Question

Oligomeric peptides function as T-cell epitopes. is it true or false? and why?​

Answer 1

Answer:

Adaptive immunity is mediated by T- and B-cells, which are immune cells capable of developing pathogen-specific memory that confers immunological protection. Memory and effector functions of B- and T-cells are predicated on the recognition through specialized receptors of specific targets (antigens) in pathogens. More specifically, B- and T-cells recognize portions within their cognate antigens known as epitopes. There is great interest in identifying epitopes in antigens for a number of practical reasons, including understanding disease etiology, immune monitoring, developing diagnosis assays, and designing epitope-based vaccines. Epitope identification is costly and time-consuming as it requires experimental screening of large arrays of potential epitope candidates. Fortunately, researchers have developed in silico prediction methods that dramatically reduce the burden associated with epitope mapping by decreasing the list of potential epitope candidates for experimental testing. Here, we analyze aspects of antigen recognition by T- and B-cells that are relevant for epitope prediction. Subsequently, we provide a systematic and inclusive review of the most relevant B- and T-cell epitope prediction methods and tools, paying particular attention to their foundations.

Answer 2

Answer:

T-cells do not recognize any random antigen. They interact with the part of antigen which is presented by a special molecule called MHC (Major Histocompatibility Complex) on antigen-presenting cells or APCs. So oligomeric peptides alone can't function as T-cell epitopes.

Explanation:

• Epitopes are the sites or region on the antigen which is recognized by the antibodies as foreign bodies. They are also known as antigenic determinants and are immunologically active regions that bind to the antigen-specific membrane receptors on the cells of the immune system or secreted antibodies.
• T-cell receptors cannot bind to free peptides or antigens.
• The antigenic peptide which is processed by the APC or nucleated cells interacts with the T-cell receptor and a trimolecular complex formed- class II MHC+ peptide + T-cell receptor.
• Hence, oligomeric peptides can't function alone as T-cell epitopes. These epitopes are processed and presented to the T-cells via MHC I and MHC II complex.