Immunodiagnosis of histoplasmosis in a compromised host. (1/267)

Three serological tests for the diagnosis of histoplasmosis were compared for sensitivity and specificity in serum from blood bank donors, patients with histoplasmosis, and infected or noninfected immunosuppressed patients. The histoplasmin latex agglutination test was positive in 9% of the normal patients, 33% of the histoplasmosis patients, and 61% of the noninfected immunosuppressed patients. Since the test is prone to many false-positive results in patients with inflammatory diseases or non-Histoplasma infections, it has limited potential as a screening test among compromised patients. Immunodiffusion and counterimmunoelectrophoresis using a mycelial antigen were found to be more sensitive than either test using a combined yeast and mycelial antigen or a pure yeast phase antigen. Counterimmunoelectrophoresis at pH 7.2 proved to be the test of choice for serodiagnosis of histoplasmosis, resolving 85% of the immunocompetent infected patients and 100% of the infected immunosuppressed patients. Results indicated that counterimmunoelectrophoresis in conjunction with immunodiffusion could be used as a screening protocol to determine infection in incoming patients in a cancer hospital.  (+info)

Counterimmunoelectrophoretic detection of a high incidence of precipitin reactions in normal human sera against staphylococcal teichoic acids and protein A. (2/267)

The use of counterimmunoelectrophoresis (CIE) for detection of serum antibodies to staphylococcal teichoic acids was evaluated against teichoic acids prepared by sonic treatment or lysostaphin extraction of Staphylococcus aureus (Lafferty strain). Of 54 patient sera from suspected cases of staphylococcal endocarditis, osteomyelitis, or septicemia, 33 (61.1%) were positive by CIE analysis; however, 128 of 291 sera (44.0%) from normal adult donors were also positive. Selected CIE-positive sera from patient and control groups were titered by Ouchterlony gel diffusion. In the control group of normal sera, 65% were also positive by gel diffusion, but only 15% had titers of >/=1:2. Of the patient sera, 44.4% had gel diffusion titers of >/=1:2. In addition to the specific teichoic acid band, a second precipitation band could be demonstrated with both patient or normal sera by CIE or gel diffusion. This second precipitin band was shown to involve interactions of test sera with staphylococcal protein A present in the teichoic acid extracts. The protein A precipitins were detected at high concentrations of the antigen extracts, whereas the anti-teichoic acid precipitins were optimally detected at lower antigen concentrations. The formation of protein A precipitin bands did not correlate with the presence of anti-teichoic acid antibodies, as most sera tested were positive for protein A regardless of anti-teichoic acid activity. This study suggests that a high incidence of normal people have levels of antibodies to teichoic acids which are detectable by the highly sensitive, but nonspecific, technique of CIE.  (+info)

Detection of pneumolysin in sputum. (3/267)

Western blot detection of the species-specific pneumococcal product, pneumolysin (SPN), was shown to be almost as sensitive as PCR for the non-cultural detection of pneumococci in 27 Streptococcus pneumoniae culture-positive sputa from patients stated to have chest infections. Both techniques were considerably more sensitive than counter-current immuno-electrophoresis for pneumococcal capsular polysaccharide antigens (CPS-CIE) on the same specimens. Sensitivities for PCR, SPN-immunoblotting and CPS-CIE were 100%, 85% and 67%, respectively. In 11 S. pneumoniae culture-negative sputa taken from patients receiving antibiotics, but with proven recent pneumococcal infection, PCR and SPN-blot were positive in six (in two of which CPS-CIE was also positive), PCR alone was positive in one and SPN-blot alone was positive in one. In 11 S. pneumoniae culture-negative samples from patients not receiving antibiotics, all three tests were negative in eight, PCR was positive in three (in one of which CPS-CIE was also positive), but SPN-blot was negative in all 11. In 16 S. pneumoniae culture-negative samples from patients receiving antibiotics and with no known recent pneumococcal infections, one or more non-cultural test was positive in 11. Although further evaluation is required to assess the significance of pneumolysin detection in relation to carriage and infection and to devise a more suitable test format, these preliminary studies suggest that pneumolysin detection is a promising new approach to the non-cultural diagnosis of pneumococcal chest infection.  (+info)

Pneumococcal antigen in pneumonia. A post-mortem study with the histological and bacteriological findings. (4/267)

Pneumococcal capsular antigens can be detected in lung tissue by counter-current immunoelectrophoresis even when, following antibiotics, post-mortem bacterilogy suggests that Escherichia coli has replaced pneumococci. The results suggest that antipneumococcal therapy would benefit at least 55% of patients critically ill with lung infection and that the potentially toxic drugs directed at coliform bacteria may be unnecessary.  (+info)

Evaluation of tests for antibody response in the follow-up of patients with acute and chronic forms of paracoccidioidomycosis. (5/267)

Several serological tests have been used successfully in the diagnosis of paracoccidioidomycosis (PCM). In contrast, data about the use of these tests in the follow-up of PCM patients have been heterogeneous. In this study, serum samples from 43 PCM patients with different clinical forms were analysed by counter-immuno-electrophoresis (CIE), complement fixation (CF) and ELISA before treatment. With CIE and ELISA, the chronic unifocal form showed significantly lower antibody levels compared with chronic multifocal and acute forms. Acute form patients had significantly higher titres than patients with multifocal disease by CIE but not by ELISA. No significant differences were observed with CF. Twenty-seven of these patients were followed-up for 2 years and showed a decline in antibody levels by all three tests, paralleling clinical improvement. However, only patients with unifocal disease cleared their antibodies after 1 year of treatment as analysed by CF and ELISA and after 2 years by CIE, suggesting that these patients may need shorter courses of therapy. Patients with the other clinical form of the disease needed > or =2 years of therapy to clear their antibodies. Sera from a further five patients who presented with a relapse were analysed. At the time of relapse all showed increases in antibody levels by CIE and ELISA, but only three showed increases by CF tests. Therefore, CIE and ELISA demonstrated a better clinical correlation than CF, probably reflecting the fungal burden of PCM patients more accurately.  (+info)

Alkyl hydroperoxide reductases C and D are major antigens constitutively expressed by Mycobacterium avium subsp. paratuberculosis. (6/267)

Antigens characteristic for Mycobacterium avium subspecies paratuberculosis were identified by crossed immunoelectrophoresis (CIE) and by absorbing out cross-reactive antigens by using a polyclonal and polyvalent Mycobacterium avium subspecies avium antiserum. Two antigens were present in M. avium subsp. paratuberculosis and not detected in Mycobacterium avium subsp. avium. They were identified as antigens 17 and 20 in a CIE reference system for M. avium subsp. paratuberculosis antigens. Purified antigen 20 was identified as alkyl hydroperoxide reductase C (AhpC) while the N-terminal part of purified antigen 17 showed 80% homology with alkyl hydroperoxide reductase D (AhpD) of Mycobacterium tuberculosis. AhpC had a nonreduced mobility in sodium dodecyl sulfate-polyacrylamide gel electrophoresis corresponding to a molecular mass of 45 kDa and is probably a homodimer linked with disulfide bridges in its native form. AhpD had a mobility corresponding to 19 kDa. Monospecific rabbit antiserum against AhpC and AhpD reacted with 9 strains of M. avium subsp. paratuberculosis but not with 20 other mycobacterial strains except for a Mycobacterium gordonae strain, against which a weak cross-reactive band was produced. Goats experimentally infected with M. avium subsp. paratuberculosis had strong gamma interferon (IFN-gamma) responses toward both AhpC and AhpD, and they also had antibodies against AhpC. The ability of AhpC and AhpD to induce IFN-gamma production shows that these proteins potentially could be used in future vaccines or in diagnostic assays. These results further show that AhpC and AhpD are immunologically important proteins which are constitutively and highly expressed in M. avium subsp. paratuberculosis without the bacteria being submitted to oxidative stress and that the specificities of antigens can be a matter of different levels of protein expression in various species as well as distinct structural differences.  (+info)

Immune response in cattle vaccinated against rabies. (7/267)

In order to determine the best type of rabies vaccine to use as a booster, 78 serological samples from singly vaccinated cattle were analyzed by counterimmunoelectrophoresis technique. The animals were divided into several groups, received the first vaccine dose with modified live virus vaccine (ERA strain) and were revaccinated with inactivated virus or modified live virus vaccines. Boosters were given at 2, 4, 8, 12 and 16 weeks following first vaccination. Results showed high titres in the cases of booster with inactivated vaccine. In all cases, however, detectable antibody titres declined quickly.  (+info)

Canine experimental infection: intradermal inoculation of Leishmania infantum promastigotes. (8/267)

Five mixed breed dogs were inoculated intradermally (ID) with cultured virulent stationary phase promastigotes of Leishmania infantum Nicole, 1908 stocks recently isolated. Parasite transformations in the skin of ID infected dogs were monitored from the moment of inoculation and for 48 h, by skin biopsies. Anti-Leishmania antibody levels were measured by indirect immunofluorescence assay, counterimmunoelectrophoresis and direct agglutination test, and clinical conditions were examined. Thirty minutes after ID inoculation the first amastigotes were visualised and 3 to 4 h after inoculation the promastigotes were phagocytized by neutrophils and by a few macrophages. These cells parasitised by amastigotes progressively disappeared from the skin and 24 h after inoculation parasites were no longer observed. Local granulomes were not observed, however, serological conversion for antibodies anti-Leishmania was achieved in all dogs. Direct agglutination test was the only technique positive in all inoculated dogs. Amastigotes were found in the popliteal lymph node in one dog three months after inoculation. This work demonstrates that, with this inoculum, the promastigotes were transformed into amastigotes and were up taken by neutrophils and macrophages. The surviving parasites may have been disseminated in the canine organism, eliciting a humoral response in all cases.  (+info)

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