Abstract: The present invention relates to isolated nucleic acid molecules which encode an antigen from a Moraxella catarrhalis (Meat) species, a vector which comprises such nucleic acid molecule, and a host cell comprising such vector. Furthermore, the invention provides antigens from a Moraxella catarrhalis species, as well as fragments and variants thereof, a process for producing such antigens, and a process for producing a cell which expresses such antigen. More specifically, such antigens are produced by or associated with bacterial infections caused by Moraxella catarrhalis.