Induction of antigen specific immunologic tolerance

Abstract

Antigen specific immune tolerance is induced in a mammalian host by administration of a toleragen in combination with a regimen of immunosuppression. The methods optionally include a preceding conditioning period, where immunosuppressive agents are administered in the absence of the toleragen. After the tolerizing regimen, the host is withdrawn from the suppressive agents, but is able to maintain specific immune tolerance to the immunogenic epitopes present on the toleragen. Optimally, the toleragen will have high uptake properties that allow uptake in vivo at low concentrations in a wide variety of tolerizing cell types.

What is claimed is:  
     
         1 . A method of inducing antigen specific immune tolerance in a mammal having an anamnestic response to said antigen, comprising administering an effective dose of a toleragen comprising a high uptake moiety during a tolerization regimen wherein said host is maintained on a T cell immunosuppressive agent; 
 wherein following said tolerization regimen, upon withdrawal of said T cell immunosuppressive agent, the immunoglobulin titer against said antigen in said mammalian host is reduced as compared to the immunoglobulin titer against said antigen prior to said tolerization regimen, and wherein said mammal otherwise comprises a substantially normal immune system.    
     
     
         2 . The method according to  claim 1 , wherein tolerization regimen further comprises administration of an antiproliferative agent.  
     
     
         3 . The method according to  claim 2 , wherein said tolerization regimen is preceded by a conditioning period, said conditioning period comprising: 
 administering a combination of said T cell immunosuppressive agent and said antiproliferative agent in the absence of said toleragen for a period of time sufficient to suppress host T cell responses.    
     
     
         4 . The method according to  claim 2 , wherein an initial dose of said T cell immunosuppressive agent is administered to maintain suppressive levels of said agent in the host blood at trough level.  
     
     
         5 . The method according to  claim 2 , wherein during said tolerization regimen, said host is maintained on a combination of a T cell immunosuppressive agent and an antiproliferative agent for a period of at least 6 weeks.  
     
     
         6 . The method according to  claim 2 , wherein said T cell immunosuppressive agent is an immunophilin.  
     
     
         7 . The method according to  claim 6 , wherein said immunophilin is cyclosporin A.  
     
     
         8 . The method according to  claim 7 , wherein an initial dose of said cyclosporin A is administered such that the trough level is at least about 200 ng/m.  
     
     
         9 . The method according to  claim 7 , wherein an initial dose of said cyclosporin A is administered such that the trough level is at least about 300 ng/mls.  
     
     
         10 . The method according to  claim 2 , wherein said antiproliferative agent is a nucleotide analog.  
     
     
         11 . The method according to  claim 10 , wherein said nucleotide analog is a 6-mercaptopurine drug.  
     
     
         12 . The method according to  claim 10 , wherein said 6-mercaptopurine drug is azathioprine.  
     
     
         13 . The method according to  claim 2  wherein said antiproliferative agent is an antimetabolite drug.  
     
     
         14 . The method according to  claim 13 , wherein said antimetabolite drug is an inhibitor of dihydrofolate reductase or other enzymes involved in nucleotide metabolism.  
     
     
         15 . The method according to  claim 13 , wherein said nucleotide metabolic enzyme is dihydrofolate reductase and said inhibitor is methotrexate, or an analogs thereof.  
     
     
         16 . The method according to  claim 12 , wherein said azathioprine is maintained at a dose from 1 to 5 mg/ml/day for at least about two weeks.  
     
     
         17 . The method according to  claim 2 , comprising: 
 administering an effective dose of said toleragen at least 6 times during a tolerization regimen of at least about 6 weeks.    
     
     
         18 . The method according to  claim 17 , wherein said effective dose of said toleragen is less than 50% of the normal therapeutic dose.  
     
     
         19 . The method according to  claim 17 , wherein said effective dose of said toleragen is less than 10% of the normal therapeutic dose.  
     
     
         20 . The method according to  claim 17 , wherein said toleragen is a polypeptide for which a high uptake receptor is widely expressed in said mammalian host.  
     
     
         21 . The method according to  claim 17 , wherein said toleragen comprises mannose 6 phosphate.  
     
     
         22 . The method according to  claim 21 , wherein said toleragen is a mannose 6 phosphate conjugate of an antigen of interest.  
     
     
         23 . The method according to  claim 17 , wherein said toleragen is a therapeutic polypeptide.  
     
     
         24 . The method according to  claim 23 , wherein said therapeutic polypeptide is selected from the group consisting of antibodies, clotting factors, enzymes and growth factors.  
     
     
         25 . The method according to  claim 17 , wherein said toleragen is an autoantigen.  
     
     
         26 . The method according to  claim 25 , wherein said toleragen comprises a plurality of autoantigens.  
     
     
         27 . The method according to  claim 16 , wherein said toleragen comprises a transplantation antigen.  
     
     
         28 . The method according to  claim 27 , wherein said toleragen comprises a plurality of transplantation antigens.  
     
     
         29 . The method according to  claim 23 , wherein said toleragen is iduronidase.  
     
     
         30 . The method according to  claim 29 , wherein said iduronidase comprises a mannose 6 phosphate moiety.  
     
     
         31 . The method according to  claim 24 , wherein said clotting factor is Factor VIII.  
     
     
         32 . The method according to  claim 31 , wherein said Factor VIII is wherein said Factor VIII is conjugated to a high uptake moiety.  
     
     
         33 . The method according to  claim 32 , wherein said high uptake moiety is iduronidase comprising a high affinity uptake marker on its N-linked carbohydrates.  
     
     
         34 . The method according to  claim 1 , wherein said toleragen comprises a β-cell antigen.  
     
     
         35 . The method according to  claim 34 , wherein said β-cell antigen is selected from the group consisting of glutamic acid decarboxylase (GAD), IA2 and insulin.  
     
     
         36 . The method according to  claim 35 , wherein said β-cell antigen is GAD.  
     
     
         37 . The method according to  claim 36 , wherein said GAD is conjugated to a high uptake moiety.  
     
     
         38 . The method according to  claim 36 , wherein said high uptake moiety is a peptide that binds to a receptor selected from the group consisting of transferrin receptor, melanotransferrin receptor and mannose 6-phosphate receptor.  
     
     
         39 . The method according to  claim 36 , wherein said high uptake moiety is a peptide that binds to a mannose 6-phosphate receptor.  
     
     
         40 . The method according to  claim 39 , wherein said peptide is insulin-like growth factor-2 (IGF2).