Immunization scheme for variant surface glycoprotein carriers

Abstract

The invention pertains to an immunization scheme for inducing or amplifying an immune response involving Variant Surface Glycoproteins as carriers for antigenic structures against which the immune response is targeted. The invention is based on a specific priming and boosting schedule using the array presented and soluble VSG variants. Surprisingly, the immunization scheme of the invention elicits a strong and long-lasting antibody response in the immunized subject and therefore is applicable in vaccination approaches, immunotherapy and in the production of novel antibodies.

1 . A method for eliciting an immune response, and/or for amplifying a pre-existing immune response, against an antigenic compound in a subject, comprising at least one priming-immunization step and at least one boosting-immunization step, wherein the at least one boosting-immunization step is performed after the at least one priming-immunization step, and wherein:
 (i) The at least one priming-immunization step comprises an immunization of the mammal with an array of immunization-carrier-fusions on a vesicle or bead, and wherein each immunization-carrier-fusion is composed of a carrier protein fused to the antigenic compound; and   (ii) The at least one boosting-immunization step comprises an immunization of the mammal with the immunization-carrier-fusion used in (i) in a non-aggregated, preferably soluble form.   
     
     
         2 . The method of  claim 1 , wherein the immunization-carrier-fusion is an antigenic particle coated with an engineered variant surface glycoprotein (eVSG), wherein the eVSG comprises the antigenic compound covalently linked, optionally via a linker, to the N-terminus of the VSG carrier protein. 
     
     
         3 . The method of  claim 1 , wherein the immunization-carrier-fusion has the following (covalent) structure from N- to C-terminus: antigenic compound, a sortagging donor sequence, a sortagging acceptor sequence, a linker, a VSG protein sequence. 
     
     
         4 . The method of  claim 1 , wherein the antigenic compound is a disease associated antigen, for example a cancer antigen, an allergen or a viral immunogen, or is a dependency causing substance selected from (i) delta tetrahydrocannabinol (THC) or Synthetic cannabinoids, such as classical cannabinoids, non-classical cannabinoids, hybrid cannabinoids, aminoalkylindoles, and eicosanoids; for example Δ9-THC HU-210, (C8) CP 47,497, JWH-018, AM-2201 (Fluorinated JWH-018), UR-144, XLR-11 (Fluorinated UR-144), APICA, STS-135 (Fluorinated APICA). AB-PINACA, PB-22, 5F-PB-22 (Fluorinated PB-22); or (ii) methamphetamine and derivatives thereof such as 3,4-methylenedioxy-methamphetamine (MDMA)Ecstasy/Molly; or (iii) a synthetic cathinone like alpha-pyrrolidinopentiophenone (alpha-PVP); or (iv) an opioid including heroin, synthetic opioids such as fentanyl or related compounds such as carfentanyl, and other opioid pain relievers, such as oxycodone (OxyContin®), hydrocodone (Vicodin®), codeine, morphine, desomorphine (Krokodil); or (v) steroids (anabolic substances), or is nicotine. 
     
     
         5 . The method of  claim 1 , to wherein the carrier protein is a VSG protein derived from  Trypanosoma brucei.    
     
     
         6 . The method of  claim 1 , wherein the vesicle or bead is coated with more than one immunization-particle fusions, preferably more than 10 immunization-particle fusions per particle. 
     
     
         7 . The method of  claim 1 , wherein the immunization-carrier used in the method is a VSG protein, and wherein the VSG protein used as carrier in (i) and (ii) are derived from the same VSG protein type, for example the VSG in both (i) and (ii) are VSG3 of  Trypanosoma brucei.    
     
     
         8 . The method of  claim 1 , wherein the method comprises at least two priming-immunization steps, and wherein all of the priming immunization steps are performed prior to any of the boosting-immunization steps. 
     
     
         9 . The method of  claim 1 , wherein the method comprises at least two boosting-immunization steps, and wherein all of the boosting immunization steps are performed after any of the priming-immunization steps. 
     
     
         10 . The method of  claim 1 , wherein the subject is selected from an animal having an adaptive immune system, such as vertebrates such as birds (chicken), and mammals such as mouse, rabbit, camel, goat, rat, dog, cat, monkey, hamster or other mammals, or is a human, such as a human patient in need of an elicited or amplified immune response. 
     
     
         11 . A non-therapeutic method for generating antibodies against an antigenic-compound, the method comprising performing in a non-human animal the method of  claim 1 , and isolating from the non-human animal antibodies or B-cells producing antibodies against the antigenic compound. 
     
     
         12 . An antibody, or an antibody producing B-cell, generated and/or isolated according to a method of  claim 11 . 
     
     
         13 . An immunization kit, the immunization kit comprising (a) an aggregate of immunization-carrier protein on a vesicle or bead as recited in  claim 1 , and (b) a non-aggregated, preferably soluble form, of the immunization-carrier protein of (a); wherein the immunization-carrier protein of (a) and (b) are capable to be fused to an antigenic compound to obtain an immunization-carrier-fusion recited in  claim 1 . 
     
     
         14 . A pharmaceutical composition, comprising the immunization-carrier-fusion  claim 1 .