Search PubMed⌕ Search

Biomedical subjects

J Pillot

Publications and source records attributed to J Pillot.

195 records · Page 11Linked to original sources
PubMedDate not supplied

Use of in vivo challenge to assess rubella immunity determined by haemagglutination inhibition and latex agglutination.

In order to estimate the protection afforded by low levels of rubella antibody, pregnant women were tested by haemagglutination inhibition (HAI) and latex agglutination (LA). Fifty-nine women whose sera were HAI-negative (less than 25 IU/ml) or weakly positive (25 IU/ml) received rubella vaccine (RA 27/3) after delivery. Serum samples were collected one week and one month after immunization and tested for rubella total antibody and rubella IgM and IgA antibody. No patients found positive by HAI and LA showed any evidence of primary immunization. Furthermore, rubella IgM antibody was never detected after immunization in women who were HAI-negative and LA-positive during pregnancy. These results show that low antibody titres detected by LA are sufficient to protect individuals against infection with the attenuated virus. It is conceivable that such low titres also ensure protection against natural rubella infection.

Antibodies, Viral↗
PubMedDate not supplied

At least three epitopes are recognized by the human repertoire in the hepatitis B virus group a antigen inducing protection; possible consequences for seroprevention and serodiagnosis.

Many recent investigations have shown that both HBV and anti-HBs antibodies coexist in the same patient, and HBV can be found in individuals with anti-HBc antibodies in the absence of immunologically detectable HBsAg. In most cases, mutant forms of HBV affecting the region of the envelope gene coding for the group a determinant recognized by human antibodies have been found. The nature of the group a determinant was revisited with an ELISA involving dissociated, but not alkylated, envelope subunits. No antibody recognizing a continuous epitope of the major S envelope protein could be found in humans; the full activity of human anti-HBs antibodies appeared to be focused on the discontinuous group a determinant. The immunological human repertoire against the HBsAg group a determinant was analysed by competitive inhibition of three mouse monoclonal antibodies (mAbs) selected as recognizing three distinct specificities on the group a determinant. Antibodies to specificities #1 and 3 were found in 52/70 anti-HBs human sera and generally predominated over specificity #2, which was lacking in some sera. The heterogeneity of the group a determinant suggested by these data argue for the use of more than one type of anti-HBs mAb for seroprevention of recurrence after liver transplantation and HBs serodiagnosis. Provided all three types of mAbs characterized here recognize HBV variants with mutations in the a determinant and are virus-neutralizing, it may be helpful, after association of such mAbs, to use them for diagnosis and to devise new immunotherapeutic strategies to prevent emergence of HBsAg escape mutants.

Animals↗
PubMedDate not supplied

Delineation between T and B suppressive molecules from human seminal plasma: II. Spermine is the major suppressor of T-lymphocytes in vitro.

The nature of the human semen T-suppressor was investigated in vitro on human lymphocyte proliferations induced by phytohemagglutinin (PHA) or by alloantigens. Purification by ion-exchange chromatography, followed by butanol extraction, showed this factor to be present only in the polyamine-containing fractions. The purified product, obtained by preparative thin-layer electrophoresis, contained almost exclusively spermine and exhibited the same suppressive activity as this polyamine. Human T-lymphocyte suppression occurred in the presence of fetal calf serum, but it did not occur in a serum-free medium. No suppression was observed after preincubation of the fetal calf serum with hydroxylamine, a spermine oxidase inhibitor, whereas a nondialyzable fraction, from normal human serum, decreased the suppression. The semen factor did not act by direct cytotoxicity, as there was no effect of preincubation and suppression could be induced only within the first 6 hr of mitogen activation. These data demonstrate that the in vitro T-suppressive activity of semen can be assigned mainly to spermine and show that in vivo this suppression must require locally the presence of a spermine oxidase or related enzyme.

Animals↗
PubMedDate not supplied

[Presence of cryoprecipitates in the serum of patients with rheumatoid arthritis].

Serum samples from 140 controls (C) and from 72 patients suffering from defined rheumatoid polyarthritis (RP) were tested for cryoglobulins (CG). CG were found in 19.7 percent of C and 55 percent of RP : a highly significant difference (p less than or equal to 0.001). In the controls there was no correlation between the CG and age or sex. The RP with cryoglobulins seemed to have more inflammation, but systemic manifestations were not any more frequent than in the cryonegative RP. In the RP a correlation was noted between the presence of CG and the following parameters : increase in the sedimentation rate, rise in serum immunoglobulins, IgA and IgC, presence of antinuclear factors, and drop in the C4 fraction of complement. There was no correlation with the presence of the rheumatoid factor in the serum. In 33 cryoprecipitates in the RP, 7 contained IgG, 1 IgM, 22 IgM-IgG -- of which 11 contained C1q and 16 rheumatoid factor -- and 3 contained IgA-IgM-IgG -- of which 1 contained C1q and 2 rheumatoid factor. Some of the biochemical data support the hypothesis that likens these cryoglobulins to immune complexes.

Adult↗
PubMedDate not supplied

[Presence of antibodies in human colostral secretory IgA against enteric commensal bacteria: biological implications (author's transl)].

Antisecretory component, anti-alpha, anti-mu and anti-Fc (gamma) fluorescent antibodies were used to detect the presence of immunoglobulins with antibody activity against enteric commensal bacteria in human colostrum and serum. Forty nine colostrum samples were studied; all of them displayed secretory IgA (sIgA) antibodies reacting with Bacteroides thetaiotaomicron, Clostridium perfringens and Escherichia coli serotype O141:H32 without any K antigen. The amount of sIgA antibodies was always related to the sIgA colostral concentration varying greatly from one patient to another. For the 3 lactating women studied, the colostrum sIgA antibodies were largely predominant as compared to the antibodies of other classes; in their sera, no antibody having the same anticommensal specificity was detected in the IgA fraction while these antibodies were found in IgM and IgG. Our results are incompatible with the existence of local antigenic stimulation, and the IgA transfer from serum into mammary secretion appears unlikely, but these results are perfectly compatible with the antigenic stimulation of gut associated lymphoid tissue and subsequent migration in mammary tissue.

Antibodies, Bacterial↗
PubMedDate not supplied

[Evaluation of hepatitis B vaccination in a Paris hospital personnel. 386 subjects].

Among 471 healthy Antoine Béclère hospital workers, (61 male, 410 female) 386 with no serological markers for hepatitis B virus (HBV) received three intramuscular doses of HEVAC B at intervals of 1 month. Ninety-three p. cent of vaccine recipients showed good antibody anti-HBs levels after the third injection. Fifty p. cent of subjects with no response after the third dose seroconverted after a booster dose. Vaccine responders' mean age (30 years) was lower than vaccine non responders' mean age (36 years). Anti-HBs antibody levels were significantly higher in women (P less than 0.001) and were independently correlated with age and sex. Two vaccine recipients developed anti-HBc in addition to anti-HBs, probably due to an HBV infection that occurred just before vaccination.

Adult↗
PubMedDate not supplied

[Glomerular nephropathies and B virus: apropos of 4 cases in adults, with an immunofluorescence study and review of the literature].

The association of glomerulonephritis and persistent HBs antigenemia is reported in 4 adults with nephrotic syndrome: 2 cases of membranous glomerulonephritis associated with chronic persistent hepatitis and 2 cases of membrano-proliferative glomerulonephritis associated with active cirrhosis. In 3 patients, all positive for HBsAg, anti-HBc and HBeAg by radioimmunoassay, indirect immunofluorescent study was performed on kidney and liver biopsies. Glomerular deposit of HBcAg was detected in two cases. HBsAg and HBcAg were not found in the liver. The pathogenesis of such glomerulonephritis remains uncertain and the role of HBs antigen-antibody circulating immune complexes is not clearly proved. Two patients were treated with vidarabine intravenously. Vidarabine produced a transitory decrease of HBsAg concentration in 2 cases and a transitory loss of DNA-polymerase activity associated with a decrease of HBeAg concentration in one case. Neither seroconversion nor improvement of the glomerular disease were ascertained.

Adult↗
PubMedDate not supplied

[Characterization of the antigen in circulating immune complexes and application to the detection of streptococcal antigens in human infectious endocarditis].

Immune complexes from patients with subacute endocarditis were used to develop a methodology for characterization of the antigen involved in human circulating immune complexes. This model was chosen because it permits isolation of the causative agent of the streptococcal infection thought to contain the antigen present in the immune complex. A comparison was made between two methods for characterization of bacterial antigen bound to antibody. In the first, animals were immunized with purified immune complexes and the production of antistreptococcal antibodies was investigated. In the second method, a sandwich ELISA was developed, implying the double specificity of the immune complex (human immunoglobulin and streptococcal antigen). The latter method gave the best results, detecting antigen in the immune complexes of 8 out of 10 patients' sera. The application of this method to other immunopathological situations is discussed.

Animals↗
PubMedDate not supplied

[Anti-HBc IgM antibodies: prevalence during HB virus infection and value of studying titers].

IgM antibody to hepatitis B core antigen (IgM anti-HBc) was determined in acute and chronic hepatitis B by the immunocapture method. To avoid interference with the rheumatoid factor, F (ab')2 antibodies were used; non-specific reaction of IgG anti-HBc with anti-mu usually observed with 1/100 dilution of the serum was avoided by 1/1,000 dilution. IgM anti-HBc was positive in 100 p. 100 of the patients with acute hepatitis B (n = 32), in respectively 100 p. 100 and 70 p. 100 of the patients with complete recovery 6 and 12 months after acute illness (n = 10 and n = 10), 20.8 p. 100 of the healthy chronic HBs Ag carriers (n = 48), 80 and 85.7 p. 100 of the patients with chronic persistent and chronic active hepatitis (n = 40 and n = 14). S/N ratios (S = sample, N = negative controls) were above 5 in all patients with acute hepatitis. In patients with complete recovery, 6 to 12 months after acute illness, and in healthy chronic HBs Ag carriers, S/N ratios were above 5 in only 5 and 2 p. 100 of cases respectively whereas in patients with chronic hepatitis, the S/N values were dispersed. The main interest of the IgM anti-HBc test is to allow for the diagnosis between acute hepatitis B and acute hepatitis non B in healthy chronic HBs Ag carriers. In our patients, a S/N ratio above 5 discriminated between an acute hepatitis B and a healthy chronic HBs Ag carrier with a specificity of 98 p. 100.

Carrier State↗
PubMedDate not supplied

Detection of Legionella pneumophila antigen by ELISA in urine or experimentally infected guinea-pigs.

Guinea-pigs were experimentally infected with Legionella pneumophila. L. pneumophila antigen was detected in urine samples by a double antibody sandwich ELISA. Urinary antigen was present from the beginning of the acute phase of the disease. In two out of five cases, this antigen was found with no antibody detectable in sera by indirect immunofluorescence staining.

Animals↗
PubMedDate not supplied

[Hepatitis viruses: from the old ones to the new ones. Will the alphabet be enough to list them all?].

Viral infection is by far the most frequent cause of hepatitis. Search for the causal virus is however difficult since they cannot be cultured on most cell lines in vitro and because regulatory factors required for viral expression are found only in the human hepatocytes which cannot be maintained in vitro sufficiently long for experiments. To date, viruses A, B, C and E have been well documented. Virus D, a defective virus which only develops in association with virus B has also been identified. As have others, we have also found evidence of the existence of a non-A, non-B, non-C, non-E virus (non A-E). Currently, the diagnosis of non A-E hepatitis can only be made by elimination. Our personal experience suggests that non A-E hepatitis could be incriminated in less than 10% of the acute cases requiring hospitalization. Other viruses have been isolated. We were unable to confirm the pathogenic nature of a virus isolated in India in 1994 and assigned the letter F. Virus G has been identified in a patient with post-transfusion hepatitis and corresponding serology has been found positive in 46% of a population of drug abusers and 1.7% of blood donors in the United States. Isolates of the virus GB were first recognized in 1967. There are three viruses: Ga, Gb and Gc, belonging to the Flavivirus or Pestivirus, analogous to the hepatitic C virus. Virus G appears to be identical with virus Gc. The exact pathogenic nature of all these viruses remains to be determined. Search for new viruses would suggest that there are few new pathological situations indicating the presence of unknown viruses. This observation might mean that the alphabet will be, thankfully, largely sufficient to enumerate the hepatitis viruses.

Hepatitis Viruses↗