What happens to exogenous antigens during the creation of an MHC class II receptor?

During the creation of an MHC class II receptor, exogenous antigens are taken up by antigen-presenting cells (APCs) through processes such as endocytosis or phagocytosis. Once inside the cell, these antigens undergo digestion. This digestion breaks down the proteins into peptide fragments, which are then loaded onto the MHC class II molecules within specialized cellular compartments known as endosomes or lysosomes.

After this loading occurs, the MHC class II molecules, now bearing the antigenic peptides, are transported to the cell surface. This allows them to be recognized by CD4+ T helper cells, which is a crucial step in initiating a cell-mediated immune response. The presentation of these antigens on MHC class II molecules is essential for the activation of T cells and subsequent adaptive immune responses.

The other choices do not accurately describe the role of exogenous antigens in relation to MHC class II molecules. Replication doesn't occur in this context, as the antigens are not duplicated but rather processed into peptides. Elimination of exogenous antigens from the cell is not the purpose; instead, they are transformed into a format suitable for T cell recognition. While exogenous antigens can stimulate B cell division, this is