Table 3.

Major differences between the two characteristic claims of Cabilly II and III, and potential relevance thereof

	Cabilly II	Cabilly III	Remarks
Required compound features
Type of molecule	Immunoglobulin molecule or functional fragment thereof	Antibody or fragment thereof having specificity for a desired antigen	Term “having specificity for a desired antigen” has probably been introduced to Cabilly III to anticipate a claim construction order with respect to the term immunoglobulin, as requested by a plaintiff in an earlier trial.
Variable domains?	Fv of HC	HC or fragment with Fv sequence	Cabilly III adds the term “sequence” to more explicitly include also subsequences of HC and LC.
	Fv of LC	LC or fragment with Fv sequence	Neither Cabilly II nor II protect antibodies which have only HC domains.
Constant domain?	Not required	Human Fc sequence of at least HC	Cabilly III does not protect antibodies devoid of a Fc, or antibodies which have a non-human HC Fc.
Required method features
Type of transformation	A single host cell transformed with DNA for Fv of HC and DNA for Fv of LC	Not specified	Scope of Cabilly II is restricted to methods in which one cell is transformed with two DNAs. Cabilly III has no such restriction.
Type of expression	Both DNAs are independently expressed in said host cell	Not specified (claim 38 says “coexpression”)	Neither “independent expression” nor “coexpression” are defined in the respective patents, although the former implies that both subunits can be expressed independently from one another (e.g., the DNAs are under control of different promotors), while the latter implies a synchronous and possible also quantitative expression of both subunits.
Type of antibody production	HCs and LCs are produced as separate molecules in said host cell	Culturing a recombinant host cell comprising DNA encoding for both chains or fragments and recovering the HC or fragment and LC or fragment