Immunization methods for rapidly enhancing human antibody titers; methods for preparing human antibodies against target antigens using non-human animals.

Abstract

This invention provides a rapid antibody preparation technology using non-human animals with human antibody genes as a platform technology capable of serving as a global pandemic response preparation. More specifically, this invention provides an immunization method capable of inducing high antigen-binding capacity of antibodies or high antibody titers of antisera in a short period of time, and a method for rapidly preparing broadly neutralizing human antibodies / antisera. (1) An immunization method that rapidly induces human monoclonal antibodies or human polyclonal antibodies with high binding capacity against a target antigen, the method comprising the step of immunizing a non-human animal multiple times within 30 days from the initial immunization with the target antigen or nucleic acid encoding the antigen, the non-human animal containing human antibody genes or loci, and in the non-human animal, the endogenous gene or locus corresponding to the human antibody gene or locus is destroyed or deleted, or has a variant of loss of expression or low expression. (2) A method for preparing human antibodies, which uses a non-human animal to prepare human antibodies against a target antigen, and includes the following steps: an immunization step, which immunizes the non-human animal with the antigen or a nucleic acid encoding the antigen; a human immunoglobulin-positive B cell isolation step, which isolates human immunoglobulin-positive B cells from the tissue of the immunized non-human animal; an antibody base sequence acquisition step, which obtains the base sequences of cDNA from antibody heavy chain mRNA and cDNA from antibody light chain mRNA prepared from the isolated B cells; and an antibody preparation step, which prepares an antibody based on the obtained antibody base sequence; wherein the non-human animal contains a human antibody gene or locus, and in the non-human animal, the rodent endogenous gene or locus corresponding to the human antibody gene or locus is destroyed or deleted, or has a variant of absent or low expression.

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