No abstract

The native Invaplex (Invaplex) vaccine and adjuvant is an ion exchange-purified product derived from the water extract of virulent species. The key component of Invaplex is a high-molecular-mass complex (HMMC) consisting of the lipopolysaccharide (LPS) and the invasin proteins IpaB and IpaC. To improve product purity and immunogenicity, artificial Invaplex (Invaplex) was developed using recombinant IpaB and IpaC proteins and purified LPS to assemble an HMMC consisting of all three components. Characterization of Invaplex by various methods demonstrated similar characteristics as the previously reported HMMC in Invaplex. The well-defined Invaplex vaccine consistently contained greater quantities of IpaB, IpaC, and LPS than Invaplex. Invaplex and Invaplex immunogenicities were compared in mouse and guinea pig dose escalation studies. In both models, immunization induced antibody responses specific for Invaplex and LPS while Invaplex induced markedly higher anti-IpaB and -IpaC serum IgG and IgA endpoint titers. In the murine model, homologous protection was achieved with 10-fold less Invaplex than Invaplex and mice receiving Invaplex lost significantly less weight than mice receiving the same amount of Invaplex. Moreover, mice immunized with Invaplex were protected from challenge with both homologous and heterologous serotypes. Guinea pigs receiving approximately 5-fold less Invaplex compared to cohorts immunized with Invaplex were protected from ocular challenge. Furthermore, adjuvanticity previously attributed to Invaplex was retained with Invaplex. The second-generation Invaplex vaccine, Invaplex, offers significant advantages over Invaplex in reproducibility, flexible yet defined composition, immunogenicity, and protective efficacy. species are bacteria that cause severe diarrheal disease worldwide, primarily in young children. Treatment of shigellosis includes oral fluids and antibiotics, but the high burden of disease, increasing prevalence of antibiotic resistance, and long-term health consequences clearly warrant the development of an effective vaccine. One vaccine under development is termed the invasin complex or Invaplex and is designed to drive an immune response to specific antigens of the bacteria in an effort to protect an individual from infection. The work presented here describes the production and evaluation of a new generation of Invaplex. The improved vaccine stimulates the production of antibodies in immunized mice and guinea pigs and protects these animals from infection. The next step in the product's development will be to test the safety and immune response induced in humans immunized with Invaplex.

A water soluble vitamin B(12)-rhenium conjugate was synthesized and used in concert with intrinsic factor to screen for cubilin receptor-mediated uptake in lung cancer cells. Internalization of the conjugate demonstrated that it could be used to rapidly screen for the cubilin receptor in living cells, subsequently confirmed with Western blotting and RT-PCR.

Nucleoside-derived drugs play an important role in the treatment of cancer. Here, we present the synthesis and characterization of an intriguing series of N3 conjugated Re(CO)(3) thymidine complexes. The complexes were characterized by NMR spectroscopy and mass spectrometry and their cytotoxicity was assessed against A549 cells. A similar dependence on the spacer length and the toxicity has been found for N3 functionalized complexes as recently reported for their C5' counterparts. A remarkable cytotoxic complex 22, carrying a dodecylene spacer at position N3 with a bis-quinoline metal chelate moiety, with an IC(50) value of 3.4 ± 1.6 μM, has been identified. Addition of a 100-fold excess of thymidine did not statistically reduce the observed cytotoxicity of all complexes. Cellular uptake studies of complex 22 have been performed by fluorescent microscopy, showing that compound 22 was clearly internalized into A549 cells. Temperature dependent uptake studies, blocking experiments with thymidine, and endosomal co-localization suggest that uptake of 22 occurs via passive diffusion and endocytosis.

Nucleoside analogues are extensively used in the treatment of cancer and viral diseases. The antiproliferative properties of organorhenium(I) complexes, however, have been scarcely explored to date. Herein we present the syntheses, characterization, and in vitro evaluation of Re(I)(CO)(3) core complexes of thymidine and uridine. For the binding of the Re(I)(CO)(3) core, a tridentate dipicolylamine metal chelate was introduced at positions C5', C2', N3, and C5 with spacers of various lengths. The corresponding organometallic thymidine complexes were fully characterized by IR and NMR spectroscopy and mass spectrometry. Their cytotoxicity was assessed against the A549 lung carcinoma cell line. Toxicity is dependent on the site and mode of conjugation as well as on the nature and the length of the tether. Moderate toxicity was observed for conjugates carrying the rhenium moiety at position C5' or N3 (IC(50)=124-160 microM). No toxicity was observed for complexes modified at C2' or C5. Complex 53, with a dodecylene spacer at C5', exhibits remarkable toxicity and is more potent than cisplatin, with an IC(50) value of 6.0 microM. To the best of our knowledge, this is the first report of the antiproliferative properties of [M(CO)(3)](+1)-nucleoside conjugates. In competitive inhibition experiments with A549 cell lysates and purified recombinant human thymidine kinase 1 (hTK-1), enzyme inhibition was observed for complexes modified at either N3 or C5', but our results suggest that the toxicity cannot be attributed solely to interaction with hTK-1.