A newly transplanted organ is rejected by the immune system of the host. Which protein is responsible for the rejection

Histocompatibility antigens are encoded on more than 40 loci, but the loci responsible for the most vigorous allograft rejection reactions are on the major histocompatibility complex (MHC).

Explanation:

Transplantation involves transferring from one site to another of cells, tissues or organs, often among people. An organ transplant (eg, kidney, liver, cardiac, lung, or pancreas) from a donor may rectify organ malfunction.

The immune system remains as a standard medical treatment the greatest barrier to transplantation. An effective and intricate mechanism has been evolved in the immune system to fight off invading invaders. These systems also contribute to the refusal of the transplanted bodies that are recognized by the immune system of the receiver as foreign.

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.