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

ABSTRACT

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.