<prompt> HLA-I is present on:All nucleated cellsOnly on cells of immune systemOnly on B cellsOnly on T cells  <response>: Ans. is a i.e., All nucleated cellsRef: Jawetz, 27the, p. 139 HLA class I Ag - present on the surfaces of all nucleated cells. HLA class II Ag - only on cells of immune system macrophages, dendritic cells, activated T cells and B cells. 