Monoclonal antibodies (MAbs) against human recombinant interferon beta (hrIFNbeta) were generated by genetic immunization (GI). In order to test two viral promoters frequently used in mammalian expression plasmid vectors, mice were inoculated four times by intramuscular injection, without adjuvant, with 100 microg of either pcDNA 3.1hrIFNbeta or pZeoSV2IFNbeta containing the entire human interferon beta gene and under the control of, respectively, human cytomegalovirus (HCMV) immediate-early promoter or early SV-40 enhancer/promoter. Only serum samples from mice immunized with pZeoSV2IFNbeta were positive to anti-hrIFNbeta. The spleens of the immunized mice were fused with myeloma Sp2/0 cells and the hybridoma clones generated screened by an in house enzyme-linked immunosorbent assay (ELISA). Fourteen MAbs were selected as reactive with hrIFNbeta. Western blot analysis was performed and only one recognized the 18 kDa isoform (non-glycosylated) of hrIFNbeta. All MAbs were subjected to antibody isotype characterization with a commercial ELISA and showed unusual profile with simultaneous expression of both IgM and IgG2a isotypes. This observation is further supported by RT-PCR amplification of the IgM CH4 domain using total RNA from hybridomas.

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a worldwide health problem. In a previous study, a murine monoclonal antibody (mMAB), capable of binding to PBP2a within MRSA strains, was generated. F(ab') antibody fragments are widely described in the literature as immunochemical tools and reagents for diagnostics and therapeutics, particularly because of their low immunogenicity and rapid pharmacokinetics. In this study, F(ab') fragments from mMAB were generated by enzymatic digestion, using pepsin. They were purified by affinity chromatography using protein A and concentrated by a MWCO 50 kDa filtration unit. The results indicate that it is possible to obtain F(ab') fragments by pepsin digestion. ELISA, western blotting, and fluorescence microscopy data demonstrated that F(ab') affinity for PBP2a is not lost even after the enzymatic digestion process. As expected, in the pharmacokinetics tests, F(ab') presented a faster elimination (between 12 and 18 h) compared to IgG. These F(ab') fragments could be used in future immunodiagnostic applications, including in vitro or in situ radiolabeling and in the treatment of infections caused by this important pathogen.

O desenvolvimento de novas drogas e vacinas contra doenças humanas passa, na maioria das vezes, por ensaios prévios em modelos animais. Staphylococcus aureus é um patógeno causador de infecções graves, muitas vezes resistentes aos antimicrobianos. Grande parte da população é portadora nasal desta bactéria. O desenvolvimento de estratégias para descolonização nasal necessita de modelos animais para a realização de estudos preliminares. O presente trabalho tem por finalidade demonstrar a adaptação do protocolo de González-Zorn as condições locais do modelo de colonização nasal por S. aureus em camundongos balb/C. Neste estudo, os animais foram inoculados pela via nasal com 108 bactérias, sendo submetidos a eutanásia no terceiro e sexto dia. Observou-se uma recuperação media de 104 (19.100) e 102 (180) bactérias, nos dias 3 e 6 respectivamente. O modelo avaliado mostrou-se ideal para utilização em estudos preliminares, visando avaliar a colonização nasal por S.aureus em modelo murino.

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