Abstract: “Adaptive immunity, with its rearranging immunoglobulin and T-cell receptors, has caught most of the attention of current genetic and immunological research and overshadowed the importance of the receptors expressed by cells of the innate immune system. Natural Killer cells have evolved two main receptor systems to carry out their functions, both of them involving activating and inhibitory receptors include members from the Immunoglobulin-like superfamily as well as lectinlike receptors. Killer Immunoglobulin-like receptors (KIR) are polymorphic cell surface molecules present on Natural Killer (NK) cells which recognize classical HLA class I molecules and in doing so provide an alternative means of modulating the immune response to infected or tumoural cells. In this study we did the Separation of Natural killer cells (NK cells) from rat’s blood with the technique of LS column with the help of CD49 markers and Cultured of harvested NK cells in animal cells media (Dulbecco’s Modified Eag”

Keywords: Natural killer cells, Killer immunoglobulin-like receptors, human leukocyte antigen, major histocompatibility complex class I, Dulbecco’s Modified Eagle’s Medium