Journal of immunological techniques in infectious diseases最新文献

Dendritic cells (DC) are important antigen-presenting cells that have abilities to induce and maintain T-cell immunity, or attenuate it during hyperimmunization. Additional activation of DCs may be useful for vaccination purposes. Imiquimod is known to be a specific agonist of the Toll-like receptors (TLR7), which are located mainly on DCs. To study the effect of DC stimulation on the effectiveness of an HIV-1 p55 gag DNA vaccine in a mice model, we employed 25, 50, and 100 nM of Imiquimod as an adjuvant. Subsequently, Western blot analysis was used to quantify p55 protein production after the immunization. To characterize T-cells immune response, both the frequency of IFN-γ -secreting cells and IFN-γ and IL-4 production were measured, via an ELIspot assay and ELISA, respectively. Low concentrations of Imiquimod were found to effectively stimulate Gag production and the magnitude of the T-cell immune response, whereas higher concentrations reduced vaccination effects. Our results show that the adjuvant effects of Imiquimod depend on concentration. The use of Imiquimod may be helpful to study DC to T cell communication, including possible induction of immunotolerance.

Objective: Rotavirus (RV) is the most common cause of severe dehydrating diarrhoea in healthy infants and young children. The aims of this study were to investigate a RV outbreak in the pediatric hematology and oncology ward and to examine possible associations between immune status and RV infection.

Patients and methods: Twenty-eight children (19 boys and 9 girls) who were hospitalized for treatment of hematological malignancy and solid organ tumor during the RV outbreak were enrolled in this study. Fourteen of the 28 patients developed RV gastroenteritis (GE) during the observation period. RV antigen and RV IgG and IgA were measured by enzyme-linked immunosorbent assays. RV G and P types were determined by reverse transcriptase-polymerase chain reaction.

Results: Mean duration of RVGE in 14 patients was 13.9 days and mean severity score was 7.4. Two RV strains (G3P [8] and G2P [4]) were mainly circulating in the ward, which might result in the formation of a reassortant G2P [8] strain and mixed infection with G2+3P [8] in the immunocompromised patients. RV antigenemia was detected in 22 of the 28 patients (78.6%). RV-specific IgG titers in acute-phase sera of RVGE group were significantly lower than those in non-RVGE group (P=0.001). Mean age of the patients was significantly lower in RVGE group (5.5 ± 4.6 years) than non RVGE group (10.6 ± 4.5 years) (P=0.015).

Conclusion: Our data demonstrate that host factors including age, underlying diseases, and immune status may be associated with the susceptibility of RV infection in immunocompromised patients at the time of the nosocomial infection.

Background: Influenza vaccination coverage in the US is lower than the recommended Healthy People 2020 threshold, especially among older African Americans. This analysis explores the complex relationship among neighborhood-level factors, socio behavioral influences, and influenza vaccination outcomes among older African Americans.

Methods: We analyzed data from 221 Black/African American participants' age ≥50 years living in Atlanta, Georgia. Generalized Estimating Equations for linear and logistic models assessed associations among socio demographic factors, census-tract neighborhood characteristics, and reported 2012-2013 seasonal influenza vaccination receipt, controlling for correlations among individuals within the same census tracts. Evaluated environmental factors included neighborhood deprivation indicators such as vacant housing percentage, vehicle availability, area violent crimes, and racial/ethnic composition.

Results: Reported greater influenza immunization uptake was significantly associated with older age ≥65 years [OR=1.05, p=0.04], positive vaccination attitudes [OR=5.30, p<0.01], having health insurance [OR=14.37, p=0.03], lower perceived neighborhood security [OR=0.51, p=0.02], and lower neighborhood vehicle ownership [OR=1.07, p=0.04], a proxy for neighborhood affluence and transportation ease. Having a post-secondary education was significantly associated with both positive perceived neighborhood security [β=0.28, p=0.02] and positive vaccination attitudes [β=0.27, p=0.02].

Conclusion: The findings provide evidence for distal neighborhood-level influences on influenza vaccination uptake among older African Americans. Lower vehicle ownership and lower perceived neighborhood security influenced seasonal influenza immunizations. Those who perceived personal risk, based on reported neighborhood security, displayed intent to obtain the seasonal influenza vaccine. Further investigation of multilevel, socio geographic factors is therefore warranted to more effectively address suboptimal influenza vaccine coverage among this population.

Neutrophils (PMNs) are recruited in high numbers to sites of host infection by the protozoan parasites of the genus Leishmania. Although PMNs are capable of phagocytizing Leishmania parasites and are potent producers of anti-microbial compounds including reactive oxygen species (ROS), they are unable to control the establishment of infection. Prior studies document production of ROS in isolated PMNs incubated with Leishmania under conditions allowing phagocytosis, but without a measure of single cells' responses it cannot be discerned whether PMN activation and ROS production is suppressed or ineffective in the cells that internalize the parasite. To address these interactions, we engineered a strain of fluorescent, mCherry-expressing Leishmania infantum (mCherry-Li). By infecting isolated human PMNs in vitro with mCherry-Li, we observed ready association of the parasites with PMNs in a time- and dose-dependent fashion. We also examined production of PMN ROS (using the fluorescent compound DHR123) and PMN activation (as evidence by loss of surface CD62L expression). Whereas many Li-associated (mCherry⁺) PMNs responded to parasite interactions and uptake with ROS production and/or activation, a proportion exhibited neither response. Furthermore, a large proportion of mCherry - "bystander" PMNs displayed both ROS production and activation. The heterogeneous response of PMNs to Leishmania exposure leads us to hypothesize, first, that some PMNs exhibit decreased activation upon phagocytosis of Leishmania, and could support their maintenance. Second, responses of bystander PMNs may contribute to a local inflammatory environment that is ineffective at parasite clearance.

Background: Self-sampling for Human Papillomavirus (HPV) testing may offer improved patient acceptability, decreased cost, and greater practicality than clinician collection of specimens. HPV testing among adolescents is necessary to conduct vaccine surveillance and may play a role in cervical cancer screening among some populations.

Methods: A cross-sectional prevalence study was conducted to compare the results of self-collected and clinician-collected specimens for Human papillomavirus (HPV) testing among South African adolescent females. All participants provided self-sampled vaginal swabs and underwent clinician-collection of cervical swabs for HPV DNA analysis. The level of agreement between HPV DNA results from the two specimen collection methods was measured.

Results: The level of agreement between HPV DNA results from self-collected and clinician-collected specimens was high (κ=86.7; p<0.001). A high prevalence of HPV overall was found by both specimen collection methods (57%; 95% CI 0.37-0.75). Low-risk HPV (LR-HPV) types were found slightly more frequently in self-collected specimens.

Conclusion: There is a high level of agreement between the HPV DNA results from self-collected and clinician-collected specimens. Self-collection of specimens for HPV testing is a viable alternative among adolescents.

Background: The epidemiology and impact of multiple concurrent Human papillomavirus (HPV) infections on the natural history of cervical disease is uncertain, but could have significant implications for cervical cancer prevention and HPV vaccination strategies.

Methods: A cross-sectional prevalence study was conducted to determine the overall prevalence of HPV and the rate of multiple concurrent HPV infections, in a cohort of sexually active HIV-uninfected South African adolescents. HPV genotyping was performed using the polymerase chain reaction.

Results: Overall prevalence of HPV was 64.1%. Multiple concurrent HPV infections were found in 43.6% of participants and 68% of HPV-infected participants. Non-vaccine high-risk HPV (HR-HPV) genotypes were found much more often than vaccine types (HPV16 and HPV18).

Conclusions: Our cohort of young South African females was found to have a high overall prevalence of HPV and multiple concurrent HPV infections. Most HR-HPV infections found were genotypes other than HPV16 or HPV18.