Abstract: Provided are heterodimer pairs comprising a first heterodimer and a second heterodimer wherein each heterodimer comprises an immunoglobulin heavy chain or fragment thereof and an immunoglobulin light chain. At least one of the heterodimers comprises amino acid modifications in the CH1 and/or CL domains, amino acid modifications in the VH and/or VL domains or a combination thereof. The modified amino acid residues are part of the interface between the light chain and heavy chain and are modified in order to create preferential pairing between each heavy chain and a desired light chain such that when the two heavy chains and two light chains of the heterodimer pair are co-expressed in a mammalian cell, the heavy chain of the first heterodimer preferentially pairs with one of the light chains rather than the other. Likewise, the heavy chain of the second heterodimer preferentially pairs with the second light chain rather than first.

Abstract: Provided herein are stabilized chimeric Fabs derived from a parent chimeric Fab having a lambda light chain. The stabilized chimeric Fabs comprise an immunoglobulin heavy chain polypeptide construct from the parent chimeric Fab, having a CH1 sequence and a VH sequence, as well as a Vlambda-Ckappa chimeric light chain construct. The Vlambda sequence of the chimeric light chain construct corresponds to that of the parent chimeric Fab, and comprises one or more stabilizing amino acid modifications that increase the thermal stability of the stabilized chimeric Fab compared to the parent chimeric Fab. The stabilized Fabs are useful as therapeutic polypeptides, or can be used to prepare antibody constructs in other formats. The stabilized chimeric Fabs may also be useful generally to increase the stability of antibodies having lambda light chains.

Abstract: Compounds having cytotoxic and/or anti-mitotic activity are disclosed. Methods associated with preparation and use of such compounds, as well as pharmaceutical compositions comprising such compounds, are also disclosed. Also disclosed are compositions having the structure: (T)-(L)-(D), wherein (T) is a targeting moiety, (L) is an optional linker, and (D) is a compound having cytotoxic and/or anti-mitotic activity.