The 'connective tissue disease' array. A 48-feature collage derived from a 1536-feature 'connective tissue disease' array probed with serum from a patient with systemic lupus erythematosus (SLE) is presented. This array demonstrates specific detection of two representative autoantibody reactivities, against Ro52 (upper center box) and double-stranded DNA (dsDNA, lower right box). Antibodies against Candida skin test antigens (lower center box) are also detected, and serve as a positive control. This collage contains four features representing the reactive antigens (boxed) and control antigens (not boxed). Arrays were produced using a robotic microarrayer to attach putative connective tissue disease autoantigens (listed in text) to poly-L-lysine-coated microscopic slides. The depicted array was incubated with a 1:150 dilution of serum derived from a patient with SLE and with ELISA-confirmed reactivity against Ro and DNA. Antibody binding was detected by incubation with Cy-3-labeled antihuman IgG/IgM secondary antibody. Marker spots (spotted Cy-3-labeled IgG, left box) are used to orient the arrays. Detailed protocols for production, probing, and scanning antigen arrays are presented in our earlier work [17] and online [21].