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Clinical signs of hyperviscosity syndrome in a 6-year-old dog included listless-ness, polydipsia, anorexia, vomiting, and recurrent bleeding from the gums. Fundoscopy showed the typical retinal changes associated with this syndrome. A polymeric IgA cryoglobulin characterized in the dog’s serum was later isolated and structurally studied. It was found to contain J chain but no secretory component. The heavy and light chains were covalently bound.

The clinical value of a scaled- down prototype of an extracorporeal plasma ultrafiltration system for the treatment of acute serum sickness in rabbits was examined. The system uses two filters: the primary separates red cells from plasma, and the secondary filter excludes high molecular weight proteins from plasma. In vitro and in vivo experiments showed that the secondary filters rejected substantially more IgM (80-90%) than IgG (10-30%) or albumin (10%) and totally rejected immune complexes (IC) prepared in vitro. Two groups of rabbits were submitted to either sham filtration with the primary filter only (n = 5), receiving back the remixed components of their blood, or to the complete ultrafiltration protocol (n = 7), with removal of high molecular weight proteins and IC. Several parameters were studied longitudinally, such as circulating IC, which appeared to rise more slowly in animals whose blood was ultrafiltered, and total proteinuria, which appeared to remain at lower levels in the same animals. Histologic examination of the kidneys, collected after killing, showed evidence of glomerular IC deposition in three of five sham-treated animals (a similar frequency to that observed in a separate group of five rabbits with acute serum sickness), while one of six treated animals had evidence of glomerular deposition of IC. These observations are tentative because of the small number of animals in each group, but are encouraging. Further studies with larger groups of animals are needed to determine whether the observed effects are reproducible and to better characterize the factors directly related to the removal of circulating IC.

Il est bien connu que les immunoglobulines IgG maintenues longtemps a des temperatures voisines de 0 °C sont denaturees. L'addition de penicillamine au serum peut accentuer cette denaturation. Dans ces conditions, les immunoglobulines du type IgG3 sont les plus sensibles et le traitement par la penicillamine peut etre utilise pour les identifier.

The evolution of proteinuria in rabbits with experimentally induced chronic serum sickness was followed up longitudinally by analytical and quantitative assays. The results suggest that sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) is a more sensitive index of kidney malfunction than are total-protein assays or the quantitation of albumin and lysozyme. In some rabbits that showed abnormal proteinuria by SDS-PAGE, no histologic evidence of pathologic damage or of deposition of immune complexes in the kidneys was found. This suggests that SDS-PAGE may detect functional alterations at early stages of kidney damage when the lesions are either undetectable or reversible. In one rabbit that was killed after normalization of the proteinuria, immunofluorescence tests indicated deposition of C3, IgG, and fibrinogen, but there was no histologic evidence of kidney damage.

Immunostaining paraffin sections of appropriately fixed tissues with an antiserum to human urinary lysozyme as the primary step in an immunoglobulin-peroxidase bridge method has localized lysozyme in previously recognized sites such as Paneth cells, renal tubules, and lymph node macrophages in several species. In addition, lysozyme was demonstrated in the ciliary layer of the trachea, and type II pneumocytes, as well as cells of presumed mucoid nature in laryngotracheal glands. Large stellate cells in follicle centers in the lymph nodes and spleen and in the medulla of the thymus evidenced strong lysozyme reactivity. Granular pneumocytes disclosed immunoreactivity for lysozyme also at the ultrastructural level. Lysoplate assay demonstrated lysozyme in abundance in both the cellular pellet and acellular supernatant of rat alveolar wash fluid and in rat lung after repeated washing of alveoli. Hamster lung differed from the others in failing to immunostain for lysozyme and affording no evidence for content of lysozyme as determined by lysoplate assay. Sites stained with antiserum to human urinary lysozyme failed to stain with antiserum to egg white lysozyme. However, the pyloric glands, Golgi elements in intestinal epithelium, the surface of the colon, and the proximal straight renal tubule of the mouse stained exclusively with the antiserum to hen egg white lysozyme. Many sites staining with antiserum to urinary lysozyme in respiratory, renal, and lymphoid tissue lacked reactivity in control sections exposed to this antiserum after it was absorbed with purified urinary lysozyme. However, mucous acini in submandibular glands, although failing to stain with other control procedures, retained towared the absorbed antiserum, possibly through reacting with an antibody other than that for human urinary lysozyme. A number of cell types containing proteinaceous cytoplasmic granules stained in control sections exposed to normal serum in place of antilysozyme serum in the immunoglobulin-peroxidase bridge procedure and, thus, possessed selective, but nonimmunospecific affinity for immunoglobulin. Cell types that stained with antiserum to hen egg white lysozyme lost affinity for the antiserum after its absorption with egg white lysozyme but retained the affinity after absorption with urinary lysozyme.

Use of the newly developed laser nephelometer provides a sensitive immunochemical assay for lysozyme in dog sera by detection of antigen-antibody complexes formed upon cross-reaction with sheep-anti-human lysozyme. Results of lysoplate and nephelometric assays correlate well.

The effects of immune complex formation on human platelets were tested in vitro using tetanus-toxoid and rabbit anti-tetanus toxoid for immune complex formation and washed human platelets. The antigen-antibody reactions took place at 37 degrees C in a stirred cuvette, constantly monitored. To this cuvette we added initially a platelet suspension and a dilution of antibody, and after this mixture reached equilibrium, antigen was added. Platelets aggregated as a consequence of immune reactions taking place at antigen-antibody ratios ranging from four times antigen excess to twenty times antibody excess (relative to equivalence). Platelets also aggregated as a result of reactions in which heat-inactivated antiserum was used, although in a more narrow range of Ag:Ab concentrations, suggesting that complement is not essential for their stimulation but may help in stabilizing the Ag:Ab reaction. Our observations provide indirect evidence in support of the involvement of human platelets in the pathogenesis of immune complex-mediated hypersensitivity reactions.

A wide variety of tests for the detection of circulating immune complexes (IC) has been proposed by different authors, but there is very little to no information concerning the performance of IC screening assays in samples known to contain in vivo-formed IC. The purpose of our investigation was to compare the behavior of a non-specific assay, the PEG-IgG screening test for IC, with an antigen-specific assay in serum samples sequentially obtained from rabbits to which we induced acute serum sickness. Five animals were used in the study; we were able to detect an increase of IC constituted by the heterologous antigen (human serum albumin) and corresponding antibodies in all, and in 4 animals the results of the PEG-IgG assay closely correlated with the results of the antigen-specific assay (rho values between 0.975 and 1.00). The 4 animals in which IC showed a definite peak by both assays developed proteinuria and IC deposits at the glomerular level, while the animal that failed to develop IC detectable by the PEG-IgG test remained normal throughout the study. These results demonstrate the ability of the PEG-IgG test to detect in vivo-formed IC and suggest that the IC detected by this test have pathogenic potential.

Histologic and immunofluorescence studies were performed in nine rabbits after daily administration of human serum albumin at a fixed dosage for periods up to 26 weeks. All but one of the rabbits studied by immunofluorescence showed IgG, C3, and fibrinogen deposits in the renal glomeruli and in the tubules or peritubular tissues. In most cases, human serum albumin could also be identified in the deposits. In two rabbits killed at week 10, kidney pathology was minimal; in one of the rabbits killed in the early phases of the disease and in all rabbits killed after week 20, there were obvious pathologic changes affecting glomeruli, tubules, and/or interstitium. Tubulointerstitial changes were absent in only one of the rabbits killed at late stages of human serum albumin administration, in spite of evidence of tubular deposition of immune complexes. These observations suggest that tubulointerstitial damage is at least as frequent as glomerular damage during the induction of chronic serum sickness.

The methods currently available for quantitative determination of lysozyme are based on the capacity of the enzyme to lyse Micrococcus lysodeikticus. Previous attempts to develop immunochemical assays have been reported, but the sensitivity was inferior to that of the most widely used lysoplate method. We describe the development of a sensitive immunochemical method for lysozyme assay in which the recently developed laser nephelometer is used. The sensitivity so achieved is at least comparable to that of the lysoplate method, and in some circumstances better. Results obtained by the lysoplate assay and the nephelometric assay correlate well. Among the advantages of our method are easier handling of larger numbers of samples, quicker results, and the possibility of assaying enzymatically inactive forms of the enzyme.

DBA/2 mice bearing a syngeneic mammary adenocarcioma T1699 produced high levels of tumor-specific antibody, detected by indirect immunofluorescence and subsequently identified as the IgG2a subclass. Tumor-bearer sera passively administered to normal recipients protected the animals from subsequent challenge with T1699 tumor cells but not from challenge with a non-cross-reacting syngeneic tumor, SaD2 fibrosarcoma. Administration of sera prior to tumor challenge was found to be more effective than treatment after the challenge. The protective effect of sera appeared to parallel both antibody titers and appearance of concomitant immunity; however, sera absorbed with T1699 cells, with the indirect fluorescent antibody titers reduced more than 100-fold, conferred an almost identical level of protection. Immune suppression of serum recipients before serum transfer abolished the effect, suggesting that protection depended on a cellular immune response by the host in addition to the possible protective effect(s) of humoral antibody.

A semi-quantitative assay method was used to study the distribution of IgG heavy chain sub-classes in normal IgG and the fractions obtained from it by isoelectric focusing, and in the residual IgG from hypogammaglobulinaemic sera.