Targeting antiretroviral nucleoside analogues in phosphorylated form to macrophages: in vitro and in vivo studies.

Abstract

A number of nucleoside analogues are active against the infectivity of human immunodeficiency virus (HIV); however, their use is limited by toxic side effects and by limited phosphorylation in the infected cells. In an attempt to overcome these problems, a drug delivery system has been developed. A prototype of these drugs in a form already phosphorylated (2',3'-dideoxycytidine 5'-triphosphate; ddCTP) was encapsulated into erythrocytes. Subsequently, by the addition of Zn, an arrangement of band 3 in clusters was induced (band 3 is the major transmembrane protein in erythrocytes). The immune system recognizes these clusters as nonself, promoting autologous IgG binding and phagocytosis by cells of the monocyte-macrophage lineage. In this way, ddCTP encapsulated into erythrocytes was delivered to macrophage cells, where concentrations >2 FAM were found. Addition of ddCTP-loaded erythrocytes to macrophages previously infected by HIV-1 results in almost complete inhibition of HIV production over 3 weeks in culture. Administration of ddCTP-loaded erythrocytes to LP-BM5-infected mice at 10-day intervals over a period of 3 months results in reduction of lymphoadenopathy, splenomegaly, and hypergammaglobulinemia. Thus, the delivery of nucleoside analogues in phosphorylated form is feasible, and selective targeting to virus reservoirs (macrophage cells) can be accomplished by the use of autologous erythrocytes.

Erythrocyte-mediated delivery of drugs, peptides and modified oligonucleotides

“…We have proved that this is true both in vitro and in vivo and that new compounds can also be designed, synthesized and delivered using erythrocytes as carriers. 14,[15][16][17][18] Among peptides interesting results were obtained in our laboratory by the delivery of a ubiquitin analogue 19 ( Figure 3). This peptide is stable in the erythrocytes and efficiently competes with endogenous ubiquitin in macrophages.…”

Administration of Fludarabine-Loaded Autologous Red Blood Cells in Simian Immunodeficiency Virus-Infected Sooty Mangabeys Depletes pSTAT-1-Expressing Macrophages and Delays the Rebound of Viremia after Suspension of Antiretroviral Therapy

“…In particular, compared to the loading procedure followed for human RBC, the osmolarity of dialysis buffer was increased and the dialysis time was prolonged. Targeting of fludarabine-loaded RBC to macrophages was achieved by inducing band 3 clustering as described previously (29). To study fludarabine metabolite formation in SM RBC, fludarabine-loaded RBC were incubated at 0.5% hematocrit (Ht) in RPMI 1640 medium containing fetal calf serum.…”

“…To selectively deliver fludarabine to M/M we used red blood cells (RBC) as carriers by taking advantage of the peculiar phagocytic capacity of M/M. Our group has validated the use of RBC as specific carriers for M/M with various compounds and in several different in vitro and in vivo models (13,15,28,29). The fludarabine-loaded RBC technology allows us to overcome the nonspecific toxic effect of fludarabine on actively replicating cells (such as lymphocytes), which are more sensitive than resting cells (such as M/M) to the DNA polymerase inhibition induced by the drug (20,21).…”

Efficient inhibition of macrophage TNF‐α production upon targeted delivery of K48R ubiquitin

“…K48R-ubiquitin was encapsulated into erythrocytes by a procedure consisting of hypotonic dialysis, isotonic resealing and reannealing essentially as reported in Magnani et al (1992).…”