Answer :
B cell receptors (BCRs) and T cell receptors (TCRs) can distinguish one pathogen from another by recognizing macromolecules unique to a given pathogen. BCRs can recognize antigens without MHCs, while TCRs only bind to peptide epitopes presented on MHCs by antigen-presenting cells. So, the correct option is b. Macromolecules that are unique to a given pathogen.
B cell receptors (BCRs) and T cell receptors (TCRs) can distinguish one pathogen from another because they recognize macromolecules that are unique to a given pathogen. BCRs can bind to antigens on free pathogens or their soluble components, recognizing a variety of molecular classes such as proteins, polysaccharides, and lipopolysaccharides without the need for presentation by Major Histocompatibility Complexes (MHCs). Meanwhile, TCRs require antigens to be presented on MHCs, as they can only bind to peptide epitopes when presented by antigen-presenting cells like dendritic cells, macrophages, and B-lymphocytes. Both types of receptors are crucial for the immune system's ability to specifically recognize and respond to pathogenic invaders.
While macrophages and dendritic cells utilize pattern recognition receptors (PRRs) to detect pathogen-associated molecular patterns (PAMPs) which are nonspecific, BCRs and TCRs are specifically tailored to recognize the unique structures of antigens, enabling precise targeting of pathogens. So, the correct option is b. Macromolecules that are unique to a given pathogen.