Preventive Activity against Influenza (H1N1) Virus by Intranasally Delivered RNA-Hydrolyzing Antibody in Respiratory Epithelial Cells of Mice.

The antiviral effect of a catalytic RNA-hydrolyzing antibody, 3D8 scFv, for intranasal administration against avian influenza virus (H1N1) was described. The recombinant 3D8 scFv protein prevented BALB/c mice against H1N1 influenza virus infection by degradation of the viral RNA genome through its intrinsic RNA-hydrolyzing activity. Intranasal administration of 3D8 scFv (50 µg/day) for five days prior to infection demonstrated an antiviral activity (70% survival) against H1N1 infection. The antiviral ability of 3D8 scFv to penetrate into epithelial cells from bronchial cavity via the respiratory mucosal layer was confirmed by immunohistochemistry, qRT-PCR, and histopathological examination. The antiviral activity of 3D8 scFv against H1N1 virus infection was not due to host immune cytokines or chemokines, but rather to direct antiviral RNA-hydrolyzing activity of 3D8 scFv against the viral RNA genome. Taken together, our results suggest that the RNase activity of 3D8 scFv, coupled with its ability to penetrate epithelial cells through the respiratory mucosal layer, directly prevents H1N1 virus infection in a mouse model system.

Metaloproteinasas y piel / Metalloproteinases and the skin

Las metaloproteinasas son endopeptidasas que desarrollan una función degradativa, generalmente dirigida a la matriz extracelular. Están relacionadas estructuralmente y se clasifican según su especificidad de sustrato y su estructura primaria. Su denominación se efectúa siguiendo una numeración correlativa según su fecha de descripción, pero existen para ellas nombres alternativos que hacen referencia generalmente al sustrato al que se dirigen o a su ubicación. El análisis de la estructura primaria de estas enzimas permite identificar los llamados dominios estructurales. Todos los miembros de las metaloproteinasas contienen un péptido señal, un propéptido y un dominio catalítico aminoterminal que contiene el sitio fijador de cinc. En la piel existen una serie de circunstancias tanto fisiológicas como patológicas en las que se evidencia un aumento de producción de metaloproteinasas. Ocurre en la reparación de heridas, en el envejecimiento cutáneo, en las enfermedades am (AU)

Enzyme/abzyme prodrug activation systems: potential use in clinical oncology.

Clinically useful prodrug activation systems for cancer therapy can be applied in combination with the exogenous activating enzymes, by which masked prodrugs are able to unmask to exert cytotoxic effects on the target tumors. In essence, designing prodrugs not to be degenerated or activated by the endogenous enzymes is needed. Prodrug activation systems are to be delivered to the tumor site by delivery tools, including antibodies, genes, viral vectors and synthetic polymers, directed to the target tumors. Highly selective accumulation of the prodrug activation system at the tumor site is critically important for the efficacy of the prodrug activations. Genetic engineering of antibodies have made it possible to create a bispecific antibody and its derivatives, which are of special value to the functional antibodies with one arm to direct the target tumor tissues, and another to recruit the effector cells or molecules that can effectively kill the tumor cells. The technology has further opened the window for catalytic antibodies as a prodrug activating system. Catalytic antibodies have two distinct advantages over the enzymes: First, they can be selected to catalyze the reaction that is not catalyzed by the endogenous enzymes. Second, in order to minimize immunogenicity, humanization is applicable to catalytic antibodies. In viewing the concept and experimental data with a few clinical trials of recent approaches of prodrug activation systems, their potential utility in clinical oncology is further discussed.

Using antibody catalysis to study the outcome of multiple evolutionary trials of a chemical task.

Catalytic aldolase antibodies generated by immunization with two different, but structurally related, beta-diketone haptens were cloned and sequenced to study similarities and differences between independently evolved catalysts. Kinetic and sequence analysis coupled with mutagenesis, structural, and modeling studies reveal that the defining event in the evolution of these catalysts was a somatic mutation that placed a lysine residue in a deep, yet otherwise unrefined, hydrophobic pocket. We suggest that covalent chemistries may be as readily selected from the immune repertoire as the traditional noncovalent interactions that have formed the basis of immunochemistry until this time. Further, we believe that these experiments recapitulate the defining events in the evolution of nature's enzymes, particularly as they relate to chemical mechanism, catalytic promiscuity, and gene duplication.