Endowing self-binding feature restores the activities of a loss-of-function chimerized anti-GM2 antibody

Our previous studies have described a rare type of antibody that spontaneously binds to itself, or homodimerizes. This self-binding, or autophilic antibody provides stronger protection against bacterial infection than a non-self-binding antibody with identical specificity and affinity, due to an increase of polymeric avidity. Furthermore, we have shown that a peptide derived from the self-binding domain of the autophilic T15 antibody can be crosslinked to the Fc carbohydrate of monoclonal antibodies specific for the B-cell receptor of B-cell tumors. These peptide-crosslinked antibodies can exert self-binding properties, leading to an increase in binding efficiency to the target cells as well as an increase in potential to induce apoptosis. Herein, we report a novel finding that crosslinking of the autophilic T15 peptide rescues a loss-of-function chimerized (ch) anti-GM2 antibody. The parental antibody demonstrates in vivo anti-tumor activity against melanoma xenografts. The T15 peptide-conjugated antibody shows the ability to bind to itself, as well as an increased binding to its antigen, ganglioside GM2. Moreover, the peptide-conjugated antibody also demonstrates an increased ability to bind to two GM2-positive tumor cell lines and notably important, restores its ability to induce apoptosis in two types of tumor cells. These results provide strong support for the clinical potential of the autophilic technology.     

Characterization of a plant-produced recombinant human secretory IgA with broad neutralizing activity against HIV

Recombinant Secretory IgA (SIgA) complexes have the potential to improve antibody-based passive immunotherapeutic approaches to combat many mucosal pathogens. In this report, we describe the expression, purification and characterization of a human SIgA format of the broadly neutralizing anti-HIV monoclonal antibody (mAb) 2G12, using both transgenic tobacco plants and transient expression in Nicotiana benthamiana as expression hosts (P2G12 SIgA). The resulting heterodecameric complexes accumulated in intracellular compartments in leaf tissue, including the vacuole. SIgA complexes could not be detected in the apoplast. Maximum yields of antibody were 15.2 μg/g leaf fresh mass (LFM) in transgenic tobacco and 25 μg/g LFM after transient expression, and assembly of SIgA complexes was superior in transgenic tobacco. Protein L purified antibody specifically bound HIV gp140 and neutralised tier 2 and tier 3 HIV isolates. Glycoanalysis revealed predominantly high mannose structures present on most N-glycosylation sites, with limited evidence for complex glycosylation or processing to paucimannosidic forms. O-glycan structures were not identified. Functionally, P2G12 SIgA, but not IgG, effectively aggregated HIV virions. Binding of P2G12 SIgA was observed to CD209 / DC-SIGN, but not to CD89 / FcalphaR on a monocyte cell line. Furthermore, P2G12 SIgA demonstrated enhanced stability in mucosal secretions in comparison to P2G12 IgG mAb.     

Cryptococcus shivajii sp. nov.: A Novel Basidiomycetous Yeast Isolated from Biogas Reactor

Five yeast morphotypes were isolated from biogas reactors at North Wyke Research, Okehampton, UK. Out of the five morphotypes, four were identified as known species. In contrast, the fifth morphotype strain, Bio10^T, was found to differ from Bullera dendrophila and Kwoniella mangroviensis, its closest phylogenetic neighbours, by 2.6–2.9% with respect to the nucleotide sequence of the D1/D2 domain of the 26S rRNA gene and by 5.6–6.2% with respect to the internal transcribed spacer 1 (ITS1)-5.8S rRNA gene-ITS2 region. Bio10^T also differs from these two species by a number of phenotypic characteristics. Thus, based on the phenotypic differences and phylogenetic analysis, strain Bio10^T is assigned the status of a new species of Cryptococcus, for which the name Cryptococcus shivajii sp. nov. is proposed. The type strain is Bio10^T (NCYC 3541^T = CBS 11374^T).     

How long can glacier foreland species live?

Age determinations provide information on longevity of the species and on their population structure. This knowledge is of particular interest for species involved in succession. On a glacier foreland of the Central Alps age determinations of six target species (Saxifraga oppositifolia, Oxyria digyna, Artemisia mutellina, Anthyllis vulneraria ssp. alpestris, Trifolium pratense ssp. nivale and Helianthemum grandiflorum) were carried out by means of herbchronology. The species were selected on three differently aged moraines in order to compare pioneer, early and late successional species. Pioneer species were expected to have young, invasive populations. This was suggested also for populations of late successional species growing towards the glacier front where they substitute the pioneer species. These hypotheses were only confirmed for the pioneer Saxifraga oppositifolia. The longest life span was found for Helianthemum grandiflorum on the oldest moraine. Plant size of all investigated individuals correlated with age. Significant differences where observed between the age of vegetative and generative individuals.     

Regeneration of neural crest derivatives in the <Emphasis Type="Italic">Xenopus</Emphasis>tadpole tail

Background  

After amputation of the Xenopus tadpole tail, a functionally competent new tail is regenerated. It contains spinal cord, notochord and muscle, each of which has previously been shown to derive from the corresponding tissue in the stump. The regeneration of the neural crest derivatives has not previously been examined and is described in this paper.