This invention provides novel nitrocellulose-based or Hydrogel-based microarrays and methods of making and using them (1) to detect the presence of one or more agents in a sample, (2) to determine the amount of one or more agents in a sample, (3) to determine whether a subject is afflicted with a disorder, and (4) to determine whether an agent known to specifically bind to a first compound also specifically binds to a second compound. This invention also provides kits which comprise the instant microarrays. This invention further provides antibodies capable of specifically binding to a glycomer present both on the surface of a mammalian macrophage or intestinal epithelial cell, and on a bacterial cell. Finally, this invention provides diagnostic methods using the instant antibodies.