<p>The present invention provides a recombinant domain antibody (dAb) which binds to human TNF-a, the dAb comprising an immunoglobulin heavy or light chain variable domain, wherein said variable domain comprises at least one complementarity determining region (CDR) having a sequence derived from a New World primate wherein the CDR is selected from the group consisting of YAATKLQS (SEQ ID No: l), YEASSLQS (SEQ ID No:2), YEASKLQS (SEQ ID No:3) and YSASNLET (SEQ ID No:4). The recombinant domain antibody is used to detect human TNF-a in a sample and to treat a disorder characterized by human TNF-a activity.</p>
