkeys that previously had excellent reproductive histories. Based on progesterone levels and observation the monkeys continued to have normal menstrual cycles but failed to initiate a successful pregnancy following immunization in over 2 years of mating trials. These data demonstrated that antibodies against laminin could have prevented conception or could have interrupted pregnancy because of embryotoxicity or failure of implantation.

Autoantibodies to laminin and other basement membrane proteins in sera from monkeys with histories of reproductive failure identified by cultures of whole rat embryos

Head-fold-stage rat embryos cultured on sera taken from monkeys with histories of reproductive failure had an abnormality frequency of 97% compared with only 7% on sera taken from monkeys with excellent reproductive histories. For a group of these poor reproducers, the toxicity of their sera was associated with the immunoglobulin G (IgG) fraction. These IgG fractions bound to Reichert's membrane and other basement membranes of the embryo. For one monkey, the IgG specifically reacted with a 41 kDa polypeptide of Reichert's membrane, while for two others binding was to laminin, type IV collagen, and several other minor polypeptides of Reichert's membrane. For serum from one monkey, the toxicity to cultured rat embryos was eliminated by absorption with laminin but not type IV collagen.

Preclinical detection of nephrotoxicity: description of the tests and appraisal of their health significance

The prevention of renal diseases induced by chemicals requires the use of tests with which adverse renal effects can be detected at a stage when removal from exposure to the offending agent(s) may lead to complete recovery or may at least prevent an accelerated decline in renal function. The screening tests used in clinical medicine for assessing the functional integrity of the kidney are not sufficiently sensitive to attain this objective. In this review, we describe the tests currently available for detecting incipient renal damage and attempt to assess their health significance. A minimal battery of tests is recommended for the detection of groups in industry or in the general population who are at risk. If an increased prevalence of abnormal values for these parameters is found repeatedly in a population, efforts should be made to identify the causal agent(s) and, if possible, to reduce the exposure. Follow-up examinations of subjects identified in this way are also indicated, in order to define the predictive value of the detected changes better.

Search for anti-laminin antibodies in the serum of workers exposed to cadmium, mercury vapour or lead

Anti-laminin antibodies were sought for in the serum of workers exposed to mercury vapour (Hg, n = 58), lead (Pb, n = 38) or cadmium (Cd, n = 47). Thirty-one workers removed from Cd exposure for an average of eight years were also examined. Compared with control workers matched for age and socio-economic status, the prevalence of circulating anti-laminin antibodies was not increased in workers exposed to Hg (mean duration of exposure: 7.9 years and mean urinary excretion of Hg: 72 micrograms/g creatinine) nor in those exposed to Pb (mean duration of exposure: 10.6 years and mean Pb levels in blood: 535 micrograms/l). In contrast, anti-laminin antibodies were significantly more prevalent in Cd-exposed workers whose urinary Cd exceeded 20 micrograms/g creatinine. This observation was made in both currently exposed workers and in workers removed from Cd exposure (mean duration of exposure: 9.4 and 24.6 years and mean urinary Cd: 7.8 and 13.4 micrograms/g creatinine respectively). These autoantibodies were found in Cd workers with normal renal function as well as in those with increased proteinuria.

Early detection of the nephrotoxic effects of industrial chemicals: state of the art and future prospects

This paper discusses several tests that may permit the early detection of renal changes induced by long-term exposure to nephrotoxic industrial chemicals and may possibly serve as advance warning of pending renal damage. Some tests mainly attempt to assess the integrity of the glomerulus: high molecular weight proteinuria, glomerular basement membrane (GBM) antigens in blood and in urine, circulating anti-GBM antibodies, glomerular filtration rate after an acute oral load of proteins, and estimation of membrane negative charges (ie, glomerular polyanion). Others mainly attempt to identify functional and/or morphological changes at the tubular level: low molecular weight proteinuria, aminoaciduria, glucosuria, hyperphosphaturia, hypercalciuria, enzymuria, tubular antigen excretion, kallikrein, and prostaglandin excretion. Some of these tests are already routinely used, although controversy may still persist with regard to their clinical significance. Recently, new tests have been developed that may open new perspectives for assessing the significance of the early renal changes induced by chemicals.