RESUMO
Objectives: A new vaccine candidate TB/FLU-05E has been developed at the Smorodintsev Research Institute of Influenza (Russia). The vaccine is based on the attenuated influenza strain A/PR8/NS124-TB10.4-2A-HspX that expresses mycobacterial antigens TB10.4 and HspX. This article describes the results of preclinical immunotoxicity and allergenicity studies of the new vector vaccine TB/FLU-05E against tuberculosis. Materials and Methods: The experiments were conducted on male CBA mice, С57/black/6 mice, and guinea pigs. The vaccine candidate was administered intranasally (7.7 lg TCID50/animal and 8.0 lg TCID50/animal) twice at a 21-day interval. The immunotoxic properties of the vaccine were assessed in mice according to the following parameters: spleen and thymus weight and their organ-to-body weight ratio, splenic and thymic cellularity, hemagglutination titer assay, delayed-type hypersensitivity test, and phagocytic activity of peritoneal macrophages. Histological examination of the thymus and spleen and white blood cell counts were also performed. Allergenicity of the vaccine was assessed in guinea pigs using conjunctival and general anaphylaxis reaction tests. Results: The results showed that double immunization with the TB/FLU-05E vaccine did not affect the phagocytic activity of peritoneal macrophages, cellular and humoral immunity after immunization with a heterologous antigen (sheep red blood cells), or the organ-to-body weight ratio of immunocompetent organs (thymus and spleen). The vaccine candidate demonstrated no allergenic properties. Conclusion: According to the results of this study, the TB/FLU-05E vaccine is well-tolerated by the immune system and demonstrates no immunotoxicity or allergenicity.
RESUMO
Neolignans honokiol and 4'-O-methylhonokiol (MH) and their derivatives have pronounced anti-inflammatory activity, as evidenced by numerous pharmacological studies. Literature data suggested that cyclooxygenase type 2 (COX-2) may be a target for these compounds in vitro and in vivo. Recent studies of [11C]MPbP (4'-[11C]methoxy-5-propyl-1,1'-biphenyl-2-ol) biodistribution in LPS (lipopolysaccharide)-treated rats have confirmed the high potential of MH derivatives for imaging neuroinflammation. Here, we report the synthesis of four structural analogs of honokiol, of which 4'-(2-fluoroethoxy)-2-hydroxy-5-propyl-1, 1'-biphenyl (F-IV) was selected for labeling with fluorine-18 (T1/2 = 109.8 min) due to its high anti-inflammatory activity confirmed by enzyme immunoassays (EIA) and neuromorphological studies. The high inhibitory potency of F-IV to COX-2 and its moderate lipophilicity and chemical stability are favorable factors for the preliminary evaluation of the radioligand [18F]F-IV in a rodent model of neuroinflammation. [18F]F-IV was prepared with good radiochemical yield and high molar activity and radiochemical purity by 18F-fluoroethylation of the precursor with Boc-protecting group (15) with [18F]2-fluoro-1-bromoethane ([18F]FEB). Ex vivo biodistribution studies revealed a small to moderate increase in radioligand uptake in the brain and peripheral organs of LPS-induced rats compared to control animals. Pretreatment with celecoxib resulted in significant blocking of radioactivity uptake in the brain (pons and medulla), heart, lungs, and kidneys, indicating that [18F]F-IV is likely to specifically bind to COX-2 in a rat model of neuroinflammation. However, in comparison with [11C]MPbP, the new radioligand showed decreased brain uptake in LPS rats and high retention in the blood pool, which apparently could be explained by its high plasma protein binding. We believe that the structure of [18F]F-IV can be optimized by replacing the substituents in the biphenyl core to eliminate these disadvantages and develop new radioligands for imaging activated microglia.
