Post-translational modification of human type II collagen (hCII) in the form of hydroxylation of Pro and Lys residues and glycosylation of some hydroxylated Lys residues has been shown to correlate with hCII arthritogenicity in susceptible strains of mice [1, 2]. At the epitope level, O-linked glycosylation of Lys264 located within the arthritogenic region hCII259–273 has been implicated in the creation of neoepitopes recognized by arthritogenic T cells . Macrophages and to lesser extent primed B cells have been implicated in processing hCII for presentation of hCII259–273 epitope to specific T cells [4, 5], whereas Langerhans dendritic cells are unable to process CII . Macrophages may thus play a pivotal role in activation of autoreactive T cells during collagen-induced arthritis. However, no information is available on the mechanisms of antigen processing of the glycosylated arthritogenic epitope, although it is likely to be crucial for an understanding of the activation of autoimmune T cells in rheumatoid arthritis.