![]() In 1983, Bollone and colleagues reported that bloodstained fibers were positive for both A and B molecules, assigning a blood type of AB. What is most likely being visualized in such samples are aged red blood cell membranes that have resealed during the preparation procedure, representing reconstituted cells, not intact red blood cells that have survived over large periods of time. Remarkably, red blood cells have been detected microscopically in ancient samples, including mummies, prehistoric rock tools, and also the Shroud. When aged blood is involved, these techniques are slightly modified since red blood cells become dehydrated and eventually rupture. For fresh blood, typing tests are fast, inexpensive, and relatively foolproof. This is the type of test typically performed at local blood drives. In forward typing of fresh blood, samples are mixed with freshly added antibodies and evaluated for their ability to clump, or agglutinate. This statement inadvertently refers to reverse typing, which is somewhat less informative and more difficult to interpret on its own (see below).įorward typing methods: What the data show When the statement “all old blood is degraded to AB” is evaluated in the context of ABO structure, it doesn’t make much sense, as degradation would result in aged blood being converted to type O. The O molecule doesn’t receive a terminal sugar, but exists as the (unmodified) core structure. That is, a person with a particular blood type (A, B, AB, or O) doesn’t contain antibodies in his or her serum against the A or B molecules they themselves express, but will contain antibodies specific for the A or B molecules they lack.ĪBO molecules are a branched chain of carbohydrates (sugars) that share the same core structure, but are uniquely modified by a different terminal sugar to create A and B molecules. The presence of ABO molecules on red blood cells and antibodies directed against these molecules in the serum are complementary within an individual. Both forward and reverse typing methods have been utilized in the study of the Shroud. Second, there is reverse typing, which measures the presence of antibodies in the serum (essentially the fluid component of blood), specifically the presence of antibodies to ABO blood group molecules. First, there is forward typing, which measures the presence of specific molecules on the surfaces of red blood cells (RBC): the ABO molecules. The idea that “aged blood is degraded to (or reverts to) type AB” is rather misleading.īlood typing is typically performed using two distinct methods that measure two very different things. ![]() I appreciate the opportunity to address the issue that “All old blood types as AB”, particularly in reference to the study of the Shroud. ![]() Kearse, a card-carrying immunologist writes:
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |