Immunological properties of subcellular rat lymphocyte preparations. Primary allogeneic stimulation in vitro by fractions containing Ia (RT1-B), but not RT1-A antigens.

Open Access
Publisher Website
Google Scholar
Abstract
Rat thymocyte membrane fractions were prepared which exhibit strain-specific primary mixed-lymphocyte reaction (MLR)-stimulating and Ia [immune response-associated] (RT1-B) antigenic properties. These preparations lack the antigenicity of classical, serologically-defined RT1-A (Ag-B) antigens, as defined by in vitro serologic assays. After immunization of allogeneic hosts, specific anti-Ia and MLR-blocking antibodies, but not anti-AgB, alloantibodies were elaborated. Thymidine suicide experiments showed that the same clones respond to whole cells and the fragments made from those cells, and the response segregates appropriately in F2 progeny as a major histocompatibility complex (RT1)-linked phenomenon. Hence, it is possible to generate Ia-related allogeneic helper signals in primary, as well as secondary, in vitro responses, using subcellular membrane fragments that have restricted expression of RT1-B-, but not RT1-A-, encoded antigens.