Effect of Physical Stress on Immune Function in Cell Lines: B7-2 Molecules Contribute to Augmented Antigen Presentation Induced by Heat Shock

T cell activation occurs following the recognition of MHC II–antigen complexes on antigen-presenting cells (APCs) and in conjunction with binding of costimulatory moleclues such as B7. The heat shock response is characterized by the synthesis of heat shock proteins (Hsp) that can alter normal subcellular regulatory pathways in order to repair stress induced cellular damage. Because Hsps can also contribute to normal cell function, the present studies were initiated to determine whether heat shock could be adapted to alter APC function and thereby increase T cell responses to alloantigen. LB27.4, a B cell APC line, was exposed to hyperthermic or normal temperature conditions and cocultured with the D10.G4 helper T cell line. Our results indicate that heat shock can enhance the ability of APCs to activate T cell function. The costimulatory molecule, B7-2 is responsible, at least in part, for the enhancement of APC function. Increased function occurred concomitantly with synthesis of Hsps. Using a cell line-based model system, these studies suggest one mechanism of immune regulation based on the physiological response to stress, and describe an engineering strategy whereby cellular function can be manipulated by the adaptation of the stress response.