Search

The recombinant bacillus of Calmette and Guerin (BCG) vaccine effectively provides protection against Leishmania major in immunized BALB/c mice. The recombinant vaccine was developed by cloning and expressing the gp63 gene of Leishmania major in BCG under the influence of two microbial expression systems. The capability of recombinant BCG to decrease lesion development does not depend on the mode of vaccination. The experimental set up of the development of the recombinant BCG vaccine is discussed.

To accurately quantify the different outcomes of Leishmania major infection and to evaluate the fraction of zoonotic cutaneous leishmaniasis (ZCL) cases prevented by naturally acquired leishmanin skin test (LST) reactivity, a cohort of 470 children was followed up in 2 endemic foci, Remada and Dhiba, in southern Tunisia. During May 1997, before the ZCL emergence season, LST was performed, and results were reassessed 12 months later. Active case detection during the ZCL emergence season showed a high incidence of ZCL: 57.0% in Remada and 13.7% in Dhiba. The preventive fraction of ZCL conferred by LST reactivity increased proportionally with the reaction size before the emergence season, revealing a dose-response effect of approximately 70%. In addition, asymptomatic L. major infection appeared to be a significant form of natural immunization, particularly in the context of relatively low transmission. These findings may help in the design and evaluation of vaccines. Copyright © 2005 Infectious Diseases Society of America [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate a possible pathogenic role of cytokines in Behçet's disease (BD) by focusing on the analysis of cytokine gene expression within mucocutaneous BD lesions. METHODS: The study group comprised 20 patients with active BD. In this group, a set of chemokines as well as Th1 and Th2 cytokines in biopsy specimens obtained from oral and genital ulcers, pseudofolliculitis lesions, and lesions at the site of pathergy testing were studied using real-time quantitative reverse transcriptase-polymerase chain reaction. RESULTS: We observed important increases in the expression of interleukin-8 (IL-8) ( approximately 700-fold), monocyte chemoattractant protein 1 ( approximately 65-fold), interferon-gamma ( approximately 71-fold), and IL-12 ( approximately 69-fold) messenger RNA in BD lesions compared with normal skin. Except for IL-10 ( approximately 75-fold increase), Th2 cytokines (i.e., IL-4 and IL-13) were absent. CONCLUSION: Our data suggest a direct role of Th1 lymphocytes in the pathogenesis of mucocutaneous BD lesions. [ABSTRACT FROM AUTHOR]

Natural autoantibodies (NaAb) and IgG antibodies to tetanus toxoid (TT) were analysed in the sera of 38 children with active visceral leishmaniasis (VL) previously vaccinated with TT and in 30 healthy controls matched for sex and age. Patients exhibited high levels of NaAb to a panel of self antigens (tubulin, myosin, myoglobin, actin) contrasting to a low level of IgG to TT. Analysis of the circulating B cells in 26 untreated patients showed a low percentage of CD5+ per total B cells (3-66%, mean 36.6%) compared with 14 normal controls (17.8-66.6%, mean 52.7%) (P < 0.001). Evaluation of these parameters after antimonial therapy showed a significant decrease of the level of the NaAb (P < 0.0005), and a spontaneous increase of the level of the IgG to TT without any vaccine boosting (P < 0.01). In contrast, there was a significant increase in CD5+ B cells (P < 0.0005). This result suggests that CD5+ B cells may be sequestrated in parasitized lymphoid organs and may be released after remission. These findings show that the polyclonal B cell activation that occurs during active VL involves mainly B cells bearing NaAb and are in favour of a functional dichotomy of B cells. [ABSTRACT FROM AUTHOR]

The specificity of circulating and kidney-bound IgA during IgA nephoropathy is still a matter of discussion. In the present study, high levels of IgA antibodies directed against a panel of self and non-self antigens were found in the serum from patients with IgA nephropathy and were eluted from four out of the seven kidney biopsies studied. After immunoadsorption of pooled selected serum samples on TNP and actin-coated columns, polyspecific IgA antibodies were eluted. This supports the hypothesis that IgA-bearing B cells clones most probably producing polyspecific antibodies are a major feature of human IgA nephropathy. These findings also suggest that it may be hazardous to draw conclusions from the finding of apparently monospecific IgA antibodies in this condition. [ABSTRACT FROM AUTHOR]

Abstract: Leishmania histone H2B has been reported to be a promising candidate for both vaccination and serodiagnosis. We evaluated the cellular immune responses induced by H2B and its divergent amino-terminal (H2B-N) and conserved carboxy-terminal (H2B-C) regions in individuals with a history of Localized Cutaneous Leishmaniasis (LCL) due to Leishmania (L.) major. H2B induced significantly high PBMC proliferation and IFNγ levels in LCL individuals whereas significantly lower proliferation and IFNγ levels were observed with the divergent part of the protein. All proteins induced IL10 in LCL and healthy individuals. We also evaluated the humoral responses induced by these proteins in patients with Mediterranean Visceral Leishmaniasis (MVL) due to L. infantum. H2B and H2B-N were highly recognized by MVL sera. Our results show that the entire H2B protein is more efficient than its amino- and carboxy-terminal regions in inducing a dominant Th1 profile in cured LCL subjects and suggest that this protein may constitute a potential vaccine against leishmaniasis. Furthermore, H2B and H2B-N are interesting antigens for serodiagnosis of MVL. [Copyright &y& Elsevier]