In the tissue fluids cells of the second line of innate defense such as this dendritic cell carry out surveillance for anything that appears foreign Dendritic cells engulf the rhinovirus within and endosome The endosome fuses with a lisosome whose enzymes digest the rhinovirus The resulting rhinovirus fragments are called epitopes The dendritic cell then attaches the rhinovirus epitopes to presentation molecules called MHC-II This complex folds outwards so that it sits on the outside of the dendritic cell membrane The dendritic cell then enters a lymphatic vessel and travels to a nearby lymph node Here the dendritic cell part of the innate defenses encounters a helper T-cell which is part of the adaptive defenses The T-cell receptor or TCR of this helper T-cell recognize the rhinovirus epitope while the CD4 glycoprotein associated with the TCR recognize the MHC-II The dendritic cell then stimulates activation of this helper T-cell
