Major histocompatibility complex (MHC) proteins are also called human antigens (HLA).

Yes, that's correct. Major Histocompatibility Complex (MHC) proteins are indeed also referred to as Human Leukocyte Antigens (HLA). These proteins play a crucial role in the immune system's function. They are responsible for presenting foreign particles (like bacteria, viruses, etc.) to the immune cells, triggering an immune response. There are two main types of MHC proteins: MHC class I and MHC class II. MHC class I proteins are found on all nucleated cells of the body, while MHC class II proteins are found on certain immune cells like macrophages, dendritic cells, etc.