Hi Ray, I don't know of any anti-rat CD34 monoclonal antibodies, but the rat equivalent of human CD133 was recently cloned. Indeed, the murine AC133 homologue was cloned before the human version, although I think the lawyers are still arguing about who did it first. The murine homologue was originally referred too as 'prominin' so if you search pubmed you will find a number of articles on this structure. Hopefully one of the groups working in this area will be in possession of an anti-rat reagent. I think the German group who first identified murine prominin may have a polyclonal reagent (at least). See Corbeil D, Fargeas CA, Huttner WB. Rat prominin, like its mouse and human orthologues, is a pentaspan membrane glycoprotein. Biochem Biophys Res Commun. 2001 Jul 27;285(4):939-44. One other thing, CD133 is not 'expressed exclusively on hematopoietic stem and progenitor cells'. It is present on epithelial cells too. A number of the early studies performed looking at the differential expression of AC133 on acute leukemias generated variable results, to say the least. Studies from reputable labs initially showed that ALLs were unreactive while some/most AMLs were reactive. Our studies of normal marrow CD34+ cells gated using standardised methods described in Current Protocols (unit 6.4) have invariably shown that AC133 does not bind to 'pre-B' cells (CD34+CD19+CD10+) cells within the total CD34+ fraction. The occasional identification of such cells in mobilised PB samples showed the same results. Thus we were in general agreement with the studies that showed that pre-B cell ALLs were unreactive. Since then, other reports have contradicted our own studies on normal marrow and also concluded that some (at least) ALLs also express CD133. While I am confident that the latter studies on normal marrow were not performed well enough at the technical level to contradict our findings, we have not performed a formal study of CD133 expression in acute leukemias. Cheers, Rob Sutherland University Health Network, Toronto ray hester wrote: > Hi, > > Can anyone help us find a source of antibodies specific for _rat_ CD34 and > AC133? If not, does anyone know of a source of antibody specific for these > antigens on cells from other species, but that also cross-react with rat > cells? > > AC133 is described as a cell surface antigen expressed exclusively on > hematopoietic stem and progenitor cells. Anti AC133 is available from > Miltenyi Biotec as an antibody reactive with human cells, but they haven't > tested it for reactivity with rat cells. Does anyone know if anti AC133 > reacts with a similarly distributed antigen on rat cells? > > Thanks for any help. > > Ray Hester > College of Medicine > Univ. of South Alabama > Mobile, AL 36688 > rhester@jaguar1.usouthal.edu
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