Detection Of Soluble Antigens Research Articles

Community-acquired pneumonia caused by Legionella pneumophila (“Legionnaire's Disease”): a brief overview and clinical observation

“Legionnaire's Disease” is an acute infectious disease caused by Legionella of the Legionellaceae family. Clinical forms of legionellosis are diverse, but the risk of severe community-acquired pneumonia (СAP) is the main clinical significance. Unfortunately, as technological progress increases, epidemiological risks of foci of infection associated with artificial water systems (favorable habitat for Legionella) are increasing, which has led to numerous epidemic outbreaks and group cases of legionellosis infection recorded in the world recently. There are no pathognomonic symptoms and signs that allow it to be reliably differentiated from CAP by another etiology for “Legionnaire's disease”. An important role in the early verification of the disease is assigned to taking into account known risk factors of infection (a recent trip accompanied by possible contact with a water spray of a centralized air conditioning system) – age over 40 years, male sex, smoking, chronic concomitant diseases (diabetes mellitus, etc.), immunosuppression and timely laboratory diagnosis. The most accessible and convenient methods of primary diagnostics of community-acquired legionellosis are tests based on the detection of soluble antigen L. pneumophila serogroup-1 in urine. The treatment of Legionellosis CAP is based on antibacterial therapy, levofloxacine and macrolides are the drugs of choice. In this article, a series of clinical observations (2017 – 2019) in one of the multidisciplinary hospitals of Moscow is given as a confirmation of the clinical significance of legionella in the etiology of CAP in hospitalized patients and the need for timely diagnosis of the disease.

Detection of soluble antigen and DNA of Trypanosoma cruzi in urine is independent of renal injury in the guinea pig model.

The diagnosis of Chagas disease in humans is generally limited to the detection of specific antibodies. Detection of T. cruzi antigens in urine has been reported previously, but is not used in the diagnosis. In this study, soluble T. cruzi antigens and DNA were detected in urine samples and were associated with kidney injury and systemic detection of the parasite. We used 72 guinea pigs infected with T. cruzi Y strain and 18 non-infected guinea pigs. Blood, kidney, heart and urine samples were collected during the acute phase and chronic phase. Urine samples were concentrated by ultrafiltration. Antigens were detected by Western Blot using a polyclonal antibody against trypomastigote excretory-secretory antigen (TESA). T. cruzi DNA was detected by PCR using primers 121/122 and TcZ1/TcZ2. Levels of T. cruzi DNA in blood, heart and kidney were determined by quantitative PCR. T. cruzi antigens (75 kDa, 80 kDa, 120 kDa, 150 kDa) were detected in the acute phase (67.5%) and the chronic phase (45%). Parasite DNA in urine was detected only in the acute phase (45%). Kidney injury was characterized by high levels of proteinuria, kidney injury molecule-1 (KIM-1) and urea, and some histopathological changes such as inflammation, necrosis, fibrosis and scarce parasites. The detection of antigens and DNA in urine was associated with the presence of parasite DNA in blood and heart and with high levels of parasite DNA in blood, but not with the presence of parasite in kidney or kidney injury. These results suggest that the detection of T. cruzi in urine could be improved to be a valuable method for the diagnosis of Chagas disease, particularly in congenital Chagas disease and in immunocompromised patients.

Comparison of Rapid Malaria Test and Laboratory Microscopy Investigation for Community-Based Active Surveillance of Asymptomatic Falciparum Malaria in Yenagoa, Niger Delta, Nigeria

Dr Oboro VO 11.9999 Normal 0 false false false MicrosoftInternetExplorer4 Blood samples collected from 272 volunteers in two communities of Bayelsa State in the Niger Delta area were investigated for falciparum malaria parasite using the rapid test based on the detection of soluble antigen and laboratory microscopy test. The data showed that out of the 272 samples collected, 40(14.7%) falciparum malaria cases were identified by microscopic examination. 53(19.5%) were detected by rapid test. The Global (p.f) malaria test kit yielded 22 false negative and 35 false positive results when compared with microscopic findings. Only 18 cases shows true positive results. The specificity and sensitivity of the kit was 80% and 45% respectively when the parasite density is below 100 parasite/ µl. These results shows that rapid test would not give justifiable results as most of the low parasite density cases could escape detection, therefore, it cannot replace laboratory microscopic diagnosis in an active malaria surveillance programme in the study area. Therefore, regulatory agencies should insist on regular laboratory microscopic diagnosis in the surveillance of malaria.

Production of polyclonal and monoclonal antibodies against group A, B, and C capsular polysaccharides of Neisseria meningitidis and preparation of latex reagents

Polyclonal and monoclonal antibodies against capsular polysaccharides of Neisseria meningitidis serogroups A, B, and C were produced in order to develop immunological reagents allowing both the detection of soluble antigens during meningococcal meningitis and antigenic serogrouping of N. meningitidis cultures. The performance characteristics of monoclonal and polyclonal antibody latex reagents were compared. For the detection of soluble polysaccharide antigen, polyclonal antibody latex reagent was selected for N. meningitidis A and C. The latex reagent prepared with polyclonal antibodies against N. meningitidis B could not detect capsular polysaccharide even at 1 mg/ml. The monoclonal antibody B latex reagent which detected 100 ng of polysaccharide per ml was therefore chosen. For the serogroup identification of N. meningitidis, the use of a confirmatory test results in an overall specificity of 100% with polyclonal or monoclonal antibody latex reagents.

The diagnosis of Listeria monocytogenes serogroup 4 infections in humans by the detection of soluble antigen in cerebrospinal fluid by ELISA

With a panel of anti- Listeria monoclonal antibodies, soluble antigen was identified by ELISA in the cerebrospinal fluid samples (CSF) of patients infected by strains of Listeria monocytogenes serogroup 4. Antigen was captured by an anti- Listeria monoclonal antibody (CL2) coated on to microtitre wells, which was detected by the sequential addition of CL2 conjugated to flourescein isothiocyanate (FITC), followed by a peroxidase labelled anti-FITC monoclonal antibody. The test was 100% specific, and antigen was detected in 27% ( 18 67 ) of patients infected with L. monocytogenes serogroup 4, and in two out of 62 patients where listeriosis was suspected. Antigen was not detected in 270 other CSFs tested. Antigen was only detected in CSFs taken within seven days after onset of illness, where 52% of patients had detectable antigen.

Detection and transport of soluble antigens of Erwinia salicis and their role in symptom expression of the Watermark disease

An inproved method for the detection of soluble antigens of Erwinia salicis in leaves of Salix alba by ELISA is described. These antigens play a role in symptom expression of the Watermark disease. The antigen concentration in the leaves fluctuates strongly during the growing season. Presence of E. salicis inside willow trees could be determined without disturbing both host and pathogen.

Soluble antigens associated with infection with apple chlorotic leaf spot virus

Virus-related soluble antigens, probably various polymeric forms of viral coat protein, were detected in crude extracts from plants infected with apple chlorotic leaf spot virus (CLSV), using highly specific antisera to two CLSV strains from apple and peach, respectively. The two antisera appeared to detect the soluble antigens differently, though with about the same sensitivity. Soluble antigen preparations were clarified by ultracentrifugation of crude sap, by acidification, freezing and thawing, and by ammonium sulfate precipitation. The last treatment allowed some concentration. Detection of soluble antigen in gel diffusion tests provided a specific diagnostic test for CLSV infection in Chenopodium quinoa, but not in apple tissue.