Question

MHC molecules have promiscuous binding specificity. This means that ________?

1) They can bind to multiple different antigens
2) They can only bind to a specific antigen
3) They can bind to both self and non-self antigens
4) They can only bind to self antigens

Answer 1

MHC molecules exhibit promiscuous binding specificity, meaning they can bind to multiple different antigens. MHC I presents self and non-self antigens for cellular immunity, while MHC II presents non-self pathogen antigens for initial T cell activation, thus providing adaptability to the immune system.

Step-by-step explanation:

MHC molecules have promiscuous binding specificity. This means they can bind to multiple different antigens. This characteristic is crucial for the function of MHC molecules in the immune system. Both MHC I and MHC II classes present antigens, but they differ in which cells express them and the type of antigens they present.

MHC I molecules are found on all nucleated cells and are responsible for presenting both normal 'self' antigens and abnormal or 'non-self' pathogen antigens to effector T cells, which are involved in cellular immunity. In contrast, MHC II molecules are only found on professional antigen-presenting cells such as macrophages, dendritic cells, and B cells, and they are involved in presenting abnormal or non-self pathogen antigens for the initial activation of T cells.

The capacity of MHC molecules to present a wide variety of antigens is vital for the immune system to recognize and respond to the diverse array of pathogens encountered by an organism. The promiscuous nature of MHC molecules allows the immune system to be adaptable and respond effectively to various pathogens.