Serodiagnosis and Immunotherapy in Infectious Disease最新文献

An indirect fluorescent antibody (IFA) test using Leishmania donovani promastigote and amastigote antigens for diagnosis of kala-azar was evaluated in a kala-azar endemic area of Bihar, India. The test was found to be highly sensitive and specific using the promastigote antigen. It was positive in about 99% of parasitologically proven cases (n = 105), 89% of clinically suspected cases (n = 70) and all the sodium antimony gluconate (SAG) resistant cases (n = 80). None of the non-endemic control subjects (n = 40) or subjects infected with tuberculosis (n = 20), leprosy (n = 28), malaria (n = 20) and amoebiasis (n = 20) showed positive response. Only about 3% of the control subjects (n = 70) of the endemic area showed false positive response. Similar results were obtained with the amastigote antigen.

A model for acute Pseudomonas pneumonia was established in mice with a mucoid, cystic fibrosis derived strain. Protection from pneumonia was achieved by intratracheal administration of hyperimmune globulins. The fate of intratracheal antibody was determined from lung lavage fluids and serum by a dot-ELISA test. Total and differential cellular changes in the lung were observed after immune globulin administration. Opsonophagocytosis assays with alveolar macrophages and PMNs elicited into the lungs showed that complement did not affect the bactericidal activities of either phagocyte. Conclusion: In mice, intratracheal administration of immune globulins against P. aeruginosa provided effective protection against acute pneumonia. The immediate availability of immune globulins in the lungs, and phagocytes are critical factors for clearance of the infecting dose of bacteria.

The increasing use of pre-admission antibiotics has resulted in decreasing numbers of meningococcal infections which are confirmed by isolation of the causative organism. The imminent availability of new vaccines for meningococcal disease necessitates the application of non-culture diagnostic methods for the confirmation of meningococcal infection. A PCR assay, based on the novel meningococcal insertion sequence IS1106 as previously described, was examined as a possible method for the non-culture diagnosis of meningococcal infection in CSF and sera. The PCR assay was adapted to a PCR-ELISA format incorporating hybridization with a specific biotinylated oligonucleotide probe for use in routine non-culture confirmation of meningococcal infection. Improvements in both specificity and sensitivity were achieved resulting in sensitivities and specificities of 64% and 100% for CSF, and 16% and 100% for serum, respectively. Analysis of the IS1106 sequence indicated further increased sensitivity may be achieved by alteration of the primer sequences.

A radioimmunoprecipitation assay (RIPA) using in vitro translated protein was developed to measure serum antibodies to the major outer membrane protein (MOMP) of C. trachomatis. Polyclonal animal antisera to C. trachomatis serovars C, E and F reacted to serogroup-specific determinants by RIPA, as compared to species-specific epitopes by Western blot. Antibody responses in monkeys immunized systemically or mucosally with a candidate MOMP vaccine were assessed by RIPA and ELISA with elementary bodies (EB-ELISA). Unlike EB-ELISA, RIPA showed a significant difference in pre-challenge antibody levels between systemically and mucosally immunized animals. Additionally, only RIPA showed a significant inverse correlation between antibody level at time of challenge and microbiologic response measured as median inclusion forming units (IFU) in culture (r = −0.89; P < 0.001). RIPA using in vitro translated proteins is a useful method to measure antibody responses to specific C. trachomatis antigens and may be more informative than EB-ELISA and Western blot for assessing the immunogenicity of MOMP vaccines.

Immune responses were studied in 19 adult male Vietnamese patients with bacillary dysentery. Shigella flexneri was isolated in faeces from 17 patients (S. flexneri 2a (n = 11), S. flexneri 4a (n = 4), S. flexneri 3a (n = 1), and S. flexneri 3b (n = 1)) and S. dysenteriae 2 was isolated from 2 patients. Thirty healthy, adult males, without diarrhoea 3 months prior to the study, served as controls. The use of enzyme immune assay (EIA) showed that S. flexneri infected patients developed intestinal sIgA responses against S. flexneri Y lipopolysaccharide (LPS) and Shigella invasion plasmid antigens (Ipa), with peak values seen 2 weeks after the onset of diarrhoea. The sIgA titres were significantly higher (0.001 < P < 0.05 for anti-Shigella Ipa sIgA and 0.01 < P < 0.05 for anti-S. flexneri Y LPS sIgA) in the patients than in the healthy controls. Enzyme-linked immunospot (ELISPOT) analyses of peripheral blood mononuclear cells (PBMC) showed that S. flexneri infected patients developed significant antibody secreting cell (ASC) responses against S. flexneri Y LPS and Shigella Ipa (0.001 < P < 0.05), which peaked 1 week after the onset of diarrhoea. IgA-ASC predominated, followed by IgG-ASC, whereas IgM-ASC were least common. The number of Shigella Ipa-specific ASC was higher than the number of S. flexneri Y LPS-specific ASC. With use of EIA it was shown that S. flexneri infected patients had significantly (0.001 < P < 0.05) higher serum IgA and IgG titres than the healthy controls. All 17 patients had anti-S. flexneri Y LPS titres, and 11 patients had anti-Shigella Ipa titres exceeding the cut-off titres (mean ± 2S.D.) seen in the controls. The highest IgA titres were seen 1 week, and the highest IgG titres 2 weeks, after the onset of diarrhoea.