Conditioning the elevation of body temperature, a host defensive reflex response

Area of Science:

• Immunology
• Neuroscience
• Behavioral Science

Background:

• Host defense mechanisms, including natural killer (NK) cell activity, cytotoxic lymphocyte (CTL) activity, antibody production, and elevated body temperature (TR), are crucial for survival.
• These responses are typically considered innate but may possess a capacity for learned associations.

Purpose of the Study:

• To investigate the conditionability of host defense responses, specifically elevated body temperature (TR).
• To establish a single-trial association paradigm for conditioning defensive reflex responses.
• To explore the potential for simultaneous conditioning of multiple defensive responses.

Main Methods:

• BALB/c mice were conditioned by exposing them to camphor odor for 1 hour, followed by an intraperitoneal injection of the pyrogen poly I:C (20 μg).
• Control groups received either poly I:C injection without odor exposure or a saline injection.
• Conditioned and control groups were re-exposed to the conditioned stimulus (camphor odor) on days 2 or 3.

Main Results:

• Mice in the conditioned group exhibited an elevation in body temperature (TR) upon re-exposure to the camphor odor.
• Control groups (non-conditioned and saline controls) did not show a significant elevation in body temperature.
• Previous studies using the same paradigm successfully conditioned natural killer (NK) cell responses.

Conclusions:

• Elevated body temperature (TR) is a conditionable host defense response.
• A single-trial association paradigm can be used to condition defensive reflex responses.
• These findings suggest that multiple host defense mechanisms may be simultaneously conditionable, potentially conferring a survival advantage.