Introduction. A broken arm or wrist is usually caused by a fall onto an outstretched arm. It typically takes about six to eight weeks to heal in adults, and less time in children. Doctors refer to all breaks or cracks in bones as fractures.Go to your nearest accident and emergency (A&E) department if you think you or your child has broken a bone.t typically takes about six to eight weeks to heal in adults, and less time in children. Doctors refer to all breaks or cracks in bones as fractures. Go to your nearest accident and emergency (A&E) department if you think you or your child has broken a bone.
In contrast, the overwhelming majority of antigens for T cells are proteins, and these must be fragmented and recognized in association with MHC products expressed on the surface of nucleated cells, not in soluble form.
Memory B-cells bear membrane-bound isotypes other than IgM, representing whatever Ig the cell will begin secreting upon antigenic stimulation. TcR. The T-cell antigen receptor (TcR) is the principle defining marker of all T-cells. This molecule is used by the T-cell for specific recognition of MHC-associated peptide antigens, discussed in Chapter 12.