The immune system is comprised of cells and molecules whose collective and coordinated response to the introduction of foreign substance is referred to as the immune response. Defense against microbes is mediated by the early reaction (innate immunity) and the late response (adaptive immunity). Innate immunity consists of the epithelial barrier, phagocytes, complement and natural killer cells. Adaptive immunity, a more complex defense reaction, consists of activation of later-developed lymphocytes that, when stimulated by exposure to infectious agents, increase in magnitude and defensive capabilities with each successive exposure. In this review we discuss recent advances in important primary immune deficiency disorders of innate immunity (chronic granulomatous disease, leukocyte adhesion deficiency) and adaptive immunity (severe combined immune deficiency, Wiskott-Aldrich syndrome).
Adaptive Immunity ; Complement System Proteins ; Immune System ; Immunity, Innate ; Killer Cells, Natural ; Leukocytes ; Lymphocytes ; Phagocytes

In the early host defense system, effector function of natural killer (NK) cells results in natural killing against target cells such as microbe-infected, malignant, and certain allogenic cells without prior stimulation. NK cell cytotoxicity is selectively regulated by homeostatic prevalence between a repertoire of both activating and inhibitory receptors, and the discrimination of untransformed cells is achieved by recognition of major histocompatibility complex (MHC) class I alleles through inhibitory signals. Although it is well known that the bipotential T/NK progenitors are derived from the common precusor, functional mechanisms in terms of the development of NK cells remain to be further investigated. NK cells are mainly involved in innate immunity, but recent studies have been reported that they also play a critical role in adaptive immune responses through interaction with dendritic cells (DC). This interaction will provide effector functions and development of NK cells, and elucidation of its precise mechanism may lead to therapeutic strategies for effective treatment of several immune diseases.
Adaptive Immunity* ; Alleles ; Dendritic Cells ; Discrimination (Psychology) ; Homicide ; Immune System Diseases ; Immunity, Innate ; Killer Cells, Natural* ; Major Histocompatibility Complex ; Prevalence

The liver has been characterized as a frontline lymphoid organ with complex immunological features such as liver immunity and liver tolerance. Liver tolerance plays an important role in liver diseases including acute inflammation, chronic infection, autoimmune disease, and tumors. The liver contains a large proportion of natural killer (NK) cells, which exhibit heterogeneity in phenotypic and functional characteristics. NK cell activation, well known for its role in the immune surveillance against tumor and pathogen-infected cells, depends on the balance between numerous activating and inhibitory signals. In addition to the innate direct "killer" functions, NK cell activity contributes to regulate innate and adaptive immunity (helper or regulator). Under the setting of liver diseases, NK cells are of great importance for stimulating or inhibiting immune responses, leading to either immune activation or immune tolerance. Here, we focus on the relationship between NK cell biology, such as their phenotypic features and functional diversity, and liver diseases.
Adaptive Immunity ; Animals ; Autoimmune Diseases ; immunology ; Humans ; Immune Tolerance ; Immunity, Innate ; Killer Cells, Natural ; immunology ; Liver Diseases ; immunology ; Mice

BACKGROUND: Chronic pain reportedly exerts complex effects on immune function. Natural killer (NK) cells are lymphocytes that play a critical role in cellular and innate immunity. This study examined changes in the subset populations and cytotoxic activity of peripheral blood NK cells in patients with chronic pain. METHODS: Thirty patients with chronic moderate-to-severe pain (group P) and age-matched pain-free subjects (group NoP) were enrolled. Peripheral whole blood was analyzed for the percentage and expression of NK cell surface markers (CD56 and CD16) by flow cytometry. Cytotoxic activity was assayed by evaluating CD69 expression on CD3−/CD56+NK cells. RESULTS: The percentage of NK cells among total lymphocytes was not significantly different between groups P and NoP (16.3 ± 9.3 vs. 20.2 ± 10.5%). Likewise, the percentages of two major NK cell subsets, CD56bright and CD56dim, were also not significantly different between the two groups. However, the percentage of CD56bright/CD16+ subset, was slightly but significantly increased in group P (1.0 ± 0.9%; P < 0.01) compared with group NoP (0.5 ± 0.6%). The cytotoxicity of NK cells was not different between the two groups, showing similar CD69 expression (P vs. NoP = 29.2 ± 15.2 vs. 32.0 ± 15.0%). These findings were not influenced by pain intensity, opioid use, or disease causing pain in group P. CONCLUSIONS: NK cell cytotoxic activity and major subset populations, with the exception of an increased percentage of the CD56bright/CD16+ subset, are not significantly altered in patients with chronic severe pain.
Chronic Pain ; Flow Cytometry ; Humans ; Immunity, Innate ; Killer Cells, Natural ; Lymphocytes

Natural Killer (NK) cells are the third population of lymphocyte in the mononuclear cell compartment that triggers first-line of defense against viral infection and tumor transformation. Historically, NK cells were thought of as components of innate immunity based on their intrinsic ability to spontaneously kill target cells independent of HLA antigen restriction. However, it is now clear that NK cells are quite sophisticated and use a highly specific and complex target cell recognition receptor system arbitrated via a multitude of inhibitory and activating receptors. Killer cell immunoglobulin-like receptors (KIR) are the key receptors of human NK cells development and function. To date, fourteen distinct KIRs have been identified: eight are inhibitory types, and six are activating types. The number and type of KIR genes present varies substantially between individuals. Inhibitory KIRs recognize distinct motifs of polymorphic HLA class I molecules. Upon engagement of their specific HLA class I ligands, inhibitory KIR dampen NK cell reactivity. In contrast, activating KIRs are believed to stimulate NK cell reactivity when they sense their ligands (unknown). KIR and HLA gene families map to different human chromosomes (19 and 6, respectively), and their independent segregation produces a wide diversity in the number and type of inherited KIR-HLA combinations, likely contributing to overall immune competency. Consistent with this hypothesis, certain combinations of KIR-HLA variants have been correlated with susceptibility to diseases as diverse as autoimmunity, viral infections, and cancer. This review summarizes our emerging understanding of KIR-HLA diversity in human health and disease.
Autoimmunity ; Chromosomes, Human ; Humans ; Immunity, Innate ; Killer Cells, Natural ; Ligands ; Lymphocytes ; Receptors, KIR

Asthma is a complex and heterogeneous disease with several phenotypes. Most studies have focused on allergic asthma associated with allergen sensitization and adaptive immunity. On the other hand, nonallergic asthma is associated with a number of environmental factors such as infection, air pollution, or obesity, and requires innate immunity rather than adaptive immunity. In the lung, a number of innate immune cells and mechanisms have evolved to lead lung inflammation and asthma. These innate mechanisms include innate cytokines and various innate cells, including innate lymphoid cells, natural killer cells, as well as gammadelta T cells, which together produce a wide range of cytokines, independent of adaptive immunity and conventional antigens. Here, we review the most recent works regarding innate immune cells and the mechanisms underlying their role in asthma.
Adaptive Immunity ; Air Pollution ; Asthma* ; Cytokines ; Hand ; Immunity, Innate* ; Killer Cells, Natural ; Lung ; Lymphocytes ; Natural Killer T-Cells ; Obesity ; Phenotype ; Pneumonia ; T-Lymphocytes

Inbred mice, a systematically developed homogeneous animal, have been developed to maintain experimental reproducibility and to minimize experimental variables in animal-based studies. In particular, C57BL/6 mice are frequently used in experiments into immunology and antitumor activity experiments. This study was compared the immunological characteristics of C57BL/6NKorl, a Korean developed experimental animal resource, with those of two other C57BL/6N substrains. Mouse body, thymus, and spleen weights in C57BL/6NKorl were not significantly different from those of the other two C57BL/6N substrains. Among the three substrains, there was no difference in the distribution of T and B cells, which are lymphocytes involved in adaptive immunity, and no difference in NK cells related to innate immunity. Results for macrophages and granulocytes, which have roles in innate immunity, were similar in all three substrains. In order to investigate the expressions of major histocompatibility complex (MHC) molecules and allogenic antigens, splenocytes were separated from obtained spleen and analyzed by using flow cytometry. MHC class I and II molecules, which are important during self/non-self-discrimination, were similar in the three substrains. In addition, expression of alloantigen involved in allografts showed similar results in the three substrain. Thus, the results of this study provide strong evidence that C57BL/6NKorl is immunologically similar to two other C57BL/6N substrains.
Adaptive Immunity ; Allergy and Immunology ; Allografts ; Animals ; B-Lymphocytes ; Flow Cytometry ; Granulocytes ; Immunity, Innate ; Isoantigens ; Killer Cells, Natural ; Lymphocytes ; Macrophages ; Major Histocompatibility Complex ; Mice* ; Spleen ; Thymus Gland ; Weights and Measures

BACKGROUND: Natural killer (NK) cells are CD3 (-) CD14 (-) CD56 (+) lymphocytes. They play an important role in the body's innate immune response. They can induce spontaneous killing of cancer cells or virus-infected cells via the Fas/Fas ligand or the granzyme/perforin systems. The corticotropin-releasing hormone (CRH) is an important regulator for the body's stress response. It promotes proliferation and migration of various cancer cells through the CRH type 1 receptor under stress, and also inhibits NK or T cell activity. However, the relationship of CRH and NK cell migration to the target has not been confirmed. Herein, we study the effect of CRH on NK cell migration. METHODS: We used the human NK cell line, NK-92MI, and tested the expression of CRH receptor type 1 on NK-92MI by RT-PCR. This was to examine the effect of CRH on tumor and NK cell migration, thus NK cells (NK-92MI) were incubated with or without CRH and then each CRH treated cell's migration ability compared to that of the CRH untreated group. RESULTS: We confirmed that CRH receptor type 1 is expressed in NK-92MI. CRH can decrease NK cell migration in a time-/dose-dependent manner. CONCLUSION: These data suggest CRH can inhibit NK cell migration to target cells.
Cell Movement* ; Corticotropin-Releasing Hormone* ; Homicide ; Humans* ; Immunity, Innate ; Killer Cells, Natural* ; Lymphocytes ; Receptors, Corticotropin-Releasing Hormone

Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) are the most common cause of genital ulceration in humans worldwide. Typically, HSV-1 and 2 infections via mucosal route result in a lifelong latent infection after peripheral replication in mucosal tissues, thereby providing potential transmission to neighbor hosts in response to reactivation. To break the transmission cycle, immunoprophylactics and therapeutic strategies must be focused on prevention of infection or reduction of infectivity at mucosal sites. Currently, our understanding of the immune responses against mucosal infection of HSV remains intricate and involves a balance between innate signaling pathways and the adaptive immune responses. Numerous studies have demonstrated that HSV mucosal infection induces type I interferons (IFN) via recognition of Toll-like receptors (TLRs) and activates multiple immune cell populations, including NK cells, conventional dendritic cells (DCs), and plasmacytoid DCs. This innate immune response is required not only for the early control of viral replication at mucosal sites, but also for establishing adaptive immune responses against HSV antigens. Although the contribution of humoral immune response is controversial, CD4+ Th1 T cells producing IFN-gamma are believed to play an important role in eradicating virus from the hosts. In addition, the recent experimental successes of immunoprophylactic and therapeutic compounds that enhance resistance and/or reduce viral burden at mucosal sites have accumulated. This review focuses on attempts to modulate innate and adaptive immunity against HSV mucosal infection for the development of prophylactic and therapeutic strategies. Notably, cells involved in innate immune regulations appear to shape adaptive immune responses. Thus, we summarized the current evidence of various immune mediators in response to mucosal HSV infection, focusing on the importance of innate immune responses.
Adaptive Immunity* ; Dendritic Cells ; Herpesvirus 1, Human ; Humans ; Immunity, Humoral ; Immunity, Innate ; Interferon Type I ; Killer Cells, Natural ; Mucous Membrane ; Simplexvirus* ; Social Control, Formal ; T-Lymphocytes ; Toll-Like Receptors ; Ulcer ; Viral Load

BACKGROUND: Millions of people in the world are suffering from atopic dermatitis (AD), which is a chronic inflammatory skin disease triggered by Th2 immune responses. The NC/Nga mouse is the most extensively studied animal model of AD. Like human AD, NC/Nga mice demonstrate increased levels of IgE, a hallmark of Th2 immune responses. Adaptive immunity cannot be generated without help of innate immunity. Especially natural killer T (NKT) cells and marginal zone B (MZB) cells have been known to play important roles in linking innate immunity to adaptive immunity. METHODS: Through flow cytometric analysis and ELISA assay, we investigated whether these lymphocytes might be altered in number in NC/Nga mice. RESULTS: Our data demonstrated that the number of NKT cells was reduced in NC/Nga mice and IFNgamma production by NKT cells upon alpha-GalCer stimulation decreased to the levels of CD1d KO mice lacking in NKT cells. However, reduction of NKT cells in NC/Nga mice was not due to CD1d expression, which was normal in the thymus. Interestingly, there was a significant increase of CD1d(high)B220+ cells in the spleen of NC/Nga mice. Further, we confirmed that CD1d(high)B220+ cells are B cells, not dendritic cells. These CD1d(high)B220+ B cells show IgM(high)CD21(high)CD23low, a characteristic phenotype of MZB cells. CONCLUSION: We provide the evidence that there are decreased activities of NKT cells and increased number of MZB cells in the NC/Nga mice. Our findings may thus explain why NC/Nga mice are susceptible to AD.
Adaptive Immunity ; Animals ; B-Lymphocytes* ; Dendritic Cells ; Dermatitis, Atopic ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunity, Innate ; Immunoglobulin E ; Lymphocytes ; Mice* ; Models, Animal ; Natural Killer T-Cells ; Phenotype ; Skin Diseases ; Spleen ; Thymus Gland