Sporopollenin exine capsules (SECs) (outer exoskeletal wall of the spores of Lycopodium clavatum) were extracted and examined for their potential use as microcapsules. They were shown, by laser scanning confocal microscopy (LSCM), to be void of their inner contents. The removal of nitrogenous and other internal materials was supported by a combination of elemental and gravimetric analyses. Two different methods were investigated to encapsulate substances into SECs which were (i) mild passive migration of materials into the SECs and (ii) subjecting SECs and materials to a vacuum. A range of fluorescent dyes with different polarities were seen using LSCM to encapsulate efficiently into the SECs (up to 1 g.g À1 ). Relatively unstable materials with different polarities were encapsulated into the SECs: polyunsaturated oils, which are labile to oxidation, and the enzymes streptavidin-horseradish peroxidase (sHRP) and alkaline phosphatase (ALP). Irrespective of the encapsulation techniques employed no oxidation of the oils or denaturation of the enzymes was observed following their full recovery. This study gives the first indication of the viability of SECs to microencapsulate various potentially unstable materials without causing a detrimental effect.

A promising approach to increase the specificity of photosensitisers used in photodynamic therapy has been through conjugation to monoclonal antibodies (MAb) directed against tumour-associated antigens. Many of the conjugations performed to date have relied on the activated ester method, which can lead to impure conjugate preparations and antibody crosslinking. Here, we report the development of photosensitiser -MAb conjugates utilising two porphyrin isothiocyanates. The presence of a single reactive isothiocyanate allowed facile conjugation to MAb FSP 77 and 17.1A directed against internalising antigens, and MAb 35A7 that binds to a non-internalising antigen. The photosensitiser -MAb conjugates substituted with 1 -3 mol of photosensitiser were characterised in vitro. No appreciable loss of immunoreactivity was observed and binding specificity was comparable to that of the unconjugated MAb. Substitution with photosensitiser had a minimal effect on antibody biodistribution in vivo for the majority of the conjugates, although a decreased serum half-life was observed using a cationic photosensitiser at the higher loading ratios. Tumour-to-normal tissue ratios as high as 33.5 were observed using MAb 35A7 conjugates. The internalising conjugate showed a higher level of phototoxicity as compared with the non-internalising reagent, using a cell line engineered to express both target antigens. These data demonstrate the applicability of the isothiocyanate group for the development of high-quality conjugates, and the use of internalising MAb to significantly increase the photodynamic efficiency of conjugates during photoimmunotherapy.

We have identified a novel physiological anti-inflammatory pathway under the control of the transcription factor Erg; this pathway inhibits NF-κB-dependent transcription and TNF-α-induced inflammation in vivo. These results suggest a novel approach to anti-inflammatory therapies.