[Neuroinflammation: Dr Jekyll or Mr Hyde?].

Sheltered in a bony cage, populated by cells with little regenerative potential, the central nervous system (CNS) could likely not withstand classic inflammation without risking major sequelae. As a consequence, it had to develop an original way to provide surveillance, defence and reparation, which relies on both the complex architecture of the periphery-nervous parenchyma exchange zones, and the tightly regulated collaboration between all the cell populations that reside in or pass through the CNS. Despite its tight regulation, neuroinflammation is sometimes the cause of irreversible loss but it is also where the solution stands.

The intrasplenic circulation of three formulations of the same protein antigen.

This paper presents a kinetic study of the intrasplenic circulation of three formulations of the protein antigen conalbumin including the soluble form and two liposomal formulations, one encapsulated in the internal aqueous milieu and one surface-linked to the liposomal vehicle. These formulations differ not only in their physical status but also in their immunostimulating properties and were chosen in an attempt to correlate the movements of antigen in lymphoid tissues with the immune response elicited. The presence of conalbumin was followed over a period of 21 days using, as a detection system, an antibody that we developed and which allows for the visualization of antigenic peptides such as those presented at the surface of antigen-presenting cells (APC).

Effect of liposomal antigens on the priming and activation of the immune system by dendritic cells.

Dendritic cells (DCs) are recognized as the sole professional antigen-presenting cells capable of priming naive T cells of the helper and cytotoxic phenotypes. This property is presently exploited with success in vaccinal strategies against pathogens or tumor cells that otherwise escape immune recognition, but the repeated infusions of ex vivo expanded and sensitized DCs are usually required to achieve protection. In this paper, we demonstrate that liposomal antigens can efficiently relay and propagate the action of DCs, inducing a strong long-term response against their associated antigen.