Detective Protein


The fact that our body naturally has the ability to fight against foreign components such as bacteria, virus, pathogens and other micro organisms is interesting. These actions are known as immune responses as the body has a very effective and detailed armory to fight most pathogens and keep us from harm as a result of the presence of these pathogens.

One will wonder on a biochemical level how does our body recognize a treat and how does it handle the treat to prevent it from causing a breakdown of law and order thereby causing diseases. The entire process of immunity (the body’s defense mechanism) is vast and depends on a lot of factors especially the nature and location of the antigen or invader.


In this article we will be looking at a very special class of proteins know as the major histocompatibility complex (MHC) proteins that mediates the identification of self and non-self components of the body.

Like every other class of proteins they have specific function and this class of proteins are very unique as they do the job of an undercover detective that moves around in a casual manner to uncover the presence of bad guys (antigens or pathogens or non-self components in one’s system).


The major histocompatibility complex (MHC) is a set of genes that encodes cell surface molecules which controls a major part of the immune system in all vertebrates by determining histocompatibility. The main function of MHC molecules is to bind to peptide fragments derived from pathogens and display them on the cell surface for recognition by the appropriate T-cells.

I do not intend to bore you with so much terminology, so let us liken their function to another situation we are more familiar with. These group of proteins do the work of an agency that registers citizens and issue out compulsory Original National ID cards to citizens (self components of the body). They also ensure that every citizen wears the ID card on his neck at all times so that when the soldiers on patrol comes around they can easily identify the IDs. These solders on patrol already have special skills to identify an Original National ID and a fake one, making it a very easy and an efficient process for the non-self components to be easily identified and dealt with.

Any cell with an Original ID provided by the MHC proteins is a legal citizen and is unharmed while any cell with a fake National ID is seen as a treat, an invader, a pathogen. The soldiers of the body that responds in this case are the T-cells also known as Lymphocytes (T-cells). These T-cells will bind to the displayed antigen on the surface of the cell and lunch the subsequent immune response as a solder will respond in the arrest of a criminal suspect.