What is the optimal pH range for antigen-antibody reactions?

The optimal pH range for antigen-antibody reactions is generally around 6.5 to 7.5. This range is considered neutral to slightly basic, which is ideal for maintaining the stability and functionality of proteins involved in these interactions. Antibodies and antigens, which are typically proteins, have specific three-dimensional structures that can be sensitive to changes in pH. At the optimal pH, hydrogen bonding, hydrophobic interactions, and ionic attractions between the antigen and antibody are maximized, promoting effective binding.

If the pH falls below or rises above this range, it can lead to denaturation or conformational changes in the antibodies or antigens, thus impairing their ability to interact correctly. Consequently, this neutral pH range strikes a balance that supports the necessary biochemical interactions while minimizing potential protein instability.