Powerful jets of radiation and particles emitted from the super-massive black holes residing in the
centres of some active galactic nuclei (AGNs) can travel undisrupted over kpc scales. The radio and
optical observations of the large-scale jets and theoretical studies from MHD simulations suggest
a radially stratified structure of relativistic jets. In this scenario, a fast, low-density component of
the jet flow, called the spine, is surrounded by a slow, denser plasma fluid called the sheath. The
spine-sheath boundary layers formed in the relativistic jets of AGNs or gamma-ray bursts (GRBs)
can be conducive to efficient particle acceleration. We study the self-generated magnetic field
and particle acceleration in such shear boundary layers (SBLs) using 2D particle-in-cell (PiC)
simulations. We also present the self-consistent calculation of the radiation spectrum produced
by inverse Compton scattering of relativistic electrons in an external soft photon field.