Uninfected Individuals (uninfected + individual)

Distribution by Scientific Domains

Selected Abstracts

Effects of Ligula intestinalis on habitat use, predation risk and catchability in European minnows

J. Museth
The frequency of infection with Ligula intestinalis (Cestoda) in European minnow Phoxinus phoxinus, in a subalpine lake in Eastern Norway, did not differ between vegetated shoreline, exposed shoreline and non-vegetated localities >50 m from the shoreline. There was no difference in the vertical distribution of infected and uninfected individuals. The frequency of infection was higher among minnows in brown trout Salmo trutta stomachs than among those obtained by gillnets and minnow traps, suggesting that brown trout selectively preyed on infected minnows. Prevalence of infection decreased with increasing fish size, probably due to selective mortality among parasitized individuals. Within a given length-class, minnows captured by different sections of multi-mesh gillnets showed a significant increase in the frequency of infection with increasing mesh-size. Apparently, parasitized individuals had a higher catchability in gillnets due to increased girth caused by the plerocercoid in the body cavity. This may partly explain why the observed prevalence of infection was several times higher among minnows captured by gillnets than by minnow traps. [source]

Monocyte-derived dendritic cells from HCV-infected patients transduced with an adenovirus expressing NS3 are functional when stimulated with the TLR3 ligand poly(I:C)

I. Echeverrķa
Summary., Dendritic cells (DC) transfected with an adenovirus encoding hepatitis C virus (HCV) NS3 protein (AdNS3) induce potent antiviral immune responses when used to immunize mice. However, in HCV infected patients, controversial results have been reported regarding the functional properties of monocyte-derived DC (MoDC), a cell population commonly used in DC vaccination protocols. Thus, with the aim of future vaccination studies we decided to characterize MoDC from HCV patients transfected with AdNS3 and stimulated with the TLR3 ligand poly(I:C). Phenotypic and functional properties of these cells were compared with those from MoDC obtained from uninfected individuals. PCR analysis showed that HCV RNA was negative in MoDC from patients after the culture period. Also, phenotypic analysis of these cells showed lower expression of CD80, CD86, and CD40, but similar expression of HLA-DR molecules as compared to MoDC from uninfected individuals. Functional assays of MoDC obtained from patients and controls showed a similar ability to activate allogeneic lymphocytes or to produce IL-12 and IL-10, although lower IFN-, levels were produced by cells from HCV patients after poly(I:C) stimulation. Moreover, both groups of MoDC induced similar profiles of IFN-, and IL-5 after stimulation of allogeneic T-cells. Finally, migration assays did not reveal any difference in their ability to respond to CCL21 chemokine. In conclusion, MoDC from HCV patients are functional after transduction with AdNS3 and stimulation with poly(I:C). These findings suggest that these cells may be useful for therapeutic vaccination in chronic HCV infection. [source]

The effects of human herpesvirus 8 infection and interferon-, response in cutaneous lesions of Kaposi sarcoma differ among human immunodeficiency virus-infected and uninfected individuals

F. Guedes
Summary Background, Kaposi sarcoma (KS) is associated with human herpesvirus 8 (HHV-8). The cutaneous immune response in this tumour is not well established and a better understanding is necessary. Objectives, To evaluate the HHV-8 expression and immune response in cutaneous lesions of classic KS (CKS) and AIDS-associated KS (AIDS-KS). Methods, We performed a quantitative immunohistochemical study of cells expressing HHV-8 latency-associated nuclear antigen (LANA), CD4, CD8 and interferon (IFN)-, in skin lesions from patients with CKS and AIDS-KS (with or without highly active antiretroviral therapy, HAART). Results, CKS showed higher LANA expression compared with AIDS-KS, regardless of HAART. We also found higher LANA expression in nodules compared with patch/plaque lesions. The tissue CD4+ cell proportion was lower in AIDS-KS patients without HAART than in patients with CKS. In CKS lesions, CD4+ and CD8+ cells expressed IFN-,, as shown by double immunostaining. AIDS-KS presented low numbers of IFN-,-expressing cells. CD8+ cell numbers were similar in all groups, which appeared unrelated to the clinical or epidemiological type of KS. Conclusions, Our quantitative data on the pattern of KS lesions in selected groups of patients, as shown by in situ immune response, demonstrated a CD4+ T-cell involvement associated with IFN-,, an environment of immune response-modified human immunodeficiency virus (HIV) infection. In our sample, the promotion of KS in patients without HIV appears to be related to higher HHV-8 load or virulence than in those with AIDS. This higher resistance may be explained by a sustained immune response against this herpesvirus, that is only partially restored but effective after HAART. [source]

Interleukin 12B gene polymorphism and apparent resistance to hepatitis C virus infection

D. Hegazy
Summary Cellular immunity with interferon gamma production could have a role in protection from hepatitis C virus (HCV). Interleukin (IL)-12 is a key cytokine in promoting such anti-viral T helper 1 (Th1) responses. We hypothesized that a genetic background able to promote cellular responses may be associated with apparent protection from infection and have investigated the distribution of the functional 1188A/C polymorphism of IL-12B in HCV exposed but uninfected cases. The frequency of the high IL-12-producing C allele was determined by restriction enzyme genotyping in 76 exposed,uninfected individuals and 105 healthy controls. Overall, the C allele was found in 27·6% of exposed,uninfected cases compared with 16·7% of healthy controls [,2 = 6·3, P = 0·02, odds ratio (OR) = 1·9, 95% confidence interval (CI) = 1·1,3·2]. CC genotype was found in 10·5% of exposed,uninfected cases compared with 0·9% controls (,2 = 9·3, P = 0·01, OR = 12, 95% CI = 1·5,100). Individuals at high risk of HCV infection yet who remain uninfected may be resistant in some way to infection. In our cohort of exposed,uninfected cases a genetic background of enhanced IL-12 production was associated with apparent resistance to HCV infection. This lends support to a central role for cellular immune responses in protecting from infection. [source]