Study of apoptosis induced by cytostatics and vegetal extracts on human endothelial cell line.

Angiogenesis, the biological process by which new capillaries are formed from pre-existing vessels, is a tightly controlled and complex process involving several factors with both stimulating and inhibiting steps. In solid tumor growth, a specific clinical turning point is the transition to the vascular phase. Once it develops an intrinsic vascular network, a tumor grows indefinitely.

DNA vaccination of neonate piglets in the face of maternal immunity induces humoral memory and protection against a virulent pseudorabies virus challenge.

DNA vaccination represents a unique opportunity to overcome the limitations of conventional vaccine strategy in early life in the face of maternal-derived immunity. We used the model of pseudorabies virus (PRV) infection in pigs to further explore the potential of DNA vaccination in piglets born to sows repeatedly vaccinated with a PRV inactivated vaccine. A single immunisation of 8-week-old piglets with a DNA vaccine expressing secreted forms of PRV gB, gC, and gD, triggered an active serological response, confirming that DNA vaccination can over-ride significant residual maternal-derived immunity.

Vaccination of puppies with a lipid-formulated plasmid vaccine protects against a severe canine distemper virus challenge.

We assessed whether the formulation of a DNA vaccine expressing the canine distemper virus (CDV) hemagglutinin (HA) and fusion (F) immunogens with the cationic lipid DMRIE-DOPE could induce serological responses and protection against a severe CDV challenge in the dog. Although clear protection was observed in dogs vaccinated with formulated plasmids only limited CDV specific antibody titers were observed in protected dogs before challenge, suggesting that protection could be explained by cell-mediated immunity and/or by a strong antibody-based memory response (priming) triggered by the infectious challenge. The high level of protection achieved in this study, demonstrated that formulated DNA CDV vaccines can generate in dogs a level a protection comparable to conventional CDV vaccines.

Immunogenicity of IpaC-hybrid proteins expressed in the Shigella flexneri 2a vaccine candidate SC602.

We have investigated the capacity of live attenuated Shigella flexneri strains to act as vectors for the induction of local and systemic antibody responses against heterologous epitopes. The S. flexneri IpaC antigen was selected as a carrier protein into which the C3 neutralizing epitope of the poliovirus VP1 protein was inserted in eight sites distributed along IpaC.

Functional analysis of the Shigella flexneri IpaC invasin by insertional mutagenesis.

The ability of Shigella to enter epithelial cells, to escape from the phagocytic vacuole, and to induce apoptosis in macrophages requires the IpaB, IpaC, and IpaD proteins. An extracellular complex containing IpaB and IpaC can promote the uptake of inert particles by epithelial cells. To determine whether the function of IpaC is to act as an extracellular chaperone for IpaB in the Ipa complex or as an effector of entry involved in a direct interaction with the cell surface, we have constructed eight IpaC recombinant proteins by inserting the coding sequence for a 12- to 14-amino-acid fragment into restriction sites scattered within the ipaC gene.

Induction of a local anti-IpaC antibody response in mice by use of a Shigella flexneri 2a vaccine candidate: implications for use of IpaC as a protein carrier.

The capacity of Shigella flexneri to act as a delivery system for stimulation of local immunity was investigated by use of an S. Flexneri 2a vaccine candidate (SC602). This vaccine strain was constructed by deletion of virulence genes responsible for dissemination (icsA) and survival (iuc:iut) of bacteria within the colonic mucosa.

MxiG, a membrane protein required for secretion of Shigella spp. Ipa invasins: involvement in entry into epithelial cells and in intercellular dissemination.

Entry of Shigella flexneri into epithelial cells involves secretory proteins, the Ipa proteins, and their dedicated secretion apparatus, the Mxi-Spa translocon, which is encoded by the mxi and spa operons. We have characterized the mxiG gene that is located at the proximal part of the mxi operon. Inactivation of mxiG abolished lpa secretion, which indicates that MxiG is an essential component of the Mxi-Spa translocon.

Characterization of B-cell epitopes on IpaB, an invasion-associated antigen of Shigella flexneri: identification of an immunodominant domain recognized during natural infection.

The invasion plasmid antigen B (IpaB), a 62-kDa plasmid-encoded protein associated with the ability of shigellae to invade epithelial cells, is the bacterial antigen most strongly and consistently recognized by the host during infection. The strong systemic and mucosal immune responses observed against this invasin prompted us to map its B-cell epitopes. For this purpose, IpaB was first overexpressed in Shigella flexneri and used to raise rabbit polyclonal antiserum and murine monoclonal antibodies, which were subsequently used to screen a lambda gt11 ipaB library.

Some peculiarities of osteomedullary interrelations at the level of the lateral wall of the maxillary sinus.

Several structural aspects in the lateral wall of the maxillary sinus are shown, revealing the existence of some peculiarities of the osteomedullary relationships at this level, as for instance: a) a great density of vascular canals, b) a marked collagen density and a high degree of polymerization of the ground substance pleading for a great stability of the osseous structure, and c) a relative cellular scarcity inside the marrow-like spaces as an expression of a reduced reactive ability of bone marrow. It is considered that these peculiarities are not merely determined by specific functional needs of the bone as a tissue, but mainly by subordination of the latter to the requirements of the higher-ordered structural and functional levels served by a certain osseous zone.