Monoclonal Antibodies against Cell Wall Chitooligomers as Accessory Tools for the Control of Cryptococcosis.

Therapeutic strategies against systemic mycoses can involve antifungal resistance and significant toxicity. Thus, novel therapeutic approaches to fight fungal infections are urgent. Monoclonal antibodies (MAbs) are promising tools to fight systemic mycoses. In this study, MAbs of the IgM isotype were developed against chitin oligomers. Chitooligomers derive from chitin, an essential component of the fungal cell wall and a promising therapeutic target, as it is not synthesized by humans or animals. Surface plasmon resonance (SPR) assays and cell-binding tests showed that the MAbs recognizing chitooligomers have high affinity and specificity for the chitin derivatives. In vitro tests showed that the chitooligomer MAbs increased the fungicidal capacity of amphotericin B against Cryptococcus neoformans. The chitooligomer-binding MAbs interfered with two essential properties related to cryptococcal pathogenesis: biofilm formation and melanin production. In a murine model of C. neoformans infection, the combined administration of the chitooligomer-binding MAb and subinhibitory doses of amphotericin B promoted disease control. The data obtained in this study support the hypothesis that chitooligomer antibodies have great potential as accessory tools in the control of cryptococcosis.

Hepadnavirus detected in bile and liver samples from domestic pigs of commercial abattoirs.

BACKGROUND: Preliminary studies showed the prevalence of a virus similar to human hepatitis B virus (HBV-like) in swine from farms in China and the molecular evidence of Hepadnavirus infection in domestic pigs herds in Brazil. In this study, we genetically characterize the swine Hepadnavirus strains in swine from slaughterhouses located in certified abattoirs from Rio de Janeiro State, Brazil and evaluate its hepatotropic potential. RESULTS: Bile and liver samples from swine were positive for partial genome amplification (ORF S and ORF C), direct sequencing and viral load quantification. Sequencing of the gene encoding the surface antigen allowed classification of Hepadnavirus into genotypes, similar to HBV genotype classification. Indirect immunofluorescence confirmed the presence of HBsAg antigen in liver tissue sections. CONCLUSIONS: So far our data suggest that commercial swine house an HBV-like virus and this relevant finding should be considered in studies on the origin and viral evolution.

Production of Monoclonal Antibody That Recognizes Zika Virus and Other Flaviviruses in Serum-Free Conditions.

With the recent outbreaks of Zika and Dengue virus infections in various countries worldwide, production of vaccines or diagnostic kits is an urgent public health demand. Production of a monoclonal antibody (mAb) that specifically binds to a common antigen shared by the Flavivirus genus will be necessary for new diagnostic kits or characterization and viral identity tests during vaccine development. This study aimed to cultivate, in serum-free conditions, the 4G2 hybridoma that produces an mAb, which recognizes a shared epitope from the Flavivirus genus. We compared 4G2 hybridoma growth and biochemical profiles between cells cultivated in batch mode over 10 days in roller bottles containing Dulbecco's modified Eagle's medium high glucose containing 10% fetal bovine serum medium or hybridomas directly adapted to Ex-Cell serum-free medium. Cellular parameters such as specific growth rate (µ), maximum cell concentration, specific l-lactate, and glucose and IgG rates were evaluated. Thereafter, we also compared total mAb volumetric productivity, purification yield, and mAb staining of Vero cells infected with Zika and Dengue-2 virus. Direct adaptation to serum-free conditions did not change hybridoma growth rate and mAb production under the conditions tested. Instead, serum-free mAb purification showed a higher yield with no alterations on mAb structure or mAb staining of Zika and Dengue Vero-infected cells.

Theoretical investigation of the triphosphate forms of azidothymidine and thymidine.

In this paper we investigate (using AM1 semi-empirical as well as HF methods at the STO-3G, 3-21G, 6-31G, 6-31G* and 6-31+G** level) the conformations, geometrical parameters, Mulliken charges, and solvation effects of the triphosphate form of AZT (AZTTP), as well as the thymidine nucleotide (dTTP) structure. Our calculated geometrical parameters and Mulliken charges, with and without solvation effects, are correlated with recent experimental results.