Expression and characterization of the gD protein of HSV-2 fused to the tetramerization domain of the transcription factor p53.

The highly immunogenic glycoprotein D (gD) of herpes simplex virus type 2 (HSV-2) is a very important element for entry of this virus into host cells. These characteristics have made this protein a very interesting HSV-2 subunit vaccine candidate. Despite efforts to prevent genital herpes using gD-based subunit vaccines, to date, clinical trials using this antigen have failed. Therefore, using a small animal model, we sought to determine if a tetramerized truncated form of gD subunit vaccine, produced by recombinant baculovirus infected insect larvae, would elicit better protection against genital herpes than a monomeric gD-2 subunit vaccine. Three out of 5 mice immunized with the tetramerized antigen produced in a baculovirus expression vector system, survived a lethal challenge with a wild type HSV-2 strain (for more than 3 weeks after challenge). In contrast, all the mice (5) immunized with the truncated protein, produced by the same methodology, died within 2 weeks after challenge. These results suggest that multimerization (increasing the structural complexity) of the truncated gD antigen might be more likely protective than the monomer form. Also the use of an alternative cost-efficient eukaryotic expression system is described.

Emerging infectious endocarditis due to Scedosporium prolificans: a model of therapeutic complexity.

Scedosporium prolificans is an emerging agent for severe infections. Although among the dematiaceous fungi Scedosporium is the most frequently isolated in blood cultures, Scedosporium endocarditis is rarely reported. We show herein a patient with acute leukaemia who developed S. prolificans endocarditis. Twelve cases were found in an extensive review of the English literature. In six cases (46%), there was predisposing heart conditions such as a prosthetic valve or an intracavitary device. Only 4 patients (31%) were immunocompromised hosts with haematologic neoplasia, solid-organ transplantation or acquired immunodeficiency syndrome (AIDS). Exposure to Scedosporium was observed in immunocompetent patients who developed infection while in the community. Scedosporium endocarditis occurred on both sides of the heart. Systemic and pulmonary emboli and other metastatic complications were seen in all of these patients. The overall mortality was 77% and, specifically, all of the immunocompromised hosts and 6 out of 7 patients with mitral or aortic valve endocarditis died. Patients with right-sided endocarditis associated with a removable intracardiac device exhibited a better prognosis. Scedosporium endocarditis, although still rare, is an emerging infection with an ominous prognosis. At the present time, valve replacement or the removal of cardiac devices plus combined antifungal treatment may offer the best possibility of cure.

Immunological properties of a DNA plasmid encoding a chimeric protein of herpes simplex virus type 2 glycoprotein B and glycoprotein D.

A DNA plasmid containing a chimeric sequence encoding both herpes simplex virus type 2 (HSV-2) glycoprotein B (gB) and glycoprotein D (gD) external domains (pcgDB) was used to immunize BALB/c mice against genital HSV-2 infection. To determine the efficacy of this vaccine, groups of mice immunized with the pcgDB plasmid were compared with animals immunized with plasmids corresponding to the individual proteins (pcgBt or pcgDt), administered separately or in combination (pcgBt + pcgDt). We studied the response of the different mouse groups to viral challenge by analyzing clinical disease (vaginitis), serum antibody levels, as well as lymphoproliferative responses and cytokine production by spleen cells. Increased IFN-gamma levels correlated with prolonged survival in mice immunized with the plasmid pcgDB, relative to mice immunized with plasmids coding for the individual proteins alone or in combination. Our results show that immunization with the plasmid encoding the chimeric protein is advantageous over separate proteins. These findings may have important implications for the development of multivalent DNA vaccines against HSV and other complex pathogens.

Nosocomial enterococcal endocarditis: a serious hazard for hospitalized patients with enterococcal bacteraemia.

OBJECTIVES: Enterococci are a major leading cause of infectious endocarditis and also a common cause of hospital-acquired bacteraemia, which is not believed to represent a serious hazard for the endocarditis. The incidence and risk factors for infectious endocarditis in patients with hospital-acquired enterococcal bacteraemia is determined. METHODS: Prospective analysis of 116 patients with enterococcal bacteraemia admitted to medical or surgical wards of a tertiary-care, university affiliated hospital during a period of 5 years. Echocardiography was performed when indicated by clinical criteria. RESULTS: Seventy-five (61.4%) episodes were hospital-acquired and 47 (38.5%) were community-acquired. Most patients had one or more underlying chronic diseases and major abdominal (58.6%) or genitourinary (38.6%) surgery. Seventeen patients (14.6%) developed enterococcal endocarditis. By univariate analysis the risk factors associated with endocarditis were community-acquired infection (P 0.012); monomicrobial bacteraemia (P 0.006); three or more positive blood cultures (P < 0.001); underlying valvulopathy (P < 0.001); presence of a prosthetic valve (P < 0.001) and age (P 0.012). Six patients (8%) developed nosocomial endocarditis. In this group of patients, three or more positive blood cultures (P < 0.01), bacteraemia as a result of Enterococcus faecalis (P 0.007); underlying valvulopathy (P < 0.001) and presence of a prosthetic valve (P < 0.001) were associated with endocarditis. By logistic regression, the presence of underlying valvulopathy and three or more positive blood cultures were associated with endocarditis (OR 21.0; CI 95% 1.65-26.9; P 0.019). CONCLUSIONS: The risk of developing infectious endocarditis in patients with hospital-acquired enterococcal bacteraemia is significant. Patients with underlying valvulopathy and three or more positive blood cultures with E. faecalis are prone to nosocomial enterococcal endocarditis.

Immunological diagnosis of human hydatid cyst relapse: utility of the enzyme-linked immunoelectrotransfer blot and discriminant analysis.

A discriminant technique was applied to the different serological patterns obtained by enzyme-linked immunoelectrotransfer blotting (EITB) and by conventional immunological tests, in order to differentiate the residual antibody patterns present in healed hydatidosis from the ones present in patients with active hydatidosis. For this purpose, specific antibodies against Echinococcus granulosus were detected by indirect hemagglutination, agglutination of latex particles, basophil degranulation, and EITB for 23 patients with active hydatidosis and 45 patients with surgically cured hydatidosis. Discriminant analysis of the different serological patterns obtained by EITB and conventional serology correctly classified 92.54% of patients (93.3% if the patients are differentiated according to the time elapsed since surgery). This method detected the presence of active hydatidosis in 95.6% of patients for whom abdominal ultrasonography had confirmed the presence of active hydatid cysts. The global specificity was 88.9%. The specificity was 97.1% for patients who had been operated on 3 years ago or more and 63.6% for patients with less time since surgery.

Papular-purpuric "gloves and socks" syndrome: polymerase chain reaction demonstration of parvovirus B19 DNA in cutaneous lesions and sera.

We report a typical case of papular-purpuric "gloves and socks" syndrome (PPGSS) in which primary infection by parvovirus B19 was demonstrated by seroconversion to this virus; parvovirus B19 DNA was also identified by polymerase chain reaction (PCR) methods in the sera of the patient and in the cutaneous biopsy specimen, both taken 4 days after the onset of clinical manifestations. To our knowledge, this is the fourth published case in which parvovirus B19 DNA has been recovered from the skin by PCR. Serologic studies and PCR investigations in cutaneous biopsy for other viruses including herpes simplex virus types 1 and 2, varicella zoster virus, Epstein-Barr virus, cytomegalovirus, and human herpesvirus 6, 7, and 8 were negative. Clinically, our case presented some additional features, which have not been previously described in cases of PPGSS, namely dysuria with vulvar edema and erythema, and unilateral petechial rash on the breast. The histopathologic findings of our case were nonspecific and consisted of an interface dermatitis with slight vacuolar degeneration at the dermoepidermal junction and a superficial perivascular inflammatory infiltrate mostly composed of lymphocytes, with numerous extravasated erythrocytes. We review the cases of PPGSS published in the literature with respect to the different viruses that have been proposed as etiologic agents and conclude that acute infection by parvovirus B19 is the only one that has been adequately proved.

Immunological diagnosis of human cystic echinococcosis: utility of discriminant analysis applied to the enzyme-linked immunoelectrotransfer blot.

An enzyme-linked immunoelectrotransfer blot for the diagnosis of human hydatid disease was performed, and the different antibody responses were analyzed by a discriminant analysis. This multivariate technique gave us, first, a selection of the most important responses against Echinococcus granulosus infection and, second, a procedure for the classification of patients into two groups: patients with hydatid disease and patients without a history of hydatid disease. This method was applied to 67 patients, 25 with active hydatid cysts (24 hepatic and 1 pulmonary) and 42 without a history of hydatid disease and was compared with the results obtained by conventional serology: indirect hemagglutination, latex particle agglutination, and basophil degranulation. An immunoelectrotransfer blot coupled to a discriminant analysis was more sensitive than conventional serological diagnosis and detected 100% of patients with an active hepatic hydatid cyst with a specificity of 100%. This method, however, failed to detect an uncomplicated hyaline pulmonary hydatid cyst.

[Induction of interleukin-6 by Borrelia burgdorferi in different cell cultures]. / Inducción de interleucina 6 por Borrelia burgdorferi en diferentes cultivos celulares.

BACKGROUND: To determine variability, if exists, in interleukin-6 (IL-6) response by different cell cultures stimulated by Borrelia burgdorferi. METHODS: Five human embryonic diploid fibroblast cell lines (three of them of lung origin) and four human synovial cell cultures were used. Induction of IL-6 was made with B. burgdorferi B31 culture and E. coli lipopolysaccharide (LPS). IL-6 was determined by a commercial EIA (Coaliza IL-6). RESULTS: All cell cultures produced IL-6 under basal conditions and responded after adding E. coli LPS. The IL-6 production after B. burgdorferi stimulation was higher than that induced by LPS with three out the four synovial cell cultures and lowest with lung fibroblasts. CONCLUSIONS: The ability of B. burgdorferi to stimulate IL-6 production depends on the nature and origin of cell cultures. This variability and the fact that the most reactive cell cultures were those of synovial precedence may correlated with some clinical aspects of the Lyme disease.

[Candida endocarditis in non-addict patients: a disease with high mortality. A clinico-pathological study of 3 cases]. / Endocarditis por Candida en pacientes no adictos: una enfermedad de gran letalidad. Estudio clínico-patológico de tres casos.

Candida endocarditis is a rare infection which occurs under particular epidemiological circumstances, such a drug addiction, immunosuppression, prolonged intravenous therapy and valvular replacement surgery. Diagnosis requires a high suspicious index and is based on the demonstration of the organism in cardiac vegetations, peripheral embolisms or in positive blood-cultures; also when valvular insufficiency murmurs, embolic phenomena and echocardiogram-proved vegetations are present. In spite of antifungal therapy and valvular replacement, the mortality rate in Candida endocarditis is still higher than 80%. Three new cases of the entity are here reported stressing the diagnostic and therapeutical difficulties.