Comparative Study of Quinolines and Tetrahydroquinolines Sorption on Various Sorbents from Water-Acetonitrile Solutions

The retention of 16 quinoline and tetrahydroquinoline derivatives was investigated under liquid chromatography conditions using porous graphitized carbon (PGC), octadecyl silica (ODS) and hypercrosslinked polystyrene (HCLP) stationary phases. For most of the analytes, retention on PGC was greater than on ODS, while retention on HCLP was even greater than on both ODS and PGC. The non-linearity of retention dependencies on acetonitrile content in the eluent was observed for compounds containing carboxy, hydrazo and methoxy groups. The relationships between quinolines structure and their retention factors were investigated. It was found that sorption on different sorbents correlated with different descriptors. Retention on ODS was found to be highly correlated with lipophilicity only while on HCLP it depended on both lipophilicity and polarizability of the sorbates. The feature of PGC was a good correlation of retention factors with topological and geometrical parameters. Additionally, ability of PGC to form OH…π bonds with hydroxymethylquinolines was found. The observed regularities allow one to rationally optimize the chromatographic analysis of structurally similar compounds, which is very important for bioactive substances.

Combined virus-like particle-based polyepitope DNA/protein HIV-1 vaccine design, immunogenicity and toxicity studies

We have previously described designing of polyepitope immunogens TBI and TCI, to stimulate the humoral and cellular immune responses to HIV-1. Here, immunogens TBI and TCI were used to create new vaccine construct named CombiHIVvac (Combined HIV-1 vaccine). CombiHIVvac is a virus-like particles (VLP) containing the DNA vaccine pcDNA-TCI as a core encapsulated within a spermidine-polyglucin-TBI conjugate. The immunogenic and toxic properties of the candidate vaccine CombiHIVvac have been studied. CombiHIVvac induces a strong humoral and CTL responses in mice; the antibodies are highly specific and are able to neutralize HIV-1 in vitro. Preclinical study demonstrated that CombiHIVvac does not cause long-term changes in physiological, biochemical and morphological parameters in immunized animals and thus can be recommended for clinical trials.

[Different systems of delivery of HIV-1 DNA vaccine encoding the multiepitope CTL-immunogene]

We used, within the case study, virus-like particles (VLP) and attenuated strains of salmonella for the delivery of HIV-1 DNA vaccine encoding the multiepitope CTL-immunogene. The immunogenicity of the thus obtained vaccine constructions was comparatively analyzed. All constructions were shown to be able of inducing, in immunized animals, both the specific T-cell responses and the synthesis of virus-specific antibodies. The lowest level of immune response was registered in animals immunized by "naked" plasmid DNA. The delivery by plasmid DNA involving VLP or the attenuated strain of salmonella enhances the efficiency of the DNA-vaccine presentation to the immune system.

Comparative analysis using a mouse model of the immunogenicity of artificial VLP and attenuated Salmonella strain carrying a DNA-vaccine encoding HIV-1 polyepitope CTL-immunogen

Two systems have been examined for delivery of DNA-vaccine encoding a HIV-1 polyepitope CTL-immunogen (TCI). One is intended for i.m. injection and is in the form of an artificial virus like particle containing eukaryotic expression plasmid pcDNA-TCI encapsulated within a spermidine-polyglucin conjugate. The other is intended for mucosal immunization and is based on attenuated Salmonella typhimurium strain 7207, which can deliver pcDNA-TCI directly into professional antigen-presenting cells (APC). After immunization, the artificial VLP and recombinant Salmonella induced an enhanced HIV specific serum antibody, proliferative and CTL responses compared to those induced by naked pcDNA-TCI. The most significant responses were produced when pcDNA-TCI was delivered by Salmonella.

Designing and engineering of DNA-vaccine construction encoding multiple CTL-epitopes of major HIV-1 antigens

A synthetic T cell immunogen (TCI) has been designed as a candidate DNA-based vaccine against Human immunodeficiency virus (HIV)-1 using cytotoxic T lymphocytes (CD8(+) CTL) and T-helper lymphocytes (CD4(+) Th) epitopes retrieved from the Los Alamos HIV Molecular Immunology Database. The protein 392 amino acids in length contains about eighty CTL-epitopes, many of which are overlapping and are totally restricted by ten different HLA class I molecules. To be able to detect CTL responses induced by a DNA vaccine in experimental animals, additional epitopes, restricted by mouse and Macaque rhesus major histocompatibility complex (MHC) class I molecules, were included in the target immunogen. The gene encoding the TCI protein was assembled, cloned into vector plasmids and expressed in a prokaryotic and a eukaryotic system. The presence of HIV-1 protein fragments in the immunogen structure was ascertained by ELISA and immunoblotting using panels of HIV-1-positive sera and monoclonal antibodies to p24. It has been demonstrated that DNA vaccine can induce both specific T cell responses (CTL and blast transformation) and specific antibodies in mice immunized with pcDNA-TCI.

[Immune response in oral and rectal immunization by the attenuated strain of salmonella carrying the HIV DNA-vaccine]

The recombinant strain of Salmonella typhimurium SL7207/pBMC-env, carrying a plasmid containing the gene of protein HIV-1 gp-160, was obtained under the monitoring by CMV-promoter. The above strain was used in the rectal and oral immunization of BALB/c mice. HIV-specific antibodies were detected in serum after a one-time immunization; such antibodies were able to inhibit the viral replication in vitro. Furthermore, the shaping-up of the specific cytotoxic and of proliferative responses was registered. Finally, the rectal immunization by cells of the Salmonella recombinant strain can be regarded as a promising delivery system of DNA-vaccine (pBMC-env), and it is more effective versus the oral immunization variant.

[Construction and study of antigenic characteristics of recombinant salmonella strain producing TBI protein]

A recombinant strain producing TBI protein (artificial protein containing HIV-1 B and T cell epitopes) was constructed on the base of attenuated Salmonella typhimurium SL7207 strain and BALB/c mice were immunized with this strain in a dose of 10(9) live cells orally or rectally. A single immunization with the recombinant salmonella strain induced humoral and cellular immune response to HIV-1; hence, this strain is a promising candidate for vaccine against HIV.

[Incorporation of synthetic phospholipids into the membranes of the sarcoplasmic reticulum from the rabbit muscle]

The hydrophobic spin label used in ESR showed that the iminoxyl radical rotation in the native membrane of sarcoplasmatic reticulum (SR) occurred much faster than in the membranes, modified by a synthetic lipid. Such effect was observed throughout the whole temperature range (7-40 degrees). Experimental technique for the modification of the SR membrane and the lipid by ultrasonic treatment has been developed. Synthetic lipids without ultrasonic treatment did not inhibit the activity of Ca2+-ATPase. The change in both the enzyme activity and its ability to transport the Ca2+ ions through the membrane vesicules was observed after the phospholipids incorporation into the SR membrane. The investigation of the temperature dependence (in Arrhenius coordinates) of native and modified by lecithin Ca2+-ATPase after ultrasonic treatment and also of a "pure enzyme" showed the presence of two sharp breaks at 20 degrees and 40-42 degrees. It was shown tha the break of an Arrhenius anamorphosis was caused by a lipid environment of ATPase, "melting" of a phospholipid bilayer. The break at 20-22 degrees was observed in all cases and even after the incorporation of all the lipids into the SR membrane. This phenomenon can be explained by the distortion of the protein-lipid interaction, affecting the conformation mobility of protein and the geometry of its catalytically active center.