Tumor immunotherapy by epicutaneous immunization requires langerhans cells.

A role for Langerhans cells (LC) in the induction of immune responses in the skin has yet to be conclusively demonstrated. We used skin immunization with OVA protein to induce immune responses against OVA-expressing melanoma cells. Mice injected with OVA-specific CD8(+) T cells and immunized with OVA onto barrier-disrupted skin had increased numbers of CD8(+) T cells in the blood that produced IFN-gamma and killed target cells. These mice generated accelerated cytotoxic responses after secondary immunization with OVA. Prophylactic or therapeutic immunization with OVA onto barrier-disrupted skin inhibited the growth of B16.OVA tumors. LC played a critical role in the immunization process because depletion of LC at the time of skin immunization dramatically reduced the tumor-protective effect. The topically applied Ag was presented by skin-derived LC in draining lymph nodes to CD8(+) T cells. Thus, targeting of tumor Ags to LC in vivo is an effective strategy for tumor immunotherapy.

The PRIME 1996 cruise: an overview

The UK PRIME cruise, June-July 1996 in the NE Atlantic, consisted of two legs. During the first, detailed chemical and biological observations were made in time-series mode adjacent to the centre of a cold-core eddy in the vicinity of 59 degreesN 20 degreesW using SF6 tracer techniques as the basis for the Lagrangian study. The eddy, which appeared to have been formed the previous winter, remained coherent over the 9 days of the survey and advected only slowly. The phytoplankton community in the eddy was dominated by the coccolithophorid Coccolithus huxleyi. High microzooplankton grazing rates indicated minimal export losses from the surface layer. Significant shifts in many, but not all, of the chemical and biological properties measured were observed over the course of the experiment, especially after the passage of a storm event, which resulted in considerable deepening of the mixed layer followed by a return to fully stratified conditions. The second leg consisted of a transect from 59 degreesN 20 degreesW to 37 degreesN 19 degreesW, with a further Lagrangian time-series study based on a drogue marker initiated at the southern end of the transect. Maximal biological activity was generally encountered in the region between two fronts located at 52.5 degreesN and 48 degreesN, while to the south of 48 degreesN oligotrophic conditions prevailed. At the southern Lagrangian site, a deep chlorophyll maximum was present and high column new production was recorded as a result of the euphotic zone extending below the depth of the nutricline. Microzooplankton grazing rates were lower at this location than at the northern eddy site. The influx of a warm, saline water body into the upper layers during the southern survey led to a major shift in many of the biological and chemical properties being measured. At both the northern and southern Lagrangian sites, the biomass of the mesozooplankton exceeded that of the microzooplankton. (C) 2001 Elsevier Science Ltd. All rights reserved.