Those who have their thyroid removed will need to take thyroid hormone replacement (thyroxine) for the rest of their life. In the past, a healthcare practitioner may have had someone on thyroxine refrain from taking it for up to several weeks prior to thyroglobulin testing. This is because low thyroxine will stimulate the production of TSH and, in turn, this will stimulate the production of thyroglobulin by any remaining normal or cancerous thyroid tissue. Therefore, cessation of thyroxin therapy will make the thyroglobulin test more sensitive, but it often leaves the person being tested with uncomfortable hypothyroid symptoms until testing is completed. A recombinant form of TSH is now available as an alternative. It is used to directly stimulate thyroglobulin production.
Antibody drug development is now a mature field with >60 marketed antibody therapeutics and hundreds more in clinical trials. Indeed, many of the more tractable and better understood targets for the treatment of human diseases have been extensively exploited for antibody drug development. This begs the question, where will new targets for future antibody drugs come from? One possible source of new targets for antibodies is in overcoming major delivery challenges that make some potential therapeutic targets challenging, if not impossible, to reach with conventional approaches. Presentations in this session will focus on three such delivery challenges highlighting basic research trying to understand the problems and translational studies attempting to overcome them.
Each heavy chain has two regions, the constant region and the variable region . The constant region is identical in all antibodies of the same isotype, but differs in antibodies of different isotypes. Heavy chains γ, α and δ have a constant region composed of three tandem (in a line) Ig domains , and a hinge region for added flexibility;  heavy chains μ and ε have a constant region composed of four immunoglobulin domains.  The variable region of the heavy chain differs in antibodies produced by different B cells, but is the same for all antibodies produced by a single B cell or B cell clone . The variable region of each heavy chain is approximately 110 amino acids long and is composed of a single Ig domain.