Abstract: Methods of reversal of the binding between a biotin compound and a biotin-binding compound are disclosed. A method of reversibly releasing a biotinylated moiety from a streptavidin (or avidin) coated support is shown as an example. The strong interaction between streptavidin or avidin-biotin is made much weaker by using a combination of modified streptavidin or avidin and modified biotin like desthiobiotin or a derivative thereof like DSB-X Biotin. A protein, such as an antibody may be biotinylated with the modified biotin. When this protein is isolated by binding the modified biotin to the modified streptavidin or avidin bound to an solid surface, it may be released under very gently and very rapid conditions by addition of free biotin. In contrast to proteins obtained by the prior art release methods the protein obtained using the previously available release methods, the proteins obtained using the methods disclosed herein will maintain their native conformation.

Abstract: Methods of reversal of the binding between a biotin compound and a biotin-binding compound are disclosed. A method of reversibly releasing a biotinylated moiety from a streptavidin (or avidin) coated support is shown as an example. The strong interaction between streptavidin or avidin-biotin is made much weaker by using a combination of modified streptavidin or avidin and modified biotin like desthiobiotin or a derivative thereof like DSB-X Biotin. A protein, such as an antibody may be biotinylated with the modified biotin. When this protein is isolated by binding the modified biotin to the modified streptavidin or avidin bound to an solid surface, it may be released under very gently and very rapid conditions by addition of free biotin. In contrast to proteins obtained by the prior art release methods the protein obtained using the previously available release methods, the proteins obtained using the methods disclosed herein will maintain their native conformation.

Abstract: The present invention relates to an antibody expression library derived from a patient which has been immunochallenged with one or more foreign antigens associated with a particular disease or foreign agent, wherein said patients have been immunochallenged with the foreign antigens at a time point such that they still contain a repertoire of antibody producing cells which are enriched with cells producing antibodies directed to said foreign antigens associated with said disease or foreign agent, or at a time point such that they are still in an active phase of immune response to said foreign antigens associated with said disease or foreign agent. Methods of producing such expression libraries are also disclosed.