Final answer:
The claim that antibodies can only recognize 3D conformational epitopes is false. Antibodies can detect both linear and conformational epitopes, contributing to the efficiency of the immune system by their vast diversity and potential for cross-reactivity.
Step-by-step explanation:
The statement that antibodies can only recognize 3D (conformational) epitopes is false. Antibodies can recognize both 3D conformational epitopes and linear epitopes that are present in the primary sequence of proteins. Epitopes are the specific parts of an antigen that antibodies bind to, and they can be composed of a sequence of amino acids in a protein (linear epitopes) or a three-dimensional structure formed by protein folding (conformational epitopes).
The human immune system is capable of generating a vast diversity of antibodies. This is possible because of the genetic mechanisms that produce a multitude of various antibody molecules, far exceeding the number of genes dedicated to encoding them. This diversity of the antibody repertoire is due to processes such as somatic hypermutation and gene segment recombination in B cells, not post-translational modifications.
Furthermore, cross-reactivity of antibodies can occur when an antibody binds to an epitope on a different antigen that closely resembles the one it was originally produced to target. This ability contributes to the versatility and efficiency of the immune response by allowing single antibodies to recognize and bind to multiple antigens with similar epitope structures.