Expression of the membrane complement regulatory proteins (CD55 and CD59) in human thymus.

CD59 is one of the key molecules involved in cell protection against autologus complement. The fact that complement regulatory proteins are able to prevent hyperacute rejection of organs in pig to primate model, raises the question of possible complement regulatory protein (CRP) involvement in the maturation of immunological system. We report here that in foetal and postnatal human thymus, CD59 and CD55 are primarily located on Hassall's corpuscles and medullary epithelial cells. This localization highly correlates with the expression of CD30L, which is the member of the tumour necrosis factor superfamily. Additionally, TUNEL technique was used to visualize distribution of apoptotic cells in the thymus, which revealed the presence of apoptotic cells closely associated with the Hassall's corpuscles. The observed co-localization of CD59, CD55 and CD30L might suggest an involvement of the complement system in thymic selection in humans

Dengue Virus Type 2 Infections of Aedes aegypti Are Modulated by the Mosquito's RNA Interference Pathway

A number of studies have shown that both innate and adaptive immune defense mechanisms greatly influence the course of human dengue virus (DENV) infections, but little is known about the innate immune response of the mosquito vector Aedes aegypti to arbovirus infection. We present evidence here that a major component of the mosquito innate immune response, RNA interference (RNAi), is an important modulator of mosquito infections. The RNAi response is triggered by double-stranded RNA (dsRNA), which occurs in the cytoplasm as a result of positive-sense RNA virus infection, leading to production of small interfering RNAs (siRNAs). These siRNAs are instrumental in degradation of viral mRNA with sequence homology to the dsRNA trigger and thereby inhibition of virus replication. We show that although dengue virus type 2 (DENV2) infection of Ae. aegypti cultured cells and oral infection of adult mosquitoes generated dsRNA and production of DENV2-specific siRNAs, virus replication and release of infectious virus persisted, suggesting viral circumvention of RNAi. We also show that DENV2 does not completely evade RNAi, since impairing the pathway by silencing expression of dcr2, r2d2, or ago2, genes encoding important sensor and effector proteins in the RNAi pathway, increased virus replication in the vector and decreased the extrinsic incubation period required for virus transmission. Our findings indicate a major role for RNAi as a determinant of DENV transmission by Ae. aegypti

40. výročí založení seismické stanice Polom

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ECVAM's Activities in the EU Candidate Countries.

Abstract not availableJRC.I-Institute for Health and Consumer Protection (Ispra

ECVAM'S Activities in the EU Candidate Countries

ECVAM has been given a special grant for collaborative projects on alternative/advanced testing methods involving eleven Candidate Countries for membership of the European Union (Bulgaria, Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania, Slovakia and Slovenia). The project involves the promotion of the Three Rs (reduction, refinement, replacement) concept of Russell &amp; Burch, in cooperation with appropriate individuals and national and international organisations in the Candidate Countries themselves, and elsewhere. The scope of the programme's activities covers: conferences in some of the Candidate Countries, workshops, training courses, training visits, and technology development/transfer initiatives. A database of contacts in the Candidate Countries and in relevant institutions in other countries, is being compiled. </jats:p