Methods and compounds for raising antibodies and for screening antibody repertoires

A method of isolating single antibody-producing particles having specificity for a selected antigen, comprising:

• 1) preparing vesicles, preferably exosomes, displaying a selected antigen and a marker;
• 2) contacting said vesicles of step 1 with an antibody repertoire;
• and,
• 3) identifying and isolating single antibody-producing particles reacting with said vesicles.

A method of isolating particles producing a single antibody specific of a variant antigen from an antibody repertoire comprising:

• 1) preparing a first population of vesicles, preferably exosomes, displaying said variant antigen and a marker;
• 2) preparing a second population of vesicles, preferably exosomes, displaying the native antigen and not displaying said marker;
• 3) suspending said antibody repertoire with the first and second populations of vesicles the second population being in excess;
• and,
• 4) identifying and isolating single antibody-producing particles reacting with the vesicles of step 1.

A method of expressing a polypeptide having at least one transmembrane domain at the surface of exosomes, comprising:

• 1) Providing a genetic construct encoding said polypeptide or a portion thereof comprising at least one transmembrane domain;
• 2) Introducing said construct and overexpressing said polypeptide or a portion thereof comprising at least one transmembrane domain into exosome-producing cells to generate recombinant exosomes;
• and
• 3) Collecting said recombinant exosomes, wherein said exosomes carry at their surface polypeptides encoded by said genetic construct.

A method of producing an antibody that binds a polypeptide having at least one transmembrane domain or an epitope thereof, comprising:

• 1) Providing a genetic construct encoding said polypeptide or a portion thereof comprising at least one transmembrane domain;
• 2) Introducing said construct and overexpressing said polypeptide or a portion thereof comprising at least one transmembrane domain into exosome-producing cells to generate recombinant exosomes presenting said polypeptide or epitope at their surface;
• 3) Collecting said recombinant exosomes and injecting said exosomes or a portion thereof to a non-human mammal to generate antibodies that bind said polypeptide or epitope;
• and,
• 4) Collecting antibodies or antibody-producing cells from said mammal.

A method of cloning of a sequence in a vector without introducing mutations at the cloning sites comprising the steps of:

• 1) providing a vector containing a cloning cassette framed by two restriction sites recognized by Type IIs restriction enzymes such that the restriction sites are removed from said vector after restriction enzyme cleavage;
• 2) providing said sequence with compatible extremities;
• 3) incubating said vector with said restriction enzyme;
• 4) ligating said sequence and said vector resulting from step 3.
• 5) isolating said vector comprising said sequence.