Long-term expression of an HLA-DQ molecule in the EBV-transformed bare lymphocyte cell line, BLS-1, using a plasmid vector

HLA DQ protein changes the cell surface distribution pattern of HLA proteins as monitored by Förster resonance energy transfer and high-resolution electron microscopy

Peptide presentation by MHC class I and MHC class II molecules plays important roles in the regulation of the immune response. One factor in these displays is the density of antigen, which must exceed a critical threshold for the effective activation of T cells. Nonrandom distribution of MHC class I and class II has already been detected at the nanometer level and at higher hierarchical levels. It is not clear how the absence and reappearance of some protein molecules can influence the nonrandom distribution. Therefore, we performed experiments on HLA II-deficient bare lymphocyte syndrome (BLS1) cells: we created a stable transfected cell line, tDQ6-BLS-1, and were able to detect the effect of the appearance of HLA-DQ6 molecules on the homo and heteroassociation of different cell surface molecules by comparing Förster resonance energy transfer (FRET) efficiency on transfected cells to that on nontransfected BLS-1 and JY human B-cell lines. Our FRET results show a decrease in homoassociation FRET between HLA I chains in HLA-DQ6-transfected tDQ6-BLS-1 cells compared with the parent BLS-1 cell line and an increase in heteroassociation FRET between HLA I and HLA II (compared with JY cells), suggesting a similar pattern of antigen presentation by the HLA-DQ6 allele. Transmission electron microscopy (TEM) revealed that both HLA class I and class II molecules formed clusters at higher hierarchical levels on the tDQ6-BLS-1 cells, and the de novo synthesized HLA DQ molecules did not intersperse with HLA class I islands. These observations could be important in understanding the fine tuning of the immune response.

Diabetes-science, serendipity and common sense

This paper is dedicated to young researchers in diabetes. One such person was Frederick Banting who, with his colleagues, isolated insulin in 1921, saving the lives of literally millions of people. What factors allowed Banting and other scientists to produce work that has immensely benefited the human race? I propose that it is the combination of good scientific background (the 'prepared mind'), commonly some serendipity taken with a good dose of common sense and supplemented by enthusiasm, tenacity and good mentoring, which drives the 'power of observation' and the ability to take forward the good idea. I give examples from history to support this and then discuss some of the 'truths, perspectives and controversies' within the diabetes arena when I first started in diabetes research in the late 1970s. I describe how my appetite was initially 'whetted' for research by moving to an excellent clinical research environment with encouragement to test ideas and controversies initially in a clinical research programme, followed by more scientific/basic research. The work that I performed as a young doctor and research fellow led to a lifelong professional interest in three major areas-causes and interventions for diabetes vascular disease, studies of the molecular genetics of Type 1 and Type 2 diabetes and work on diabetes in different ethnic groups. I provide a summation of my own and other people's work to demonstrate how research can be progressed and lead to patient benefit as well as providing an incredibly rewarding career. I believe that we need to encourage and put more resources into development of young doctors and scientists wishing to undertake research in our discipline. Areas ripe for much-needed clinical research programmes, for example, include work on best practice/provision of health care, application of the evidence base from clinical trials to achieve public health gains, attention to adherence issues and better-tolerated therapies. Most importantly, a greater emphasis on prevention through public health measures and 'buy in' from the whole population is urgently required.