Clinical hematological and biochemical parameters in Swiss,BALB/c,C57BL/6 and B6D2F1 Mus musculus

Background:Animal models are widely used in scientific research in order to obtain information from a whole organism under a specific set of experimental conditions.Various lineages of mice have been used to investigate diseases and new therapeutic strategies,and,consequently,hematological and biochemical tests in these laboratory animals are essential to validate scientific studies.Our study seeks to establish reference values for hematological and biochemical parameters of four lineages of mice.Methods:We evaluated the hematological and biochemical profiles of 20 males and 20 females from the lineages Swiss(heterogeneous),BALB/c and C57BL/6(isogenic),and B6D2F1(hybrid),totaling 160 mice.Analysis were standardized using the systems pocH-100iV Diff™for 19 hematological parameters and VITROS®350 for 12 biochemical parameters.Results:Results are shown as means and standard deviation,grouped by lineage and genre.Comparing the values obtained in this study with the values from previous studies,some variations were detected,which could be explained by differences in methodologies or individual variability.Conclusion:Thus our study shows that knowledge and disclosure of the values of physiological parameters of laboratory animals is necessary,and emphasises the importance of considering variations influenced by gender,lineage and genotype in the choice of the best experimental model.

Mycobacterium bovis BCG as a Delivery System for the dtb Gene Antigen from Diphtheria Toxin

Diphtheria is a fulminant bacterial disease caused by toxigenic strains of Corynebacterium diphtheriae whose local and systemic manifestations are due to the action of the diphtheria toxin (DT). The vaccine which is used to prevent diphtheria worldwide is a toxoid obtained by detoxifying DT. Although associated with high efficacy in the prevention of disease, the current anti-diphtheria vaccine, one of the components of DTP (diphtheria, tetanus and pertussis triple vaccine), may present post vaccination effects such as toxicity and reactogenicity resulting from the presence of contaminants in the vaccine that originated during the process of production and/or detoxification. Therefore, strategies to develop a less toxic and at the same time economically viable vaccine alternatives are needed to improve existing vaccines in use worldwide. In this study, the Moreau substrain of BCG which is used in Brazil as a live vaccine against human tuberculosis was genetically modified to carry and express the gene encoding for the diphtheria toxin fragment B (DTB). As such, the DNA sequence encoding the dtb gene was cloned into the pUS977 shuttle vector for cytoplasmic expression and successfully introduced into BCG cells by electroporation. Mice immunized with recombinant BCG expressing DTB showed seroconversion with the detection of specific antibodies against DTB. Also, rBCGs stably expressing DTB persisted up to 60 days in the absence of selective pressure in mice and cell viability did not change significantly during the period tested. Finally, immune sera from BALB/c mice vaccinated with rBCGpUS977dtbPW8 were preliminarily tested for their capacity of neutralizing the diphtheria toxin in the Vero Cells assay.