Serological and Immunogenic Activity of Soluble Mouse Transplantation Antigens Controlled by the H -2 Locus

The solubilization and partial purification of mouse transplantation antigens were monitored by (1) anin vitro assay for alloantigenic specificities and (2) anin vivo assay for transplantation antigens controlled by theH -2 histocompatibility locus. Antigens from A/J mice were solubilized by papain and fractionated on a Sephadex G-150 column. The eluate showed a 280 nm absorbance peak (F1 ) in the excluded volume and two peaks (F2 and F3 ) in the included volume. H-2 specificities 1, 3, 4, 5, 11, 23, and 28 were confined to a single peak in the F2 fraction.Fractions F1 , F2 , and F3 , were tested for their ability to accelerate skin graft rejection in noncoisogenic strains which differ at bothH -2 andnon-H -2 loci, and coisogenic strains which differ only at theH -2 locus. All fractions produced significant acceleration of graft rejection in the noncoisogenic strains, but only fraction F2 produced significant acceleration in the coisogenic strains. These findings indicate that H-2 transplantation antigens detected by ourin vivo assay, and H-2 alloantigenic specificities detected by ourin vitro assay are solubilized by papain and are eluted in the same peak during Sephadex fractionation.