The twin research has intrigued researchers since the beginning of scientific research. Are two “identical” twins really identical? Immunologists had their doubts and epigeneticists (those who study epigenome characteristics) as well.
A paper in PNAS by Wang and colleagus from S.D.Boyd’s group at Stanford earlier this year confirms the doubts the immunologist had. They have analyzed the B lymphocyte repertoire in identical twins who had been immunized with the virus Varizella zoster. Being close and sharing sequences, the repertoires against Varizella differed, however. Recombination of light and heavy chains and somatic mutation generated a unique individual pattern, as one would have predicted. The recombination and somatic mutation events are thus, at least partially, independent of the genetic environnement where they take place and thus generate a unique individual repertoire by which the individuum could be recognized.
It is nice that finally evidence for this foreseeable result has been accumulated. Recommended!
Gerald Maurice Edelman died in La Jolla California at the age of 84.
Immunologist worldwide recognize him for his contribution to the antibody enigma. Trained in medicine and chemistry his first publication on antibodies established that these molecules can be subjected to urea and sulfhydryl treatment and yield smaller chains as we know now very well but was new in 1959 when first published. For his work on antibody strucuture which e.g. lead to the first sequence of Ig γ-chain he was awarded the Nobel Prize in 1972 together with Rodney R. Porter.
The antibody enigma was only solved by Susumu Tonegawa who showed that recombination of the same DNA could lead to millions of different mRNAs from which finally antibody molecules are translated. He obtained the Nobel Prize in 1987 as well.
For years it has been known that B lymphocytes express either IgM and IgM/IgD. It was unknown how B cells are triggered to express IgD additionally. A paper in PNAS (doi: 10.1073/pnas.1402739111) now demonstrates that a so far overlooked Zinc-finger protein (ZFP318) is responsible for the alternative splicing in the B cell thus driving expression of IgD.
A paper in Nature:Nature 509, 637–640 (29 May 2014) doi:10.1038/nature13300 describes in detail the complex ways B cells travel betwenn in dark und the light zone during clonal expansion and hypermutation. That is remarkable since the autors use different techniques for the labelling of cells. Aside from methodological point of view this shows complex interactions with T cells as one driving force in this process.