Chemistry Reference
In-Depth Information
presented in vivo. Hence they synthesised TF-containing glycopeptide
thiols based on a mucin peptide repeating unit, and then assembled into
gold nanoparticles. Sizing data showed that certain sugar presentations
resulted in the assembly of particles that may have reasonable uniformity
in their gold core diameters by TEM analysis, but they can be poly-
dispersed and 'non-uniform' in solution. Glycopeptide-coated nano-
particles result in more uniform particles as seen by TEM analysis,
however, GNP's and GPNP's contain some larger size elements that could
be a consequence of either aberrations in the self-assembly process or
aggregation events. An important conclusion gleaned from this work is
that nanoconstructions with various surface chemistries may display very
different properties when comparing microscopy to sizing measurements
in solution.
Surprisingly gold nanoparticles present a particular property: they
possess an intrinsic anti-angiogenic activity.
45
In fact they are capable to
bind heparin-binding growth factors like VEGF165 and bFGF, inhibiting
growth factor-mediated signalling. VEGF165 and bFGF are two endo-
thelial cell mitogens and mediators of angiogenesis.
It is known that highly patterned displays of antigens can lead to
earlier B cell amplification for potent IgM responses as well as ecient
switching to IgG. Antigen organization has a great influence on B cell
tolerance, with B cells unresponsive to poorly organized antigens while
responding promptly to the same antigen presented in a highly organized
manner. Recently, viral capsids have emerged as a promising platform
for antigen presentation. Peptide epitopes presented on the surface of
viral capsids can stimulate an adaptive immune response by effective
activation of antigen presenting cells as well as stimulation of B-cell
mediated response by direct cross-linking of B cell receptors.
46,47
Huang
and co-workers
48
selected the cowpea mosaic virus capsid (CPMV), which
is high immunogenic yet non-infectious to humans; in particular the
authors used a mutant capsid bearing reactive cysteines on the exterior
surface, for the selective conjugation with Tn antigens. The glycoconju-
gate was then injected into mice and pre- and post-immune antibody
levels in the mice sera were measured by enzyme-linked immunosorbant
assays. High total antibody titers and, more importantly, high IgG titers
specific for Tn were obtained in the post-immune day 35 serum, sug-
gesting the induction of T cell-dependent antibody isotype switching by
the glycoconjugate. The antibodies generated were able to recognize Tn
antigens presented in their native conformations on the surfaces of both
MCF-7 breast cancer cells and the multidrug resistant breast cancer cell
line NCIADR RES. These results suggest that the CPMV capsid can greatly
enhance the immunogenicity of weak antigens such as Tn and this can
provide a promising tool for the development of carbohydrate based
anti-cancer vaccines.
In addition magnetic glyco-nanoparticles (glyco-ferrites) rapresents
a usefull tool for selective immunolabeling and imaging of cells.
49,50
Chen
and co-workers synthesized a tri-antennary, galactoside-capped gallamide
dendron, that was eciently anchored onto the surface of CdSe/ZnS
core/shell nanoparticles in a covalent fashion (Fig. 6). The water-soluble
Search WWH ::
Custom Search