The invention relates to the field of therapeutic antibody development. The present invention relates to a mutant Fc domain based on the human IgG1 constant domain, whereby the mutations comprise a substitution of the asparagine at position 297 with an alanine, to prevent N-glycosylation, and additionally comprise two amino acid substitutions at position R292 and V302 with a cysteine as to increase the stability of those aglycosylated Fc-containing proteins by forming an additional disulfide bridge upon expression in a host. More specifically, the introduction of this specific combination of ...