The development and differentiation of NK cells are highly noted in recent years.In addition to the peripheral blood,spleen and bone marrow,the liver,lymph nodes and thymus are also considered as important organs for differentiation of NK cell precursors(NKPs).Human NK cell subset CD56bright is enriched in secondary lymphoid tissues and non-lymph tissues;NK subset cell CD56dim can migrate to peripheral inflammatory region.Activating receptors on NK cells include cytokine receptors,integrin receptors,natural cytotoxic receptors,immunoglobulin-like killer receptors,and many new receptors and ligands different from the aforementioned receptor families.In the process of tumor progression,NK cells can directly recognize malignant cells via "internal recognition" and be activated;they can also be activated by accessory cells such as monocytes,macrophages and dentritic cells.DC cells can trigger the activation of NK cells,in which the reverse signal transduction of IL-15R-IL-15 plays an important role.Great progression has been made in NK cell-based immunotherapy of tumor,in particular there are many new ways in NK cell innate recognition-based tumor biotherapy.

Natural killer cells are the key effector cells in innate immune response,playing the role in pathogen clearance and tumor immunosurveillance by cytokine secretion and cytotoxicity.Hematopoietic stem cells go through developmental intermediates to generate mature NK cells under the progressive regulation of extrinsic factors and intrinsic factors.In the past thirty years, great progresses have been made in the developmental progress,niches,regulation of NK cells and the relationship between NK cells and dis-eases.In this review,we will discuss in detail the molecular mechanisms of NK cell development and the diseases caused by functional compromise of NK cells.

Type Ⅱ innate lymphoid cells is an emerging family of innate lymphocytes mainly distributed in mucosal tissues such as the lungs,intestines,skin,etc.These cells are capable of producing Th2-type cytokines including IL-5 and IL-13 in response to IL-25 and IL-33.ILC2s has attracted much attention for its important roles in anti-infection immunity and allergic diseases in respiratory tract.Studies have shown that ILC2s represented a crucial source of Th2-type cytokines and could regulate the adaptive immune response in allergic airway diseases.Meanwhile,ILC2s was able to fulfill vital functions in parasite clearance, anti-virus infection and subsequent tissue repair.Therefore,research in ILC2s phenotype,development and function has great practical significance.This paper reviews the definition, classification, developmental regulation of ILC2s with a particular focus on its role in respiratory mucosal homeostasis and lung-related diseases.

As the passage of environmental atmosphere entering the body,the respiratory tract suffers persistent challenge from foreign substances.The mucosal immune system of the respiratory tract is the main defense line against the invasion of pathogens,which needs to distinguish not only beneficial and detrimental materials but also resident and pathogenic bacteria.Because the knowledge about respiratory mucosal immunity is limited,the immunopathologic mechanisms of related diseases such as asthma,acute lung injury, chronic obstructive pulmonary disease, and respiratory infection need investigation.The study about the immune features of the respiratory tract not only contributes to the prevention and treatment of respiratory disease but also provides ideas for the development and design of new vaccines and medicines.

Natural killer (NK) cells have long been considered the only representative of lymphocyte lineages among the innate immune system ,but recent studies have revealed that several types of innate lymphoid cells ( ILC ) exist in both humans and mice.These newly identified ILC populations were mainly distributed at mucosal barriers ,regardless of their rarity ,they play important roles in the defense against pathogens and in the maintenance of tissue or organ homeostasis .In the early stages of ILC development ,a common ILC lineage-restricted progenitor exists and under the control of different transcription factors ,the progenitor can later give rise to different ILC subsets with distinct phenotypes and functions.Different ILC subsets exhibit distinct cytokine secretion profiles ,based on the categorization of helper T cell subsets , ILC family has been further classified into three groups.The finding of diverse ILC extremely enriches the content of innate immunity ,and also provides new insights into links between innate and adaptive immunity .

We used MTT assay to test the cellular cytotoxicity ( NK, LAK, CTL, Macrophage), cytokine activities ( 1L-1, 1L-2, 1L-6, TNF), proliferation of lymphocytes and chemosensitivity of tumor cells, and compared it with radioactive isotope assay. The results showed that the MTT assay may be used to test the cellular cytotoxicity, cytokine ac-tivity, proliferation of lymphocytes and chemosensitivity of tumor cells. We think it is a simple, rapid, economic and safety method.

Large scale preparation of human IL-2 mRNA was obtained from human spleen cells stimulated with PHA+TPA at the peak of IL-2 mRNA transcription. Full length of IL-2 mRNA was translated in wheat germ extract to produce bioactive IL-2 (tIL-2). The IL-2 mRNA was about 14 S depending on the 7 M Urea-SDS-PAGE, and recovried from gel and translated in vitro. The elute curve of tIL-2 was the same as that of recombinant IL-2 (rIL-2) and natural IL-2 (nIL-2), the molecular weight of tIL-2 was about 14.000 dalton. The translational process of IL-2 mRNA in vitro was inhibited when RNA was cultured with RNase or translated product was cultured with proteinase, proving a standard in-vitro translation.

Under stimulation of PHA,PHA + TPA,or PHA + PTS the time ke-netics of DNA,RNA,protein synthesis and lymphokine secretion by human lymph node cell expressed different responses. The PTS did not increase the DNA and RNA synthesis, but increased the protein synthesis ( 60% ) . TPA increased the RNA synthesis ( 18% ) , therefor increased the protein synthesis ( 40% ) . Both of TPA and PTS increased the production of 5 kinds of lymphokines (IL-1 , IL-2 , IL-3, BCGF, TFNr). We infer that PTS and TPA increase the lymphokine production through different gene regulation. TPA Promotes the translation of lymphokine mRNA。

Promoting effect of panaxatriol ginsenoside ( PTGS ) on inter-leukine-3(IL-3 ) induction of phyto-hemagglutinin ( PHA ) stimulated human lymph node cells was observed. The results showed that PTGS enhanced the IL-3 production on each time of IL-3-induction kinetics, maximally by 30% ( 72h ) . Furthermore, it was observed that IL-3 mRNA from PHA+PTGS-stimulated lymph node cells translated more IL-3 than PHA-stimulated lymph node cells on each time of IL-3 mRNA-induction kinetics, maximally by 40% ( 60h ) , using the methods of wheat germ cell-free in vitro translation system and IL-3 bioassay.

thymus.It is not clear why and how these distribution exist,which is possibly correlated to recruitment,homing,subset,and microenvironment of NK cells in each tissue or organ.