RESUMEN
Introduction. Streptococcus pneumoniae is a significant bacterial pathogen in humans. Currently, there are two types of pneumococcal vaccines, but there are concerns regarding their application.Aim. Since many pneumococcal proteins are serotype-independent, polyhistidine triad protein D (PhtD) has been selected as a vaccine candidate.Methodology. We prepared recombinant PhtD and its C-terminal fragment (PhtD-C) using alum and outer-membrane vesicles (OMVs) as adjuvants. The combinations were injected intraperitoneally into mice, and then total immunoglobulin G (IgG) and specific IgG, IgG1 and IgG2a were measured. A serum bactericidal assay and opsonophagocytosis were also performed as complementary tests. Meningococcal OMVs were used as an adjuvant.Results. The levels of specific IgG and IgG1 against combinations of PhtD and its C-terminal with OMVs and alum as adjuvants increased at the time of the third mouse immunization on day 35. Forty per cent and 60% of S. pneumoniae ATCC 6303 (serotype 3) as a virulent pneumococcal strain, respectively, were killed in the opsonophagocytosis test and these results could also be observed in the serum bactericidal assay. Mice mmunized iwith PhtD and its C-terminal with OMVs and alum as adjuvants survived after 10 days of pneumococcal challenge.Conclusion. The combination of PhtD and PhtD-C with alum produced optimal results, but the combination of PhtD and PhtD-C with OMVs produced minimal results by comparison. The survival rates were also measured, and these corresponded with the results of the immunological assessments. Our findings showed that mice receiving PhtD and PhtD-C plus OMV and alum had higher survival rates than the mice in the other groups.
Asunto(s)
Anticuerpos Antibacterianos/sangre , Antígenos Bacterianos/inmunología , Proteínas Bacterianas/inmunología , Infecciones Neumocócicas/prevención & control , Vacunas Neumococicas/inmunología , Streptococcus pneumoniae/inmunología , Adyuvantes Inmunológicos/administración & dosificación , Animales , Femenino , Histidina/inmunología , Humanos , Inmunoglobulina G/sangre , Ratones , Ratones Endogámicos BALB C , Infecciones Neumocócicas/inmunología , Infecciones Neumocócicas/microbiología , Proteínas Recombinantes , VacunaciónRESUMEN
Neisseria meningitidis is one of the main causes of sepsis and meningitis, which are two serious life-threatening diseases in both children and adolescents. Porin A (porA) from both serogroup A and B were cloned into the pET28a plasmid and expressed in E. coli BL21 (DE3). The protein was expressed in Escherichia coli BL21 (DE3) and confirmed by SDS-PAGE and Western blot analysis. BALB/c mice were subcutaneously injected three times with 25 µg of the recombinant PorA. Specific total IgG antibodies and isotypes were evaluated using ELISA assay. Opsonophagocytic assay (OPA) and Serum Bactericidal assay (SBA) were performed. Results showed that vaccinated mice exhibited higher levels of anti-Porin A (p < 0.05) with a predominant IgG1 response compared to the control group. Results from in vitro experiments indicated that N. meningitidis was opsonized with immunized-mice sera, and compared to non-immunized mice, immunized mice displayed significantly increased phagocytic uptake and effective intracellular killing. In this study, serogroup B N. meningitidis OMV of strain CSBPI G-245 and complete and incomplete Freund's adjuvant were used. Results demonstrated that Porin A could be a valuable target for the development of immunotherapeutic strategies against N. meningitidis.
Asunto(s)
Adyuvantes Inmunológicos , Infecciones Meningocócicas/prevención & control , Vacunas Meningococicas/inmunología , Neisseria meningitidis Serogrupo A/inmunología , Neisseria meningitidis Serogrupo B/inmunología , Porinas/inmunología , Adyuvantes Farmacéuticos , Animales , Anticuerpos Antibacterianos/sangre , Antígenos Bacterianos/genética , Antígenos Bacterianos/inmunología , Estudios Transversales , Modelos Animales de Enfermedad , Escherichia coli/genética , Femenino , Adyuvante de Freund , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos/genética , Vectores Genéticos , Inmunización , Inmunoglobulina G/sangre , Inmunoterapia , Inyecciones Subcutáneas , Lípidos , Infecciones Meningocócicas/inmunología , Infecciones Meningocócicas/microbiología , Vacunas Meningococicas/genética , Ratones , Ratones Endogámicos BALB C , Porinas/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Determinación de Anticuerpos Séricos BactericidasRESUMEN
BACKGROUND: Stenotrophomonas maltophilia (S. maltophilia) is a multiple-antibiotic-resistant opportunistic pathogen that is being isolated with increasing frequency from patients with health-care-associated infections. S. maltophilia is inherently resistant to most of the available antimicrobial agents. Spread of resistant strains has been attributed, in part, to class I integrons. In vitro susceptibility studies have shown trimethoprim-sulfamethoxazole and new floroquinolones as two important agents with activity against these organisms. METHODS: 150 isolates of S. maltophilia were isolated from clinical samples such as respiratory discharges, sputum, and catheter and hospital environments. These isolates were also subjected to susceptibility testing and polymerase chain reaction for four groups of genes including int encoding integron elements, sulI and sulII encoding trimethoprim-sulfamethoxazole resistance and smqnr encoding quinolone resistance. RESULTS: The rate of resistance to trimethoprim-sulfamethoxazole was up to 27 (18%) and the highest resistance to quinolone family belonged to ofloxacin (20%) and the lowest rate was for gatifloxacin (16%). The results showed that 14% of isolates contained integron elements concomitantly with sulI and sulII genes. CONCLUSION: Resistance rate of S. maltophilia to co-trimoxazole and fluoroquinolones and detection of integron elements between isolates in this study showed that this rate corresponded to other data obtained from other studies.