Growth
factor incorporation in biomedical constructs for their
local delivery enables specific pharmacological effects such as the
induction of cell growth and differentiation. This has enabled a promising
way to improve the tissue regeneration process. However, it remains
challenging to identify an appropriate approach that provides effective
growth factor loading into biomedical constructs with their following
release kinetics in a prolonged manner. In the present work, we performed
a systematic study, which explores the optimal strategy of growth
factor incorporation into sub-micrometric-sized CaCO3 core–shell
particles (CSPs) and hollow silica particles (SiPs). These carriers
were immobilized onto the surface of the polymer scaffolds based on
polyhydroxybutyrate (PHB) with and without reduced graphene oxide
(rGO) in its structure to examine the functionality of incorporated
growth factors. Bone morphogenetic protein-2 (BMP-2) and ErythroPOietin
(EPO) as growth factor models were included into CSPs and SiPs using
different entrapping strategies, namely, physical adsorption, coprecipitation
technique, and freezing-induced loading method. It was shown that
the loading efficiency, release characteristics, and bioactivity of
incorporated growth factors strongly depend on the chosen strategy
of their incorporation into delivery systems. Overall, we demonstrated
that the combination of scaffolds with drug delivery systems containing
growth factors has great potential in the field of tissue regeneration
compared with individual scaffolds.
A new platform for creating anti-coronavirus epitope vaccines has been developed. Two loop-like epitopes with lengths of 22 and 42 amino acid residues were selected from the receptor-binding motif of the Spike protein from the SARS‑CoV‑2 virus that participate in a large number of protein-protein interactions in the complexes with ACE2 and neutralizing antibodies. Two types of hybrid proteins, including one of the two selected epitopes, were constructed. To fix conformation of the selected epitopes, an approach using protein scaffolds was used. The homologue of Rop protein from the
Escherichia coli
ColE1 plasmid containing helix-turn-helix motif was used as an epitope scaffold for the convergence of C- and N-termini of the loop-like epitopes. Loop epitopes were inserted into the turn region. The conformation was additionally fixed by a disulfide bond formed between the cysteine residues present within the epitopes. For the purpose of multimerization, either aldolase from
Thermotoga
maritima
, which forms a trimer in solution, or alpha-helical trimerizer of the Spike protein from SARS‑CoV‑2, was attached to the epitopes incorporated into the Rop-like protein. To enable purification on the heparin-containing sorbents, a short fragment from the heparin-binding hemagglutinin of
Mycobacterium tuberculosis
was inserted at the C-terminus of the hybrid proteins. All the obtained proteins demonstrated high level of immunogenicity after triplicate parenteral administration to mice. Sera from the mice immunized with both aldolase-based hybrid proteins and the Spike protein SARS‑CoV‑2 trimerizer-based protein with a longer epitope interacted with both the inactivated SARS‑CoV‑2 virus and the Spike protein receptor-binding domain at high titers.
Supplementary information
The online version contains supplementary material available at 10.1134/S0006297921100096.
BackgroundE protein of tick-borne encephalitis virus (TBEV) and other flaviviruses is located on the surface of the viral particle. Domain III of this protein seems to be a promising component of subunit vaccines for prophylaxis of TBE and kits for diagnostics of TBEV.MethodsThree variants of recombinant TBEV E protein domain III of European, Siberian and Far Eastern subtypes fused with dextran-binding domain of Leuconostoc citreum KM20 were expressed in E. coli and purified. The native structure of domain III was confirmed by ELISA antibody kit and sera of patients with tick-borne encephalitis. Immunogenic and protective properties of the preparation comprising these recombinant proteins immobilized on a dextran carrier with CpG oligonucleotides as an adjuvant were investigated on the mice model.ResultsAll 3 variants of recombinant proteins immobilized on dextran demonstrate specific interaction with antibodies from the sera of TBE patients. Thus, constructed recombinant proteins seem to be promising for TBE diagnostics. The formulation comprising the 3 variants of recombinant antigens immobilized on dextran and CpG oligonucleotides, induces the production of neutralizing antibodies against TBEV of different subtypes and demonstrates partial protectivity against TBEV infection.ConclusionsStudied proteins interact with the sera of TBE patients, and, in combination with dextran and CPGs, demonstrate immunogenicity and limited protectivity on mice compared with reference “Tick-E-Vac” vaccine.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-1884-5) contains supplementary material, which is available to authorized users.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.