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Biomedical subjects

J Kalil

Publications and source records attributed to J Kalil.

107 records · Page 6Linked to original sources
PubMed1982

[Analysis of various isoferritins with monoclonal antibodies].

Balb/c Mice were immunized with splenic isoferritin. Spleen cells from immunized Mice were fuzed with SP2O myeloma cells. Four monoclonal antibodies designated respectively M29, M211, M386 and B8 were selected. Various isoferritins were analysed by immunodiffusion (Ouchterlony technic). With these monoclonal antibodies and with Rabbit polyclonal sera: human basic and acidic isoferritins and Horse spleen ferritin. Ferritin could be precipitated by these monoclonal antibodies. These results confirm that the ferritin molecule consists of repeating antigenic sites. No immunoreactivity difference could be detected between acidic and basic human ferritine. Species specificity was recognized. The high affinity constant of the M29 monoclonal antibody allowed development of a standardized radioimmunossay of ferritin.

Animals↗
PubMed1982

Monoclonal antibodies as a tool for phylogenetic studies of major histocompatibility antigens and beta 2-microglobulin.

The cross-reactivity of several monoclonal antibodies recognizing monomorphic determinants of human HLA-A, B, C, and DR antigens and human beta 2-microglobulin (beta 2m) has been studied on peripheral blood leukocytes in 24 different species. An monoclonal HLA-A-, B-, and C-specific antibody and four monoclonal HLA-DR-specific antibodies cross-reacted with cells from all the primate species tested. Furthermore, antibodies HLA-DR-specific were positive with peripheral blood leukocytes (PBL) from cows, goats, sheep, horses, and dogs. Two monoclonal beta 2m-specific antibodies, which were positive with PBL from certain primates, also reacted with cells from cows, goats, sheep, horses, and dogs. Two other beta 2-m-specific antibodies reacted only with PBL from chimpanzees. No reaction could be detected with all our reagents in other classes tested (birds, reptiles, amphibians, and Teleostei).

Animals↗
PubMed1982

A new Epstein-Barr virus negative Burkitt's lymphoma derived cell-line. I. Analysis of cell surface markers and abnormal expression of HLA antigens.

CHEV, a new Epstein-Barr virus negative Burkitt's lymphoma derived cell line has been studied. Karyotype analyses demonstrated the t (8; 14) characteristic translocation. Cell surface characterisation of this line showed the presence of mu and chi immunoglobulin chains and beta 2-microglobulin and the absence of the complement receptor. We are unable to detect HLA--A, B alloantigens on the cell surface which was in contrast with an apparently normal expression of these antigens in the cytoplasm.

Antigens, Neoplasm↗
PubMedDate not supplied

Towards a vaccine against rheumatic fever.

Rheumatic fever (RF) is an autoimmune disease which affects more than 20 million children in developing countries. It is triggered by Streptococcus pyogenes throat infection in untreated susceptible individuals. Carditis, the most serious manifestation of the disease, leads to severe and permanent valvular lesions, causing chronic rheumatic heart disease (RHD). We have been studying the mechanisms leading to pathological autoimmunity in RF/RHD for the last 15 years. Our studies allowed us a better understanding of the cellular and molecular pathogenesis of RHD, paving the way for the development of a safe vaccine for a post-infection autoimmune disease. We have focused on the search for protective T and B cell epitopes by testing 620 human blood samples against overlapping peptides spanning 99 residues of the C-terminal portion of the M protein, differing by one amino acid residue. We identified T and B cell epitopes with 22 and 25 amino acid residues, respectively. Although these epitopes were from different regions of the C-terminal portion of the M protein, they showed an identical core of 16 amino acid residues. Antibodies against the B cell epitope inhibited bacterial invasion/adhesion in vitro. Our results strongly indicated that the selected T and B cell epitopes could potentially be protective against S. pyogenes.

Animals↗
PubMedDate not supplied

Ullrich-Turner syndrome: relevance of searching for Y chromosome fragments.

Forty consecutive patients with Ullrich-Turner syndrome (UTS) were followed-up and investigated for the presence of Y chromosome fragments in their genomes. We used the polymerase chain reaction (PCR) to detect SRY (sex-determining region on the Y chromosome) and the sequence-tagged sites (STS) sY57, sY59, sY85, sY94, sY124 and sY157--which correspond to regions 3C (sY57 and 59), 5C, 5G, 5P, and 6F, respectively, of the Y chromosome--searching for Y fragments that could bear the putative locus (loci) for gonadoblastoma (GBY). It has been shown that the presence of GBY greatly increases the risk of dysgenic gonads to undergo malignant transformation. Among our 40 patients, we found Y-derived sequences--including SRY and the region spanning from sY57 to sY94--in two. These two patients had a marker chromosome detected by conventional cytogenetic analysis (45,X/46,X + mar). Their gonads were excised and found to be streaks. In one of the patients, we found foci of primitive sex cords (amidst the gonadal stroma), oviducts and Wolffian remnants. Fluorescence in situ hybridization (FISH) did not show Y chromosome material in her gonad-derived fibroblasts. The other girl had hyperplastic Leydig cells in the gonadal stroma, oviducts and Wolffian remnants, with signs of epididymal differentiation. PCR assays performed on DNA extracted from paraffin-embedded gonadal tissue were negative for SRY sequences in both patients. These findings show that all UTS patients should be examined for Y chromosome material, and that positive cases should have their dysgenic gonads excised due to the high risk of malignancy.

Base Sequence↗
PubMedDate not supplied

Comparative study of adenoviruses with monoclonal antibodies.

The obtainment of monoclonal antibodies for adenovirus species 4(Ad4) is described. The specificities of selected monoclonal antibodies were determined by means of viral neutralization test in cell culture, immunofluorescence and Enzyme-Linked Immunosorbent Assay (ELISA), in the presence of the following species of human adenovirus: 1, 2, 5 (subgenus C), 4 (subgenus E), 7 and 16 (subgenus B) and 9 (subgenus D). Two monoclonal antibodies species specific to adenovirus 4 (1CIII and 3DIII) and one monoclonal antibody that cross reacted with adenovirus species 4 and 7 (2HIII) were obtained.

Adenoviruses, Human↗
PubMedDate not supplied

Comparison of the fluorescent polarization (TDx) and the enzymatic competitive (EMIT 2000) immune assays for the measurement of cyclosporin A blood concentration.

Evaluation of Cyclosporin A (CyA) blood concentration is imperative in solid organ transplantation in order to achieve maximal immunosuppression with the least side effects. We compared the results of whole blood concentrations of CyA in 50 blood samples simultaneously evaluated by the fluorescent polarization immune assay (TDx) and the enzymatic competitive immune assay (EMIT 2000). There was a strong correlation between both kits for any range of CyA blood concentration (R=0.99, p<0.001). The within-run and between-days coefficient of variation were less than 4% for both assays. The cost for each CyA measurement was 50% lower for the EMIT assay when compared to the TDx assay. We concluded that the EMIT is as accurate as the TDx in measuring CyA blood concentration and has the advantage of a lower cost, as well as the possibility of widespread access to the EMIT methodology in contrast to the TDx equipment, allowing the laboratory to perform several routines within a working day.

Costs and Cost Analysis↗
PubMedDate not supplied

Autoimmunity in Chagas' heart disease.

The time scale dissociation between high parasitemia and tissue pathology, allied to the absence of parasites in the heart lesions of chronic Chagas' disease cardiopathy, casted doubt on the direct participation of Trypanosoma cruzi in tissue lesions. Moreover, the heart tissue lesions in chronic Chagas' disease cardiopathy are associated to an inflammatory mononuclear cell infiltrate, presumably the ultimate effectors of tissue damage. It has been hypothesized that the inflammatory cell infiltrate could mediate a delayed hypersensitivity process directed to the heart tissue components, an autoimmune response triggered by immunological cross-reactivity in the course of a protective immune response against some T. cruzi antigen homologous to heart proteins. However, little is known about the effector role of the T cells in the infiltrate, or about the nature of the antigen that lead to their accumulation in tissue. In this paper, we will review the published evidence on autoimmunity and immunological cross-reactivity between T. cruzi and the mammalian host, along with data generated in our laboratory. The definition of the precise role played by autoimmunity in the pathogenesis of Chagas' disease cardiopathy may have important consequences both for immunoprophylaxis and for the therapeutic approach of chronic Chagas' disease.

Antigens, Protozoan↗
PubMedDate not supplied

Usefulness of T-cell phenotype characterization in endomyocardial biopsy fragments from human cardiac allografts.

The mean numbers of cytotoxic/suppressor (CD8+) and helper/inducer (CD4+) T cells were determined in 111 successive endomyocardial biopsy fragments from eight cardiac allograft patients in an attempt to define their significance in the rejection process. Endomyocardial fragments from autopsy or donor hearts without myocarditis were evaluated as controls. The mean numbers of CD8+ and CD4+ T cells in the control group were 0.8 and 0.5 cells/field at x400 magnification, respectively. The mean numbers of CD8+ T cells per field in the cardiac allograft biopsies were 2.4, no rejection group; 5.4 mild rejection group; 11.1, moderate rejection group; and 4.9, resolving rejection group. The mean numbers of CD4+ T cells per field for the same groups were slightly lower than those of the CD8+ T cells. The number of CD8+ T cells per field reliably indicated the severity of rejection. Patients with normal numbers of CD8+ T cells and no evidence of rejection had better long-term outcomes (two or fewer moderate rejection episodes) than those with higher numbers. Analysis of the data suggests that the presence of two or fewer CD8+ T cells/field may be considered normal in the myocardial interstitium. The diagnosis of no evidence of rejection should be coupled to the presence of a normal number of CD8+ T cells. High numbers (greater than 10) of CD8+ T cells, even in absence of myocytolysis, should be treated more assertively, including the use of high doses of prednisone, because all our cases with high numbers showed a worse histologic picture at the subsequent biopsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Presence of 2 different epitopes on the human beta 2-microglobulin defined by monoclonal antibodies].

Two monoclonal antibodies recognizing monomorphic determinants on class I antigens of MHC were characterized. They were shown to recognize beta 2m by cytotoxicity inhibition studies. The epitopes recognized were different, as assayed by cross-inhibition and phylogenetical studies. One antibody recognized free as well as HLA-associated beta 2m. The other reacted with a conformational epitope which was well conserved during evolution.

Animals↗
PubMedDate not supplied

[Production of monoclonal antibodies against HBs (author's transl)].

Two BALB/c mice were immunized 4 times with a mixture of adw2 and ayw4 subtypes of HBs antigens. Their spleens were then hybridized with mouse myeloma cell line NS1. Using three different radioimmunoassays (RIA), 264 independent hybridomas were screened for anti-HBs activity. By at last one of these techniques, 95% of the colonies were positive. Selected colonies were cloned and supernatants studied by RIA and immunodiffusion techniques for specificity characterisation. Some clones recognised the common "a" subtype, and other were directed to more restricted specificities. Ascites fluid was active on RIA up to 10(7) dilution (up to 29.000 UI/ml). These monoclonal antibodies may be powerful reagent for the diagnosis and understanding of viral hepatitis B.

Animals↗
PubMedDate not supplied

Cytomegalovirus infection amplifies class I major histocompatibility complex expression on cultured human endothelial cells.

Cytomegalovirus infection, a common complication in immunosuppressed graft recipients, bears an adverse impact on graft survival. Cytomegalovirus enhances the expression of the monotypic determinants of the class I major histocompatibility complex molecule by the endothelium, possibly rendering the endothelial cells more immunogenic and prone to attack by the allogeneic lymphocytes. In the present study, we focused on the effect of cytomegalovirus on the endothelial cell expression of different class I genes, on the relation between the extent of endothelial cell infection and the class I effect, and on the time course of the class I changes induced by the cytomegalovirus infection. Cytomegalovirus infection of primary cultures of human umbilical vein endothelial cells augmented the expression of the A2, A3, and B7 class I major histocompatibility complex genes when compared with uninfected cells. beta 2 microglobulin upregulation by the infected cells paralleled the changes in specific class I expression; this effect was significant only after 7 days after infection. Double immunocytochemical staining and fluorescence-activated cell sorter analysis revealed that the class I enhancement was uniform throughout the umbilical vein endothelial cell monolayer and not restricted to the cells that expressed cytomegalovirus early or late antigens. Ultraviolet-inactivated supernatants from infected umbilical vein endothelial cell did not increase class I expression on uninfected cells. In conclusion, cytomegalovirus might affect graft survival by amplifying the changes in class I expression beyond the sites of viral replication.

Antibody Specificity↗