RESUMEN
Burkholderia pseudomallei (Bp) and Burkholderia mallei (Bm), the agents of melioidosis and glanders, respectively, are Tier 1 biothreats. They infect humans and animals, causing disease ranging from acute and fatal to protracted and chronic. Chronic infections are especially challenging to treat, and the identification of in vitro phenotypic markers which signal progression from acute to persistent infection would be extremely valuable. First, a phenotyping strategy was developed employing colony morphotyping, chemical sensitivity testing, macrophage infection, and lipopolysaccharide fingerprint analyses to distinguish Burkholderia strains. Then mouse spleen isolates collected 3-180 days after infection were characterized phenotypically. Isolates from long-term infections often exhibited increased colony morphology differences and altered patterns of antimicrobial sensitivity and macrophage infection. Some of the Bp and Bm persistent infection isolates clearly displayed enhanced virulence in mice. Future studies will evaluate the potential role and significance of these phenotypic markers in signaling the establishment of a chronic infection.
Asunto(s)
Burkholderia mallei/aislamiento & purificación , Burkholderia pseudomallei/aislamiento & purificación , Muermo/microbiología , Melioidosis/microbiología , Animales , Burkholderia mallei/patogenicidad , Burkholderia pseudomallei/patogenicidad , Línea Celular , Femenino , Lipopolisacáridos/análisis , Macrófagos/microbiología , Ratones , Ratones Endogámicos BALB C , Fenotipo , Bazo/microbiologíaRESUMEN
We developed a microarray platform by immobilizing bacterial 'signature' carbohydrates onto epoxide modified glass slides. The carbohydrate microarray platform was probed with sera from non-melioidosis and melioidosis (Burkholderia pseudomallei) individuals. The platform was also probed with sera from rabbits vaccinated with Bacillus anthracis spores and Francisella tularensis bacteria. By employing this microarray platform, we were able to detect and differentiate B. pseudomallei, B. anthracis and F. tularensis antibodies in infected patients, and infected or vaccinated animals. These antibodies were absent in the sera of naïve test subjects. The advantages of the carbohydrate microarray technology over the traditional indirect hemagglutination and microagglutination tests for the serodiagnosis of melioidosis and tularemia are discussed. Furthermore, this array is a multiplex carbohydrate microarray for the detection of all three biothreat bacterial infections including melioidosis, anthrax and tularemia with one, multivalent device. The implication is that this technology could be expanded to include a wide array of infectious and biothreat agents.
Asunto(s)
Anticuerpos Antibacterianos/análisis , Bacillus anthracis/inmunología , Burkholderia pseudomallei/inmunología , Carbohidratos/química , Francisella tularensis/inmunología , Análisis por Micromatrices/métodos , Anticuerpos Antibacterianos/inmunología , Bacillus anthracis/química , Burkholderia pseudomallei/química , Francisella tularensis/químicaRESUMEN
A whole-body mouse model of pneumonic melioidosis was established for future evaluation of biodefense vaccine candidates. The aerosol 50% lethal doses of Burkholderia pseudomallei strain 1026b for BALB/c and C57BL/6 mice and the times to death, dissemination in organs, and tissue loads after exposure of the mice to low- and high-dose aerosols are reported. In addition, rpsL mutant backgrounds were attenuated in this acute model of disease.
Asunto(s)
Bioterrorismo/prevención & control , Burkholderia pseudomallei/patogenicidad , Modelos Animales de Enfermedad , Melioidosis/patología , Neumonía Bacteriana/patología , Animales , Humanos , Melioidosis/microbiología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Neumonía Bacteriana/microbiología , Proteínas Ribosómicas/genética , VirulenciaRESUMEN
In vitro susceptibilities to 28 antibiotics were determined for 11 strains of Burkholderia mallei by the broth microdilution method. The B. mallei strains demonstrated susceptibility to aminoglycosides, macrolides, quinolones, doxycycline, piperacillin, ceftazidime, and imipenem. For comparison and evaluation, 17 antibiotic susceptibilities were also determined by the E-test. E-test values were always lower than the broth dilution values. Establishing and comparing antibiotic susceptibilities of specific B. mallei strains will provide reference information for assessing new antibiotic agents.
Asunto(s)
Antibacterianos/farmacología , Burkholderia/efectos de los fármacos , Muermo/microbiología , Burkholderia/aislamiento & purificación , Infecciones por Burkholderia/microbiología , Medios de Cultivo/farmacología , Humanos , Pruebas de Sensibilidad Microbiana/métodosRESUMEN
Little is known about the virulence factors of Burkholderia mallei, the etiologic agent of glanders. We employed subtractive hybridization to identify genetic determinants present in B. mallei but not in Burkholderia thailandensis, a non-pathogenic soil microbe. Three subtractive hybridization products were mapped to a genetic locus encoding proteins involved in the biosynthesis, export and translocation of a capsular polysaccharide. We identified an insertion sequence (IS 407 A) at one end of the capsule gene cluster and demonstrated that it was functional in B. mallei. Mutations were introduced in the B. mallei capsular gene cluster and the corresponding mutants were examined for their reactivity with antibodies raised against Burkholderia pseudomallei surface polysaccharides by immunoblotting and ELISA. Immunogold electron microscopy demonstrated the presence of a capsule on the surface of B. mallei ATCC 23344 (parental strain) but not on B. mallei DD3008 (capsule mutant) or B. thailandensis. Surprisingly, B. thailandensis also harboured a portion of the capsule gene cluster. ATCC 23344 was highly virulent in hamsters and mice, but DD3008 was avirulent in both animal models. The results presented here demonstrate that the capsular polysaccharide of B. mallei is required for production of disease in two animal models of glanders infection and is a major virulence factor.
Asunto(s)
Cápsulas Bacterianas/genética , Burkholderia/patogenicidad , Genes Bacterianos , Polisacáridos Bacterianos/genética , Secuencia de Aminoácidos , Animales , Cápsulas Bacterianas/análisis , Cápsulas Bacterianas/química , Composición de Base , Secuencia de Bases , Burkholderia/química , Burkholderia/genética , Clonación Molecular , Cricetinae , Elementos Transponibles de ADN , Modelos Animales de Enfermedad , Femenino , Genoma Bacteriano , Melioidosis/microbiología , Ratones , Ratones Endogámicos BALB C , Microscopía Inmunoelectrónica , Datos de Secuencia Molecular , Familia de Multigenes , Mutación , Hibridación de Ácido Nucleico , Polisacáridos Bacterianos/análisis , Alineación de Secuencia , VirulenciaRESUMEN
Sixty male BALB/c mice were inoculated intraperitoneally with either a sublethal or a lethal dose of Burkholderia mallei China 7 strain, then killed at multiple time points postinoculation. Histopathologic changes were qualitatively similar in both groups and consisted of pyogranulomatous inflammation. In sublethal study mice, changes were first seen at 6 hours in mediastinal lymph nodes, then in spleen, liver, peripheral lymph nodes, and bone marrow at day 3. These changes generally reached maximal incidence and severity by day 4 but decreased by comparison in all tissues except the liver. Changes were first seen in lethal study mice also at 6 hours in mediastinal lymph nodes and in spleens. At day 1, changes were present in liver, peripheral lymph nodes, and bone marrow. The incidence and severity of these changes were maximal at day 2. In contrast to sublethal study mice, the incidence and severity of the changes did not decrease through the remainder of the study. The most significant difference between the two groups was the rapid involvement of the spleen in the lethal study mice. Changes indicative of impaired vascular perfusion were more frequently seen in the sublethal study mice. Our findings indicate that mice are susceptible to B. mallei infection and may serve as an appropriate model for glanders infection in a resistant host such as human beings. Additionally, by immunoelectron microscopy, we showed the presence of type I O-antigenic polysaccharide (capsular) antigen surrounding B. mallei.
Asunto(s)
Infecciones por Burkholderia/veterinaria , Modelos Animales de Enfermedad , Muermo/fisiopatología , Animales , Burkholderia/ultraestructura , Infecciones por Burkholderia/fisiopatología , Recuento de Colonia Microbiana/veterinaria , Muermo/microbiología , Inmunohistoquímica/veterinaria , Inyecciones Intraperitoneales/veterinaria , Masculino , Ratones , Ratones Endogámicos BALB C , Microscopía Inmunoelectrónica/veterinaria , Distribución Aleatoria , Organismos Libres de Patógenos EspecíficosRESUMEN
BACKGROUND AND PURPOSE: The Coxiella burnetii phase-I cellular vaccine is efficacious in humans, imparting nearly complete protection against Q fever. However, this vaccine can also induce sterile abscesses and granulomas at the inoculation site in humans previously sensitized by natural infection or vaccination. To decrease the possibility of vaccinating immune persons, vaccinees are currently screened by skin testing to detect pre-existing Q fever immunity. We developed a model of abscess hypersensitivity in Hartley guinea pigs to assess the likelihood that Q fever vaccines would induce adverse vaccination reactions in previously sensitized individuals. METHODS: Guinea pigs (4 to 6/group) were sensitized to C. burnetii by immunization and aerosol challenge, or by intraperitoneal inoculation. Eight weeks later, animals were then vaccinated SC with a Q fever cellular (WCI) or chloroform:methanol residue (CMR) vaccine. Development of adverse reactions at the vaccination site was assessed histologically and by observation of increases in erythema and/or induration. RESULTS: The WCI vaccine caused greater magnitude and duration of erythema and induration at the vaccination sites than did the CMR vaccine. In addition, non-immune guinea pigs developed induration when given WCI, but not CMR vaccine. CONCLUSIONS: The CMR vaccine may prove a safe alternative to WCI vaccines for use in individuals unscreened for prior immunity to C. burnetii.
Asunto(s)
Absceso/inmunología , Vacunas Bacterianas/efectos adversos , Coxiella burnetii/inmunología , Hipersensibilidad , Modelos Animales , Fiebre Q/prevención & control , Absceso/patología , Aerosoles , Animales , Cloroformo , Eritema/inmunología , Femenino , Cobayas , Humanos , Hipersensibilidad/patología , Masculino , Metanol , Piel/patología , VacunaciónRESUMEN
OBJECTIVE: To determine whether transdiaphragmatic transport in hamsters is similar to that described in other animals by examining transport of an intraperitoneally administered marker. METHODS: Monastral blue B suspension was administered intraperitoneally to 28 male Syrian hamsters (Mesocricetus auratus). Four hamsters each were euthanized 7, 15, and 30 min, and 1, 2, 3, and 24 h later. Specimens were examined microscopically for presence of marker. RESULTS: Marker was present in intrathoracic lymphatic vessels and cranial and caudal mediastinal lymph nodes by 7 min after its administration. The amount of marker in lymph nodes increased with time. The subcapsular distribution of marker was consistent with lymphatic transport. By 1 h after its administration, marker was present in the liver, spleen, bone marrow, and mesenteric and mandibular lymph nodes. Patterns of marker distribution in these tissues were consistent with hematogenous transport, but the amount of marker was considerably less than that in the intrathoracic lymph nodes at corresponding times. CONCLUSIONS: Particulates were most likely translocated from the hamster peritoneal cavity to intrathoracic lymph nodes via transdiaphragmatic lymphatic vessels. A portion of the translocated particulates entered the blood, where they were distributed to a variety of tissues within a short time.
Asunto(s)
Colorantes/metabolismo , Diafragma/metabolismo , Indoles/metabolismo , Sistema Linfático/metabolismo , Mesocricetus/metabolismo , Compuestos Organometálicos/metabolismo , Animales , Transporte Biológico , Médula Ósea/metabolismo , Cricetinae , Epidídimo/metabolismo , Cinética , Hígado/metabolismo , Ganglios Linfáticos/metabolismo , Masculino , Peritoneo/metabolismo , Bazo/metabolismo , Testículo/metabolismoRESUMEN
Thirty-one female Syrian hamsters (Mesocricetus auratus) were inoculated intraperitoneally with a lethal dose of Burkholderia mallei (Budapest strain). Hamsters were killed postinoculation on days 0 through 6. Lesions were first noted in the spleens on postinoculation day 1, and in mediastinal and mesenteric lymph nodes, mediastinum, liver, and bone marrow on day 2. Lesions were present in the lung and submandibular lymph nodes on day 3, and in the brain on day 5. The characteristic histopathologic change was necrotizing pyogranulomatous inflammation, often with hemorrhage. Lesions indicative of impaired vascular perfusion, such as ischemia and infarction, were evident at the later time points. Pathologic changes generally increased in severity and distribution with time, and almost all tissues were ultimately affected. Our findings suggest that intraperitoneal bacteria were rapidly transported to mediastinal lymph nodes by transdiaphragmatic lymphatics and ultimately seeded other tissues hematogenously. The results of the study indicate that the Syrian hamster is a useful small animal model for glanders.
Asunto(s)
Burkholderia , Muermo/patología , Animales , Cricetinae , Femenino , Inmunohistoquímica , Inyecciones Intraperitoneales , Mesocricetus , Microscopía Electrónica , Bazo/patologíaRESUMEN
BACKGROUND AND PURPOSE: Q fever is a disease of humans. Vaccines to prevent this disease have demonstrated efficacy in rodents and must also be evaluated for efficacy in a nonhuman primate model. Preliminary to vaccine efficacy experiments, cynomolgus and rhesus monkeys were evaluated as suitable experimental models of acute Q fever. METHODS: Both species of monkeys were challenged with aerosolized 10(5) virulent phase-I Coxiella burnetii Henzerling strain, and clinical and serologic responses were determined. RESULTS: Radiographic changes were observed in seven of eight monkeys of both species; however, changes in cynomolgus monkeys tended to be more significant. Between 7 and 10 days after challenge, all rhesus monkeys and 88% of cynomolgus monkeys were bacteremic. Sequential increases in antibody responses to C. burnetii phase-I and phase-II whole cells and phase-I lipopolysaccharide were observed in both species. Although the maximal rectal temperature increase was similar in both species, duration of fever was slightly longer in rhesus monkeys. Clinical features were similar to those described in human acute Q fever patients. CONCLUSIONS: On the basis of the more pronounced radiographic changes in cynomolgus monkeys, we favor use of this species for future studies of vaccine efficacy.
Asunto(s)
Coxiella burnetii/patogenicidad , Modelos Animales de Enfermedad , Macaca fascicularis/microbiología , Macaca mulatta/microbiología , Enfermedades de los Monos/microbiología , Fiebre Q/veterinaria , Enfermedad Aguda , Aerosoles , Animales , Anticuerpos Antibacterianos/análisis , Antígenos Bacterianos/inmunología , Temperatura Corporal , Coxiella burnetii/inmunología , Estudios de Evaluación como Asunto , Femenino , Humanos , Pulmón/diagnóstico por imagen , Pulmón/patología , Enfermedades Pulmonares Intersticiales/diagnóstico , Enfermedades Pulmonares Intersticiales/inmunología , Enfermedades Pulmonares Intersticiales/microbiología , Enfermedades Pulmonares Intersticiales/veterinaria , Masculino , Ratones , Enfermedades de los Monos/diagnóstico , Enfermedades de los Monos/inmunología , Fiebre Q/diagnóstico , Fiebre Q/inmunología , Fiebre Q/microbiología , Radiografía , Pruebas Serológicas/veterinariaRESUMEN
Coxiella burnetii phase I whole cell vaccine (WCV) is associated with risk of severe local delayed-type hypersensitivity (DTH) reactions in previously immunized individuals or those sensitized by natural exposure. We compared this vaccine to another investigational vaccine derived by chloroform-methanol extraction of phase I whole cells (chloroform-methanol residue vaccine, CMRV). Hairless guinea pigs, sensitized with either WCV or CMRV, were given 60,600 and 6,000 ng of WCV or CMRV in an intradermal (i.d.) skin test. The i.d. administration of WCV consistently caused more host reactions than comparable doses of CMRV in guinea pigs sensitized with either WCW or CMRV, suggesting that CMRV may be a safer vaccine. However, the CMRV was not innocuous and caused significant indurated lesions and micro-abscesses at the 600 ng and 6,000 ng skin test sites.
Asunto(s)
Antígenos Bacterianos/inmunología , Vacunas Bacterianas/inmunología , Vacunas Bacterianas/toxicidad , Coxiella burnetii/inmunología , Hipersensibilidad Tardía/etiología , Animales , Antígenos Bacterianos/administración & dosificación , Antígenos Bacterianos/toxicidad , Vacunas Bacterianas/administración & dosificación , Cloroformo , Femenino , Cobayas , Hipersensibilidad Tardía/patología , Inyecciones Intradérmicas , Metanol , Piel/patología , Pruebas Cutáneas , VacunaciónRESUMEN
A case of Q fever in a sheep producer was detected by a surveillance system in North Dakota in 1993, when Q fever was not reportable. This is the first officially documented case in the state. To estimate the prevalence of Coxiella burnetii infection and identify associated risk factors, we conducted a study covering the whole state. A total of 17 cases were identified among 496 sheep producers, their family members, and hired helpers. The number of sheep raised was a good predictor of C. burnetii infection. Lambing outdoors and frequent physical contacts with sheep during lambing were associated with a higher risk, but petting dogs was correlated with a lower risk. We conclude that C. burnetii infection is prevalent among sheep producers in North Dakota. As the result, Q fever became a reportable disease in North Dakota.
Asunto(s)
Enfermedades de los Trabajadores Agrícolas/epidemiología , Crianza de Animales Domésticos/estadística & datos numéricos , Fiebre Q/epidemiología , Ovinos , Adulto , Distribución por Edad , Anciano , Animales , Femenino , Humanos , Masculino , Persona de Mediana Edad , North Dakota/epidemiología , Prevalencia , Factores de Riesgo , Estudios Seroepidemiológicos , Distribución por Sexo , Encuestas y CuestionariosRESUMEN
The authors examined the efficacy of Bacillus anthracis protective antigen (PA) combined with adjuvants as vaccines against an aerosol challenge of virulent anthrax spores in rhesus macaques. Adjuvants tested included i) aluminum hydroxide (Alhydrogel), ii) saponin QS-21 and iii) monophosphoryl lipid A (MPL) in squalene/lecithin/Tween 80 emulsion (SLT). Animals were immunized once with either 50 micrograms of recombinant PA plus adjuvant, or with Anthrax Vaccine Adsorbed (AVA), the licensed human anthrax vaccine. The serological response to PA was measured by enzyme linked immunosorbent assay. Lymphocyte proliferation and serum neutralization of in vitro lethal toxin cytotoxicity were also assayed. In all vaccine groups, anti-PA IgM and IgG titers peaked at 2 weeks and 4-5 weeks postimmunization, respectively. Five weeks postimmunization, animals in all vaccine groups demonstrated PA-specific lymphocyte proliferation and sera that neutralized in vitro cytotoxicity. Six weeks after immunization, the animals were challenged by aerosol with approximately 93 LD50 of virulent anthrax spores. Animals were bled daily for 1 week to monitor bacteremia, and deaths were recorded. Anti-PA ELISA titers in all groups of immunized animals were substantially increased 2 weeks after challenge. One dose of each vaccine provided significant protection (> 90%) against inhalation anthrax in the rhesus macaques.
Asunto(s)
Carbunco/prevención & control , Vacunas Bacterianas , Administración por Inhalación , Aerosoles , Animales , Reacciones Antígeno-Anticuerpo , Modelos Animales de Enfermedad , Ensayo de Inmunoadsorción Enzimática , Femenino , Macaca mulatta , Masculino , Pruebas Serológicas , Resultado del TratamientoRESUMEN
Q fever is an acute and self-limited febrile illness caused by the obligate intracellular bacterium Coxiella burnetii. While phase I cellular Q fever vaccines are efficacious in humans, vaccination of immune individuals may result in sterile abscesses and granulomas. The chloroform:methanol residue vaccine (CMR) was developed as a safer alternative. The efficacy of a licensed phase I cellular vaccine (Q-Vax) was compared with that of CMR vaccine in A/J mice and Hartley guinea pigs challenged with virulent phase I C. burnetii by aerosol. Both vaccines were efficacious. The CMR vaccine dose required to protect 50% of mice (PD50) against lethal aerosol challenge (11 LD50) was one-third of the Q-Vax dose. However, the PD50 for CMR was four times the Q-Vax dose in guinea pigs challenged by aerosol (60 LD50). It was concluded that CMR is an efficacious alternative to cellular Q fever vaccines for the prevention of Q fever.
Asunto(s)
Vacunas Bacterianas/uso terapéutico , Coxiella burnetii/inmunología , Fiebre Q/prevención & control , Aerosoles , Animales , Vacunas Bacterianas/administración & dosificación , Cloroformo/química , Modelos Animales de Enfermedad , Femenino , Cobayas , Masculino , Metanol/química , Ratones , Ratones Endogámicos ARESUMEN
Lymphoid cell phenotypes within the spleen and thymus were analyzed to determine whether numerical or proportional changes in cell populations could account for the immunosuppression seen after vaccination of mice with inactivated phase I Coxiella burnetii whole-cell vaccine (WCI). Within 21 days of vaccination with WCI, there was a reduction in the percentage of splenic T cells and B cells while the numbers of thymic T cells and B cells increased. A substantial percentage of spleen cells did not bear typical T cell or B cell surface markers. In contrast, except for an early rise (by day 3) in the numbers of T and B cells, injecting the chloroform-methanol residue subunit-vaccine (CMR) caused no significant phenotypic changes of lymphoid cells in the spleen or thymus. The percentage of thymus cells bearing T cell phenotypes was similar in mice vaccinated with WCI or CMR. However, the total number of T cells in the thymus dramatically decreased in mice vaccinated with WCI. There was no correlation between the lymphocyte hyporesponsiveness to mitogens and WCI in vitro and the increased numbers of CD8-positive splenocytes. These results suggest that WCI vaccination caused dramatic changes in splenocyte and thymocyte lymphocyte populations and provide evidence for the more benign nature of the CMR vaccine.
Asunto(s)
Linfocitos B/inmunología , Vacunas Bacterianas/inmunología , Cloroformo/farmacología , Coxiella burnetii/inmunología , Metanol/farmacología , Bazo/inmunología , Linfocitos T/inmunología , Animales , Anticuerpos Antibacterianos/sangre , Biomarcadores , Recuento de Células , Coxiella burnetii/efectos de los fármacos , Femenino , Linfocitos/inmunología , Ratones , Ratones Endogámicos C57BL , Fenotipo , Bazo/citología , Timo/citología , Timo/inmunologíaRESUMEN
A new lot of Francisella tularensis live vaccine strain (LVS) was tested for immunogenicity in 19 human volunteers. Scarification vaccination induced specific cell-mediated and humoral immune responses. We noted a significant rise in antibodies against irradiation-killed LVS, formalin-killed virulent strain SCHU4, and an ether extracted antigen preparation (EEx) beginning 14 days after vaccination. A main target of the humoral immune response was lipopolysaccharide. Eighty percent of vaccinated volunteers developed a positive IgG response to EEx by day 14 and 100% of vaccinees responded positively by day 21. Background IgA titers were lower than corresponding IgG or IgM titers. No early IgM rise was noted with any antigen. By day 14 after vaccination, in vitro lymphocyte responses to LVS, the rough variant of LVS, and EEx were significantly increased compared to controls. Seventy percent of volunteers had a positive in vitro lymphocyte response to EEx within 14 days of vaccination. We predict that EEx will be a useful antigen for diagnosing tularemia and for evaluating the immunogenicity of vaccines against tularemia. We are testing this antigen using sera from human cases of tularemia and control sera.
Asunto(s)
Anticuerpos Antibacterianos/biosíntesis , Vacunas Bacterianas/inmunología , Francisella tularensis/inmunología , Anticuerpos Antibacterianos/sangre , Humanos , Inmunidad Celular/inmunología , Lipopolisacáridos/inmunología , Activación de Linfocitos/inmunología , Tularemia/diagnósticoRESUMEN
Modulation of the immune response by the chloroform-methanol residue (CMR) of phase I Coxiella burnetii whole cell was studied in Rift Valley fever virus-infected, or in naive endotoxin-non-responder C3H/HeJ mice. A single dose of CMR completely protected the mice from viral infection. Treating virus-infected mice with antibodies directed against interferons alpha/beta (IFN-alpha beta) and gamma (IFN-gamma) eliminated the CMR-induced protection. CMR stimulated the production of high levels of IFN-alpha/beta and 2'-5'-oligoadenylate synthetase activities in sera of the CMR-treated mice. IFN-gamma was present in supernatants of cultured spleen cells of CMR-treated, virus-infected mice, but not in their serum. Priming mice with CMR optimized the release of INF-gamma, interleukin-1 alpha (IL-1 alpha) and IL-6 from splenocytes in vitro. When stimulated in vitro, IL-2 and granulocyte-macrophage stimulating factor (GM-CSF) did not require in vivo priming for release from cultured spleen cells. Fluorescence-assisted cytometry of CMR-treated mouse spleen cells showed there was a CMR-dependent increase in the percentage of T-cells and Ia-positive T-cells. There also was a biphasic increase in the ratio between Th (L3T4) and Ts (Lyt2) cells. Biological activities stimulated by CMR indicate that CMR is a potent immunostimulant, which may modulate specific and non-specific antiviral responses.
Asunto(s)
Formación de Anticuerpos , Antígenos Bacterianos/inmunología , Coxiella burnetii/inmunología , Inmunidad Celular , Fiebre del Valle del Rift/inmunología , 2',5'-Oligoadenilato Sintetasa/metabolismo , Animales , Anticuerpos Antivirales/inmunología , Biomarcadores , Células Cultivadas , Cloroformo , Citocinas/biosíntesis , Femenino , Interferones/biosíntesis , Masculino , Metanol , Ratones , Ratones Endogámicos C3H , Bazo/citología , Bazo/inmunologíaRESUMEN
Strains of Coxiella burnetii phase I and II whole cells (WC-I and WC-II) or whole cell fractions were assessed for their potential to induce long-lasting protection in endotoxin-non-responder C3H/HeJ or CD-1 mice against Rift Valley fever (RVF) virus challenge. Among the whole cell fractions, only the chloroform-methanol residue (CMR), administered as a single dose (100 micrograms per mouse) 24 h before viral challenge, effectively protected 100% of the mice from RVF virus; the CMR of the Ohio strain of C. burnetii was not protective. Most of the RVF virus-infected mice treated with other C. burnetii cell fractions died, although their times to death varied. Lipopolysaccharide (LPS) associated with CMR preparations used in these studies, did not protect against RVF virus challenge. A single dose of 100 micrograms of CMR given 24 h before viral challenge completely eradicated 4-5 logs of RVF virus in the serum, liver, spleen, and central nervous system. Compared to several other immunomodulators, CMR was an equally effective antiviral agent. Efficacy of CMR of both Henzerling and Ohio strains disappeared or was marginal when treatment was initiated 2-3 days before RVF viral challenge, even when a second or a third dose of CMR was administered after challenge. A single dose of liposome-encapsulated CMR to RVF virus-infected mice extended the range of therapeutic efficacy of this biologically active component of C. burnetii to 4 days before infection.
Asunto(s)
Antivirales/farmacología , Coxiella burnetii/fisiología , Fiebre del Valle del Rift/prevención & control , Adyuvantes Inmunológicos/farmacología , Animales , Embrión de Pollo , Chlorocebus aethiops , Cloroformo , Coxiella burnetii/química , Coxiella burnetii/aislamiento & purificación , Femenino , Lipopolisacáridos/farmacología , Liposomas/metabolismo , Masculino , Metanol , Ratones , Ratones Endogámicos C3H , Virus de la Fiebre del Valle del Rift , Especificidad de la Especie , Células VeroRESUMEN
An enzyme immunoassay was validated for the serodiagnosis of acute Q fever. Minimum positive tests were determined for both serial dilutions and a single dilution of patient sera. To establish the specificity of the test, 152 serum samples were tested from individuals with no evidence of past Coxiella burnetii infection. Diagnostic titers were set at > or = 128 for the IgM and IgG responses to phase I, at > or = 512 for the IgM response to phase II and at > or = 1,024 for the IgG response to phase II Coxiella burnetii. These titers gave a false-positive rate of < or = 1%. Alternatively, testing a single dilution of sera (1:128) gave specificities ranging from 97.3 to 98.7%. Tests with the greatest sensitivities, using serially diluted early convalescent-phase sera, were the IgM (84%) and IgG (80%) responses to phase II Coxiella burnetii. At a single serum dilution, 92% of early convalescent sera had a positive IgG response to phase II Coxiella burnetii. With a high specificity and good sensitivity, the EIA can be used to diagnose acute Q fever with a single convalescent serum specimen. The duration of a positive response was greater than five years.
Asunto(s)
Coxiella burnetii/inmunología , Inmunoglobulinas/análisis , Fiebre Q/diagnóstico , Reacciones Falso Positivas , Humanos , Técnicas para Inmunoenzimas , Inmunoglobulina A/análisis , Inmunoglobulina G/análisis , Inmunoglobulina M/análisis , Fiebre Q/inmunología , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Pruebas SerológicasRESUMEN
The specific humoral and cell-mediated immune responses of human volunteers vaccinated with the Francisella tularensis live vaccine strain (LVS) were evaluated. In the search for an optimal antigen to measure the immunogenicity of the vaccine in an enzyme-linked immunosorbent assay, we tested irradiation-killed LVS, an aqueous ether extract of the LVS (EEx), lipopolysaccharide (LPS) from LVS, and a virulent strain (SCHU4). Volunteers were immunized with LVS by scarification. Immunoglobulin G (IgG) responses to LVS and LPS gave the highest background titers when tested with sera from unimmunized volunteers, whereas IgA, IgG, and IgM background titers to EEx and SCHU4 were low. Vaccination caused a significant rise (P < 0.01) in IgA, IgG, and IgM titers to all antigens tested, except for the IgG response to LPS. Eighty percent of vaccinated volunteers developed a positive IgG response to EEx 14 days postvaccination, while 50% were positive to LVS. By day 14 after vaccination, 70% of immunized volunteers exhibited a positive response to EEx in an in vitro peripheral blood lymphocyte proliferation assay. EEx, a specific and sensitive antigen for evaluating immune responses of vaccinated volunteers, may be a superior antigen for the diagnosis of tularemia.