Directed evolution of super-secreted variants from phage-displayed human Interleukin-2.

Selection from a phage display library derived from human Interleukin-2 (IL-2) yielded mutated variants with greatly enhanced display levels of the functional cytokine on filamentous phages. Introduction of a single amino acid replacement selected that way (K35E) increased the secretion levels of IL-2-containing fusion proteins from human transfected host cells up to 20-fold. Super-secreted (K35E) IL-2/Fc is biologically active in vitro and in vivo, has anti-tumor activity and exhibits a remarkable reduction in its aggregation propensity- the major manufacturability issue limiting IL-2 usefulness up to now. Improvement of secretion was also shown for a panel of IL-2-engineered variants with altered receptor binding properties, including a selective agonist and a super agonist that kept their unique properties. Our findings will improve developability of the growing family of IL-2-derived immunotherapeutic agents and could have a broader impact on the engineering of structurally related four-alpha-helix bundle cytokines.

Efecto de la dosis profiláctica de cloroquina sobre la expresión de receptores Fc de neutrófilos / Effect of prophylactic dosages of chloroquinine on the expression of neutrophil Fc receptors

Se describe el efecto in vivo de la cloroquinina administrada en dosis de 300 y 600 mg base semanales sobre la expresión de receptores Fc de neutrófilos en voluntarios sanos. A todos los individuos se les realizó el estudio al inicio de los 6 meses de administración de la droga. Se encontraron diferencias estadisticamente significativas (p<0,01) entre los valores obtenidos antes del tratamiento y a las 6 semanas del mismo, en el grupo que recibe la dosis de 600 mg por semana

[Interaction of immune complexes and their leukocyte receptors: regulation by the complement system and by cyclophosphamide]. / Interacción de los complejos inmunes y sus receptores leucocitarios: su regulación por el sistema complemento y la ciclofosfamida.

During the course of this investigation we have studied different aspects related to the interaction between immune complexes (CI) and their cellular receptors for the Fc-fragment of IgG (RFc gamma). Our first approach was to demonstrate that the alternative pathway of complement is the main one responsible for the CI-dissociation from their receptors of human peripheral mononuclear cells. This modulatory effect was studied throughout the functional restoration of antibody dependent cellular cytotoxicity (CCCDA), which is a mechanism susceptible to Cl-inhibition. The results suggest that the levels of circulating Cl do not necessarily correlate with the tissue damage they produce. Secondly, we have demonstrated that cyclophosphamide (Cy), which is a potent immunomodulating drug which has been used for the treatment of diseases characterized by high levels of Cl, enhances the capacity of the mononuclear phagocytic system to remove IgG-particulate complexes in mice. Finally, we have described a nonspecific cytotoxic system triggered by Cl against different target cells, through a mechanism that involves the reactive metabolites of O2.

Quimioterapia antineoplástica y comportamiento en la recuperación celular, receptores Fc y C3 de médula ósea / Antineoplastic chemotherapy, recovery of bone marrow cells and Fc and C3 cellular receptors

La acción de los fármacos antibeoplásicos in vitro cultivo de médula ósea murina ha mostrado ser un buen modelo experimental para valorar los efectos citotóxicos en la proliferación mioloide y el daño a receptores Fc y F3 de granulocito-monocito. En este trabajo se expusieron los cultivos celulares a la acción de dósis medias terapéuticas en el plasma de Amethopterina, Ara-C, Vincristina y Doxorrubicina, mostrando daño a la proliferación celular y a receptores FC y C3, estadisticamente significativo, comparado con el testigo positivo. Se intentó además verla recuperación celular después de haber eliminado el quimioterápeutico del cultivo y volver a poner los estimulos para tal fin. Como resultado encontramos que la recuperación celular fue tan rápida en los cultivos donde cesó el efecto de la quimioterápia, como en el testigo positivo que no habia recibido medicamento pero sí los factores estimulantes (MCP), lo cual, comparado con el testigo nehativo que no habia recibido éstod, la diferencia fue significativa (p<0.05). Algo paredcido sucedió con los receptores a Fc Y C3 de granulocitos-monocitos .