Compositions and Methods Including Recombinant B Lymphocyte Cell Line Including an Exogenously Incorporated Nucleic Acid Expressing an Exogenous Membrane Immunoglobulin Reactive to a First Antigen and Including an Endogenous Gene Expressing an Endogenous Secreted Immunoglobulin Reactive to a Second Antigen

A method for producing at least one immunoglobulin in an isolated cell line comprising:

• introducing into at least one isolated B lymphocyte cell line at least one exogenous membrane immunoglobulin reactive to at least one first antigen to produce at least one first isolated B lymphocyte cell line;
• selecting the at least one first isolated B lymphocyte cell line expressing the membrane immunoglobulin reactive to the at least one first antigen;
• introducing into the at least one first isolated B lymphocyte cell line at least one exogenous nucleic acid encoding one or more secreted immunoglobulins reactive to at least one second antigen to produce at least one isolated recombinant B lymphocyte cell line;
• and
• selecting the at least one isolated recombinant B lymphocyte cell line expressing the one or more secreted immunoglobulin reactive to the at least one second antigen.

A method for producing at least one immunoglobulin in an isolated cell line comprising:

• introducing into at least one first isolated B lymphocyte cell line at least one exogenous nucleic acid encoding one or more secreted immunoglobulins reactive to at least one first antigen to produce at least one isolated recombinant B lymphocyte cell line;
• selecting the at least one isolated recombinant B lymphocyte cell line expressing the one or more secreted immunoglobulin reactive to the at least one first antigen;
• introducing into the at least one isolated B lymphocyte cell line at least one exogenous membrane immunoglobulin reactive to at least one second antigen to produce at least one first isolated B lymphocyte cell line;
• and
• selecting the at least one first isolated B lymphocyte cell line expressing the membrane immunoglobulin reactive to the at least one second antigen.