Cedarlane's Immunocolumns are simple, rapid, non-magnetic affinity chromatography tools for the enrichment and isolation of T- and B-cell sub-populations. By a process of negative selection, virtually all undesired cells are removed from the sample. Eluted cells are fully functional, and may be used in further applications. Of particular interest are the Human CD3/CD45 and CD4/CD45 columns. Most human naive T cells express CD45RA. This isoform of CD45 contains a segment encoded by an exon designated A. In contrast, most activated and memory T-cells express an isoform of CD45 in which the exon RNA has been spliced out - CD45RO. The Cedarlane CD3/CD45 and CD4/CD45 immunocolumns utilise this difference for selective enrichment. All regular columns can be loaded with approximately 1.24x10^8 cells; the high capacity columns can load 4.0-6.0x10^8 cells