Brief Det~nitivc Report Murine Pancreatic Fl-cells Express H-2k and H-2d but Not Ia Antigens*

Allograft survival is marked ly prolonged by a var iety of p re t rea tment regimens such as lymphocytotoxie drugs, i rradiat ion, a n d / o r cul ture of donor tissue. These procedures, initially appl ied to the thyroid (1, 2) and subsequent ly to islets o f Langerhans , stress the role of passenger lymphoid cells in allograft rejection. Marked prolongat ion of islet allograft survival (>100 d) across a major his toeompat ibi l i ty barr ier has recently been accompl ished in rats by in vitro cul ture of islets at 24°C for 7 d before t ransplanta t ion in conjunct ion with a single injection of rabbi t ant i rat lymphocyte serum into the recipient (3, 4). Successfully t ransplanted islets were p rompt ly rejected after injection of donor lymphoid cells (5). Thus, cul tured islets, a l though deficient in the capaci ty to s t imulate allograft rejection, are capab le of serving as the targets o f an established response. A recent s tudy with immunofer r i t in labeling of fixed and trypsin-dispersed mouse islet cells concluded that these cells lack all H-2 antigens (6). Because only bra in and ova of adul t animals have been shown to lack H-2 antigens completely, we have repeated these studies with a more convent ional assay for h is tocompat ibi l i ty antigens. 20 ant i -H-2 and ant i Ia sera have been tested on islet cells from mice of three different H-2 haplotypes by direct microcytotoxici ty and by absorpt ion. Con t ra ry to the results of Parr (6), we find bo th H 2 K and H-2D, but not Ia, antigens on the major i ty of islet cells.