What is MHC?

MHC can refer to several things, making a specific explanation difficult without more context. It could refer to the Major Histocompatibility Complex, which is a set of genes that code for cell-surface proteins that regulate the immune system. Or it can refer to Mechanical Hardness Conversion (MHC), a method used in materials science or engineering. Finally, it may refer to Mental Health Counselor, a trained professional who helps individuals and groups manage mental and emotional health issues.