A study of the presence of circulating immune complexes in schistosomiasis.

The sera from 51 patients with schistosomiasis were studied for the presence of circulating immune complexes (IC) using two methods, inhibition of EAC rosette formation and precipitation of radio-labelled Clq. The percentage EAC rosette inhibition was significantly greater in the total group of patients compared to the control sera. The material inhibiting EAC rosette formation was precipitable by 4% polyethylene glycol, thus excluding the role of C3 fragments and suggesting that inhibition was due to immune complexes. Using precipitation of radio-labelled Clq significant high values compared to control sera were only obtained in those patients before treatment or with an active infection. The results suggests that material behaving as IC is present in the sera of patients with schistosomiasis and that measurement of the levels of IC may be important in assessing the state of the disease.

Malaria, arbovirus and hepatitis infections in Macaca fascicularis from Malaysia.

Naturally occurring malaria, arbovirus infection and hepatitis in monkeys can be a hazard for the investigator and might interfere with the outcome of experiments. 63 young adult Macaca fascicularis from Malaysia were screened for these infections. About 1 year after their arrival in France, parasitaemia due to Plasmodium spp., was present in 6.4% of the animals and specific antibodies in 55.5%. 19 of 35 initially positive monkeys were tested again 2 years later. Parasitaemia was found in 1 of 4 monkeys and antibodies in 11 of 19 monkeys which were initially positive. 9 of the monkeys initially tested had low titres of antibodies to the Flavivirus genus. All animals were negative for the hepatitis B surface antigen and anti-HBc. The prevalence of IgG antibodies against hepatitis A was 46.0%. The implications in terms of control are discussed.

Production and characterization of monoclonal antibodies against rat brush border antigens of the proximal convoluted tubule.

In order to understand further the processes involved in immunological injury of the kidney, we have prepared monoclonal antibodies against brush border (BB) antigens of rat proximal tubule. The 27 antibodies which constitute the basis of this report have been cloned, characterized immunochemically, and classified in three specificity groups on the basis of tissue reactivity. The first group is made up of six antibodies reacting with antigens simultaneously present on BB and glomerulus: three are directed against a high molecular weight (MW) protein which migrates with an apparent MW of 330,000; two react with a 90,000 MW protein that is present diffusely on renal and intestinal BB as well as on endothelial cells; one recognizes an antigen exclusively present on superficial tubules and glomerular epithelial cells, which could not be chemically characterized. The second group is made up of eight antibodies present on renal and intestinal BB: five react with a 120,000 MW antigen, one with a 300,000 MW antigen. The third group comprises 13 antibodies. Two are directed against antigens present within the cytoplasm or the basolateral membranes of renal tubules. Eleven react with intracellular antigens probably related to the cytoskeleton. Since they have been identified through several fusions, some of the monoclonal antibodies described are probably directed against immunodominant proteins of the BB. They open new possibilities for purifying the corresponding antigens by affinity chromatography as well as for obtaining BB preparations selectively depleted of the strongest immunogens thus favouring antibody production to previously unrecognized antigens.

Characterization of monoclonal antibodies to rabbit renal cortical cells.

The immunological heterogeneity of the rabbit nephron was investigated using monoclonal antibodies. Seventeen antibodies have been produced by fusion of NS1 myeloma cells with spleen cells from BALB/c mice immunized with unfractionated rabbit renal cortical cell preparations. Sixteen antibodies reacted with proximal tubular cells: 11 with the brush border and 5 with basolateral membrane or intracytoplasmic components. Only one of the latter was specific for constituents of the proximal tubule. One antibody reacted with the cortical collecting tubule. Eight of the anti-brush-border antibodies were further characterized by immunoprecipitation of detergent-solubilized radiolabeled brush-border membrane vesicles. Seven proteins with subunits ranging in molecular weight from 90,000 to greater than 340,000 were identified. Systematic survey showed that one of these proteins with a subunit molecular weight of 115,000 exhibited leucine aminopeptidase activity. Selected monoclonal antibodies bound to Sepharose 4B immunoadsorbents were used to deplete solubilized brush-border membrane vesicles of a given antigen and to identify leucine aminopeptidase. Furthermore, the obtention of specific antibodies directed against the proximal tubule allowed us to set up a simple method for renal cell separation: isolated renal cortical cells could be depleted by 80% in proximal cells by passage over columns of Sepharose 6MB covalently linked with three different monoclonal anti-brush-border antibodies, thus leading to cell suspensions considerably enriched in tubule cells originating from the more distal segments of the nephron.

[Role of macrophages in interferon production in mice (author's transl)]. / Etude du rôle des macrophages dans la production d'interféron chez la souris.

By stimulating or depressing the macrophage system with Corynebacterium parvum or anti-macrophage serum, we were able to establish that macrophages play a role in Poly-I:C-induced interferon production. On the other hand macrophages do not seem to be the cells which produce endotoxin- or NDV-induced interferon, although a slight participation of these cells in the production of NDV-induced interferon cannot be excluded.

[Bacterial endocarditis : lack of diagnostic value of immunological investigations (author's transl)]. / Diagnostic de l'endocardite bactérienne : inutilité des explorations immunologiques.

To evaluate the diagnostic help afforded by immune determinations in feverish valvular patients, we prospectively determined: total hemolytic complement, cryoglobulin, rheumatoid factor, circulating immune complexes and direct skin immunofluorescence. Twenty patients entered the study, twelve with bacterial endocarditis, six without any bacteremia and two septicemic patients without endocarditis. We detected at least one immune abnormality in 10/12 endocarditis patients: - in 7/11 (64 p. cent) circulating immune complexes; - in 3/12 rheumatoid factor; - in 3/12 positive fluorescence in dermal vessels (IgM-C3); - and in one patient an IgG lupus-like band in the membrane basal zone. We also found circulating immune complexes in 3/4 patients without bacteremia and in 1/2 septicemic patients. We conclude that, in our small prospective study, immune abnormalities are frequent in bacterial endocarditis patients but their diagnostic values is rather limited : their absence do not rule out endocarditis and they can be present in many other febrile disorders.

A clinical and immunopathological study of 304 cases of glomerulonephritis in Tunisia.

304 cases of glomerulonephritis were biopsied in Tunisia and studied morphologically. The incidence of glomerulonephritis with marked proliferation of endocapillary cells was 60%, a figure considerably higher than in other large series. Using a Clq binding assay, statistically significant levels of immune complexes were found in cases of acute proliferative glomerulonephritis. Amongst other types of glomerulonephritis, circulating immune complexes were frequently found in systemic lupus erythematosus but only in a low percentage of primary glomerulonephritis with or without immunoglobulin deposits.

Circulating immune complexes in six patients with trichinosis.

The sera of six patients infected with Trichinella spiralis were studied for the presence of circulating immune complexes (CIC). CIC were present in all six patients studied 1 month after infection. In two patients in whom serial serum samples were available, as clinical improvement occurred there was a decrease in the level of CIC and an increase in the fluorescent antibody titres.

Circulating immune complexes and severe sepsis: duration of infection as the main determinant.

The relation between the duration of bacterial infection and circulating immune complexes (CIC) level was evaluated using the C1q binding assay in a group of patients with well defined clinical sepsis. Fifty-four patients with endocarditis and 35 with post-open heart surgery mediastinitis were prospectively studied over a period of 2 years. CIC were detected in 42% of patients studied. Interindividual variations were observed but it was found that the level of CIC increased statistically with time (P less than 0.001). CIC were statistically linked with cryoglobulinemia (P less than 0.001), rheumatoid factor (P less than 0.001) and a decreased CH50 (P less than 0.05). CIC were more frequent in patients with endocarditis (53%) than in patients with mediastinitis (24%). However, when the duration of the infection was taken into account the difference was no longer significant. No relation could be evidenced between the incidence of CIC and clinical symptoms including prognosis and renal signs. In our experience, determination of CIC does not have a critical clinical value.

Cryoglobulins, circulating immune complexes, and complement activation in cerebral malaria.

A total of 32 patients with Plasmodium falciparum malaria were studied. Of these, 23 had benign infections, and 9 had typical cerebral malaria. Cryoglobulins, circulating immune complexes detected by a C1q-binding assay, and hypocomplementemia were found in eight of nine patients with cerebral malaria. Raised levels of complement component 3 breakdown products (C3d) were found in the seven patients tested. Peak levels of circulating immune complexes and C3d were associated with thrombocytopenia. In contrast, in patients with benign Plasmodium falciparum malaria, cryoglobulins and circulating immune complexes were found only in 3 of 23 patients. Similarly, hypocomplementemia was detected only in 5 of 23 patients. These observations suggest that the intensity of the immune response and of the associated complement activation may be important factors in the pathogenesis of cerebral malaria.

[Immune complexes and complement in leprosy (author's transl)]. / Les complexes immuns et le complément dans la lèpre.

The sera of 87 Senegalese patients with various forms of leprosy were investigated. Two of the most reliable methods were used to detect circulating immune complexes : the radiolabelled C1q binding test and the Raji cell binding technique. Several fractions of complement, including C3, C4, factor B and the C3d product of C3 were also assayed. A material having the properties of immune complexes was detected in lepromatous and reactional leprosy. In tuberculous leprosy, only the Raji cell binding technique gave positive results. C3 and C4 were normal or slightly raised, but C3d was increased in all forms of the disease. There was no significant correlation between C3d values and the results of immune complexes detection tests.

Immunological segmentation of the rabbit distal, connecting, and collecting tubules.

To obtain monoclonal antibodies (MAB) specific for the different cell types of distal and collecting tubules, BALB/c mice were immunized with cell suspensions highly enriched in cells from the distal segments of the rabbit nephron. Nine MAB were selected and cloned. Four groups could be identified on the basis of double-labeling immunofluorescence (IF) on frozen kidney sections and on microdissected tubules. In addition, binding specificity at the cellular level was studied by immunoelectronmicroscopy (IEM) for selected MAB. A single MAB (group 1) was specific for distal bright cells and a subpopulation of cortical ascending limb cells. Six MAB (group 2) reacted with connecting and collecting tubules. Five of these (group 2A) had similar binding patterns and reacted identically with the two tubular segments. The MAB studied by IEM was specific for connecting and principal cells. One antibody (group 2B) reacted with only a fraction of the cells associated with the connecting tubule (CNT), but with all cells of the cortical collecting tubule (CCT). By IEM, this antibody was found to be specific for intercalated cells in CNT and bound both principal and intercalated cells of the CCT. Two MAB (group 3) reacted with antigen(s) expressed by the various terminal segments of renal tubule. MAB of groups 1 and 2A, which define distal bright cells and connecting-principal cells from the CNT-CCT, respectively, were used for cell fractionation experiments. Heterogeneous rabbit cortical cells were first incubated with the selected MAB. MAB-bearing renal cells were separated on plastic dishes previously coated with an affinity-purified goat anti-mouse immunoglobulin. Using these procedures it was possible to obtain highly purified subpopulations of distal, bright, or connecting-principal cells.