TABLE 1.

H. influenzae isolates used in this study

Strain	Relevant characteristics	Reference
KW20-MI	Isolate of KW20 in MedImmune strain collection	5, 21
KW20-H3	Isolate of KW20 in Weiser strain collection	5, 21
H446	lic1 knockout of KW20-H3, ChoP not expressed	12
H491	lic1 constitutive “on” mutant of KW20-H3, ChoP expressed constitutively	12
H418	HAS+ 4C4− variant of nontypeable clinical isolate H233	18
H419	HAS− 4C4− variant of nontypeable clinical isolate H233	18
H420	HAS− 4C4+ variant of nontypeable clinical isolate H233	18