MHC signaling during social communication.

Area of Science:

• Immunology
• Behavioral Ecology
• Genetics

Background:

• The Major Histocompatibility Complex (MHC) has been recognized for its role in immune recognition since the 1950s.
• In the 1970s, research revealed that MHC also functions in social signaling, a discovery initially surprising.
• MHC signaling is now known to occur in vertebrates, influencing behaviors like mate choice, kin recognition, and parent-offspring interactions.

Purpose of the Study:

• To review and organize recent findings on MHC social signaling.
• To discuss four models of MHC signaling: individuality, relatedness, genetic compatibility, and quality.
• To synthesize mechanistic studies and explore the evolutionary origins of MHC's social signaling role.

Main Methods:

• Literature review and synthesis of recent findings.
• Discussion of four non-mutually exclusive models of MHC signaling.
• Analysis of current mechanistic studies on MHC signaling.

Main Results:

• MHC signaling is widespread in vertebrates, influencing diverse social behaviors.
• Key chemical constituents and receptors of MHC signals are being identified.
• Evidence suggests MHC's role in social signaling may predate its immune function.

Conclusions:

• MHC's function in social signaling is conserved across vertebrates, including humans.
• Understanding the molecular basis of MHC signaling allows for sophisticated experimental designs.
• The social signaling role of MHC may be an ancestral trait, predating its adaptive immune function.