June 09-41-2.indd - Kma.org.kw

112KUWAIT MEDICAL JOURNAL June 2009Original ArticleExpression of NC-2 Receptor on MCL Cells and ItsNatural Cytotoxicity Against Cancer CellsHedayatollah Shirzad, Behnam Zamanzad, Ghorbanali ShahabiDepartment of Microbiology and Immunology, Cellular and Molecular Research Center, Shahrekord University ofMedical Sciences, Shahrekord, IranABSTRACTKuwait Medical Journal 2009; 41 (2): 112-116Objectives: To identify the expression of NC-2 onan interleukin-3 dependent mast cell line (MCL) andinvestigate the activity of this receptor against tumorcellsDesign: Laboratory studySetting: Cellular and Molecular Center, Shahrekord, IranSubjects and Methods: The MCL cells were stained withD9 monoclonal antibody (anti-NC-2) and analysed by flowcytometry. This was confirmed by immunoperoxidasestaining. The cytotoxicity assay was performed to showthe cytotoxic activity of MCL cells against 51Cr-labelledWEHI-164 tumor cells.Intervention: The expression of NC-2 on MCL cells, andthe anti-tumor activity of this receptor were investigated.Main Outcome Measure(s): Flow cytometric analysisand in vitro experiments were performed for showing theactivity of NC-2 against cancer.Results: NC-2 receptor was expressed on more than95% of MCL cells. Pretreatment with D9 monoclonalantibody resulted in about 63% reduction in naturalcytotoxicity of MCL cells against WEHI-164 tumortarget cells.Conclusions: NC-2 is also one of the receptors expressedon MCL and utilized for WEHI-164 tumor cell killing.KEY WORDS: monoclonal antibody, natural cytotoxicity, receptor, tumorINTRODUCTIONNatural cell-mediated cytotoxicity (NCMC) isa major component of innate cellular immunityagainst cancer and infection. NCMC is mediatedprimarily by leucocytes which perform naturalkilling (NK) and natural cytotoxicity (NC) withoutthe requirement for prior sensitization and there isno immunological memory associated with this typeof responses. This mechanism is characteristicallyand functionally different from the cell-mediatedcytotoxicity of cytotoxic T lymphocytes. Cellsmediating NK and NC are two distinct andprobably related NCMC effector mechanismswhich are distinguishable from each other by thetime differences required to mediate their killing, aswell as the kinetics of their appearance and declinein mice [1-3] .Natural killer (NK) cells belong to an importantlymphocyte population that eliminates transformedcells and invading viral pathogens without any priorsensitization. These cells possess not only naturalkilling activity against non-self and altered-self cellsbut also exhibit cytokine production and antibodydependentcell-mediated cytotoxicity (ADCC) [4] .It has been shown that NK cells might not servemerely as cytotoxic lymphocytes combating viralpathogens and malignant tumors, but must also beconsidered as important immunoregulatory cellswith a significant influence on adaptive immunity [5] .The effector’s functions of NK cells are regulated byintegrated signals across the array of stimulatoryand inhibitory receptors engaged upon interactionwith target cell surface ligands [6] . Intensive researchduring the 1990s has defined a large number ofactivating and inhibitory receptors [7-9] . NK cellsare heterogeneous in their receptor repertoire,in the sense that different cells express differentcombinations of activating and inhibitory receptors.In addition, a functional heterogeneity is emerging,at least in the human. The majority of blood NK cellsexpress moderate levels of CD56 in combination withvarious molecules of killer cell immunoglobulinreceptor (KIR) family [10] . In addition, there is a smallsubpopulation of blood NK cells that express highlevels of CD56 in combination with the inhibitoryreceptor NKG2A, and no receptors of the KIR family.This subset has low perforin levels and seems to bespecialized for high cytokine secretion rather thanAddress correspondence to:Dr Behnam Zamanzad, MD, PhD, Departement of Microbiology and Immunology, Shahrekord University of Medical Sciences, Shahrekord, Iran.Fax: +98-381-333491, E-mail: Bzamanzad@yahoo.com