Abnormal differentiation of thymocytes induced by free cyclosporine is avoided when cyclosporine bound to N-(2-hydroxypropyl)methacrylamide copolymer carrier is used.
BACKGROUND
The side effects of cyclosporine (CsA)-including nephrotoxicity and abnormal differentiation of thymocytes developing in the thymus-can be decreased or even avoided using targeted conjugates of CsA, where both targeting moiety and drug are bound to water-soluble polymeric carrier based on N-(2-hydroxypropyl) methacrylamide (HPMA).


METHODS
Irradiated, syngeneic bone marrow transplanted-mice (BALB/c and A/Ph) were treated intraperitoneally for 4 weeks with 20 mg/kg of free CsA, HPMA-conjugated CsA, or antibody-targeted HPMA-bound CsA. Immunohistology of the thymus was performed together with two-color flow cytometry to detect the effect of different forms of CsA on individual thymocyte subpopulations.


RESULTS
. We have shown that free CsA strongly abrogated T-cell development. The appearance of mature thymocytes expressing CD3(high) is almost completely inhibited (1.8%) after free CsA treatment, whereas these cells are well detectable in controls (22%) and HPMA polymer-bound CsA-treated animals (19%). Immunohistological studies have shown acellular rests of the medulla after free CsA treatment, whereas well-stained medullary thymocytes were detected in controls and after exposure to antibody-targeted HPMA. conjugated CsA.


CONCLUSIONS
HPMA-conjugates of CsA are generally more specific in their targeting to T lymphocytes. It was found that nonspecific binding of CsA to erythrocytes and plasma lipoproteins is significantly reduced using anti-CD3 targeted, HPMA polymer-bound CsA In addition, the entry of these macromolecules into the thymus is limited-probably due to the blood-thymus barrier-and HPMA conjugates of CsA, unlike free drug, do not abrogate T-cell development in bone marrow transplanted mice.
St'astný
M
M
Institute of Microbiology, Academy of Sciences of the Czech Republic, Department of Immunology and Gnotobiology, Prague.
Ulbrich
K
K
Strohalm
J
J
Rossmann
P
P
Ríhová
B
B
D000178:Acrylamides; D000818:Animals; D016026:Bone Marrow Transplantation; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D003208:Concanavalin A / Q000494:pharmacology; D016572:Cyclosporine / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D016503:Drug Delivery Systems; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000494:pharmacology*; D008074:Lipoproteins / Q000097:blood; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011108:Polymers; D051381:Rats; D013950:Thymus Gland / Q000166:cytology*
D000178:Acrylamides; D007166:Immunosuppressive Agents; D008074:Lipoproteins; D011108:Polymers; D003208:Concanavalin A; D016572:Cyclosporine; C032976:N-(2-hydroxypropyl)methacrylamide