Regulatory potential of fever-range whole body hyperthermia on Langerhans cells and lymphocytes in an antigen-dependent cellular immune response

The febrile response is one of the most common features of infection and in flammation. However, temperature is rarely a variable in experimental immun ological investigations. To determine whether the thermal microenvironment has any immunoregulatory potential in an Ag-dependent response, we applied a mild fever-range whole body hyperthermia (FR-WBH) protocol to BALB/c mice experiencing the contact hypersensitivity (CHS) reaction. We observed that the timing of this FR-WBH treatment relative to the different phases of th e CHS response was crucial to the outcome. FR-WBH treatment before sensitiz ation with a 0.5% FITC solution resulted in a depressed CHS response. This appears to be due to direct effects of FR-WBH on epidermal Langerhans cell trafficking to the draining lymph nodes. In contrast, application of FR-WBH directly after application of the elicitation dose of FITC solution result ed in an enhanced reaction. This result correlates with increased homing of lymphocytes to the site of elicitation. Overall, these data have important implications regarding the role of thermal changes experienced during infe ction and the clinical use of FR-WBH relative to immunotherapeutic strategi es.