Trans vivo analysis of human delayed-type hypersensitivity reactivity

Area of Science:

• Immunology
• Cell-mediated immunity
• Hypersensitivity reactions

Background:

• Monitoring delayed type hypersensitivity (DTH) is clinically important for assessing cell-mediated immunity.
• Traditional DTH skin tests pose risks, such as sensitizing transplant patients to donor antigens.
• A safer alternative for DTH assessment is needed in specific clinical scenarios.

Purpose of the Study:

• To develop and validate an alternative method for human DTH testing.
• To enable DTH response monitoring without direct patient exposure to challenge antigens.
• To establish a model for studying in vivo mechanisms of human DTH.

Main Methods:

• Peripheral blood mononuclear cells from human subjects were transferred with specific antigens into naive mice.
• The transfer was performed into the pinnae or footpads of the recipient mice.
• A measurable DTH-like swelling response, termed the 'trans vivo DTH response,' was induced and analyzed.

Main Results:

• The trans vivo DTH response was successfully induced using tetanus toxoid, cytomegalovirus (CMV), and alloantigens.
• Human T cells, antigen, and macrophages were required for swelling responses.
• The observed responses were antigen-specific and dependent on prior antigen sensitization.

Conclusions:

• The trans vivo DTH response assay provides a reliable and simple method for clinical monitoring of DTH.
• This assay avoids direct antigen challenge in patients, mitigating sensitization risks.
• The model facilitates in-depth investigation of the in vivo mechanisms underlying human DTH.