Nature of immunity in the male bovine reproductive tract based upon responses to Campylobacter fetus and Trichomonas fetus.
Explore the source record for details and available documents.
Age Factors↗
SEARCH · Search PubMed
Results for “Immunity, Natural”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
[State of certain indices of natural, nonspecific immunity in workers engaged in the manufacture of neomycin and monomycin].
Women occupied at various stages of neomycin and monomycin production were examined immunologically. The examination revealed insignificant changes in the phagocytic activity of the blood neutrophils, however no relation between the changes level and the level of contact with the antibiotics was observed. Changes in composition of the microflora in the deep skin layers in direction of an increase in the number of pathogenic microbes and a decrease in the bactericidal function of the skin were found in the women occupied at the final stages of the technological process, i.e. drying, packing and control.
Drug Industry↗
["Natural" and "immune" heteroagglutinins in Bufo arenarum Hensel: their fractionation by means of human and pig red cells (author's transl)].
Explore the source record for details and available documents.
ABO Blood-Group System↗
Different action of xenoreactive natural and immune antibodies on functioning cardiomyocytes.
PNAB and IAB have totally different action on BCM. PNAB inhibit the contractile function of BCM by producing a reversible standstill and by disturbing the synchronization of the BCM-monolayer. IAB are cytotoxic and depend on the presence of complement.
Animals↗
The nature of immune complexes in human cancer sera.
Sera from 517 patients with various types of malignancies were assayed for immune complexes (ICs) by the Raji cell radioimmune assay. The incidence of immune complexes in these patients ranged from 16 to 52% as compared to 19% in normal controls. Increases in tumor mass and metastatic disease were associated with high levels of circulating ICs. Immunization of melanoma patients with BCG and tumor-cell vaccine produced an increase in levels of ICs. Cancer sera contained complexes of intermediate size. Tumor antigens and IgG, presumably in the form of complexes, were identified by immunofluorescence and radiolabeled antibody techniques on the surface of Raji cells incubated in ICs-containing cancer sera.
Antigen-Antibody Complex↗
[How to manage vaccinations in the elderly traveler].
Along with the growth of travels, the ageing of the population multiplies the number of older travellers. 13% of travellers could be at least 65 years old. It is admitted that there is no upper age limit to perform immunizations. Immunizations are all the more useful for older people because age generally aggravates infectious diseases. With age the immune response decreases definitely, especially that depending on cellular immunity, as well as the humoral response, as it has been observed with vaccinations against tetanus, flu, pneumococcal infections and hepatitis B. The first series of immunizations could be more affected by age than boosters. But a lot of questions still remain unanswered. Is there a maximum age beyond which the immune response would be unadapted to such an extent that it would be necessary to modify the immunization protocols as well as the periodicity of boosters? 75 years? 80 years? Is this age the same for all individuals? Is that a matter of a lower level of the antibody response, or rather of a slower, delayed response? The planning of older travellers immunizations meets another difficulty: their often vague knowledge of past immunization records and infectious diseases. One is often reduced to conjectures. Thus men, who have served in the army since the beginning of World War II are supposed to have got the first series of immunization against tetanus and diphtheria, but how can we restore their immunity (once we have defined the maximum age) when boosters have been either insufficient or missing? Conversely for women born before 1945, who were probably never immunized, a first series of immunization is warranted. On the other hand, since the immunization against poliomyelitis only came into effect in the sixties, most older adults have never been immunized but have acquired in the past a natural immunity from their contact with wild polio viruses. Naturally acquired antipoliovirus immunity doesn't seem to have decreased with age, unlike antidiphtheria and antitetanus immunity, as shown by recent serologic studies. Thus would a single booster with inactivated polio vaccine be sufficient to reinforce the immunity of most older travellers who have never been immunized? Considering these uncertainties, one could think of carrying out a serologic assessment prior to establishing an immunization program, as it has already been recommended for the immunization against hepatitis A. What would its feasibility be? There are quite a lot of questions to discuss. May this round table help define these questions and specify which investigations would be necessary to solve them, as well as program more rationally the immunizations of the older traveller.
Aged↗
Mutual interference of HIV and natural killer cell-mediated immune response.
Natural killer (NK) cells represent important early effector cells in innate immune defense as they exert their functions without prior sensitization. They participate in regulation of innate and adaptive immune responses and hematopoiesis by producing various cytokines and chemokines. In addition, NK cells lyse virally infected and malignant cells raising them to multifunctional members of the first line of defense. Unlike other lymphocytes they lack specific antigen receptors. They rather bind cells using ubiquitous molecules and communicate via a pattern of receptors specific for MHC-I molecules with their counterparts. In general, successful binding of the receptors delivers an inhibitory signal to NK cells thus sparing the target cell from lysis. In contrast, down-regulated or altered MHC-I expression as frequently observed during virus infection or on malignant cells prevents ligation of inhibitory receptors and MHC-I paralyzing inhibition and thus inducing lysis of the target cell. In human immunodeficiency virus (HIV) infection NK cells are of central importance since they can combat viral infection itself and opportunistic pathogens like fungi and protozoa that usually spread during the course of HIV infection. However, various studies have reported alterations in HIV patients affecting NK cell numbers and functions that might negatively influence course and severity of the disease. This review will focus on the mutual interference of NK cells and the HI virus.
Cytotoxicity, Immunologic↗
Immunity against viruses in chickens after applying natural and synthetic immunity stimulator.
Comparing the action of biotropin, which is a natural immunomodulator, with a synthetic one--levamisole, leads to the conclusion that biotropin acts as a strong stimulator, both of specific humoral immunity, which manifests itself in higher titres of antibodies HI and SN, and of non-specific humoral immunity, whose feature is a higher activity of lysozyme in comparison with the other groups. Similarly, biotropin increases the phagocytal activity of leucocytes, expressed as the phagocytar index and the percentage of non-phagocyting cells, more effectively than levamisole. However, the specific cell immunity, assessed by the BT and LMI tests, was slightly better stimulated by biotropin immediately after infection and by levamisole in the remaining time.
Adjuvants, Immunologic↗
Exercise immunology: neuroendocrine regulation of NK-cells.
Natural immunity, including that of the natural killer (NK) cells, is strongly influenced by physical exercise, but the physiological significance of the reported changes in NK cells after exercise training is as yet unclear. The exercise effect is likely mediated by interactions between the central nervous and endocrine systems. Chronic activation of endogenous opioid systems augments natural cytotoxicity. We have investigated the possible involvement of opioids in the exercise-induced enhancement of NK cell function. The pathways by which the central nervous system may communicate with the periphery include neuroendocrine outflow via the hypothalamic-pituitary-adrenal axis and the autonomic nervous system (ANS) through direct nerve fiber connections with cells or the organs of the immune system. This review will discuss the role of various neuroendocrine factors such as growth hormone, catecholamines and glucocorticoids and the role of the ANS, in particular the sympathetic division, in modulating NK cell function in response to exercise.
Afferent Pathways↗
Role of saliva in tick/host interactions.
Although several hosts mount efficient anti-tick immunity, natural tick/host associations are characterized by inefficient or non-existent anti-tick immunity. The absence of efficient anti-tick immunity in natural hosts could result from either host immune incompetence or the ectoparasite's successful evasion of the host's immune response. In this review I discuss data supporting the immune-evasion hypothesis and discuss its consequences to tick/host interactions.
Animals↗
Natural IgM antibodies: the orphaned molecules in immune surveillance.
Natural IgM antibodies are typical victims of prejudices which originated in the mid 80 s. Over the years, these molecules were considered as the pariahs among the immune competent molecules and their characteristic properties, like low affinity, cross-reactivity and pentameric structure, were assessed as useless, difficult, nebulous, etc. Today, mainly based on a few scientists' persistent work and the key discoveries on innate immune recognition, natural IgM antibodies are "back on stage". Their role in the immune response against bacteria, viruses, fungi and possibly modified self-components as well as in therapy and diagnosis of malignancies is accepted. All the so far negatively judged features are seen in a different light, e.g. low affinity seems to be good for function and does not exclude specificity, and cross-reactivity is no longer judged as unspecific, but instead as a very economic way of immune recognition. And at last, with the use of natural IgM antibodies, a new field of tumor-specific targets has been encountered, the carbo-neo-epitopes. Therefore, by having learned from nature, the renaissance of natural IgM antibodies opens a new area of cancer therapeutics and diagnostics.
Animals↗
Interaction of conjugated linoleic acid, sphingomyelin, and butyrate on formation of colonic aberrant crypt foci and immune functions in rats.
This study was designed to investigate possible additive or synergistic action among sphingomyelin (SPH), cis-9,trans-11-conjugated linoleic acid (CLA), and butyrate (BTY) against colon cancer and modulation of immune functions in vivo in male Sprague-Dawley rats. Each of the 5 groups of rats was fed either 35 mg SPH, 100 mg CLA, or 100 mg BTY/kg body weight, a combination of the 3 compounds at the same doses, or none of the compounds, for 7 wk. Rats were injected with azoxymethane, a colon carcinogen, to induce the formation of aberrant crypt foci, preneoplastic lesions of colon cancer. Parameters measured included number and multiplicity (number of crypts per focus) of aberrant crypts, immune functions such as innate immunity (natural killer cell cytotoxicity), humoral immunity (development of antibodies), and cell-mediated immunity (delayed-type hypersensitivity). Results show that the groups treated with SPH, CLA, and BTY individually had significantly higher natural killer cell (NK) cytotoxicity than the group treated with all compounds. The CLA group also had significantly higher NK activity than the control group. This study shows that the three compounds may not act additively or synergistically either to inhibit the development of aberrant crypts or to enhance immune functions. In fact, exposure to the combined compounds may be antagonistic to enhancement of NK function by the individual chemicals.
Animals↗
Progressive liver injury in chronic hepatitis C infection is related to altered cellular immune response and to different citokine profile.
Natural immune responses, both cellular and humoral, are not capable of terminating HCV infection in most patients. The aim of this study was to evaluate: a) the importance of the immune system in the pathogenesis of chronic HCV infection; b) analysis of successful immunoresponses in persons infected with C virus; c) immuno mechanisms in the progression of hepatic damage; d) different cytokine profiles from patients with persistent and self-limited hepatitis C virus infection; e) development of new antiviral strategies when virus is resistant to interferon treatment. The inadequate T helper1 (Th1) immunity as well as the weak HCV-specific T-cell response at the site of inflammation is associated with failure to clear the virus and a chronic course of disease. The production of interleukin 12 (IL-12) is critical for induction of Th1 immunity, directed towards elimination of intracellular pathogenes and viruses. The core protein of HCV seems to have a suppressive action on IL-12 production at the transcriptional level. The specific Th1 cell defect is correlated with insufficient Th and CTL responses, and lower production of type 1 cytokine (IL-2, IFN-gamma, lymphokine-activated killer cells). Taken together, these results are probably responsible for non-eradication of HCV infection. Particularly the effects of interferon-gamma may include inhibition of HCV virion production by an effect on viral RNA and protein synthesis, enhancement of immune lysis of HCV infected cells, inhibition of hepatic fibrosis by an effect on TGF-beta, and an effect on HCV induced carcinogenesis. These data suggest an HCV-related cellular immune defect in patients with hepatitis C that can be restored in most patients by IL-12. New approaches using a combination of nucleoside analogs or other strategies, such as immune intervention (DNA vaccine, stimulation of the Th1 response) or gene therapy (antisense oligonucleotides dominant negative mutants) should therefore be evaluated in animal models to optimize the current antiviral protocols.
Antibody Formation↗
Complex interactions: the immunogenetics of human leukocyte antigen and killer cell immunoglobulin-like receptors.
The killer cell immunoglobulin-like receptors (KIR) for human leukocyte antigen (HLA) modulate innate and adaptive immunity by controlling effector cells. HLA and KIR are encoded in genomic regions that have complex organization and exhibit exceptional diversity within and among human population groups. This diversity is likely to have arisen to combat a constantly evolving pathogen challenge. Numerous variations influence the expression level or function of KIR molecules and can affect their interaction with HLA, with important implications for the immune response. The functional variety of natural immune responses that are controlled by HLA and KIR interactions is genetically determined and maintained by natural selection.
Animals↗
Effect of micronutrient status on natural killer cell immune function in healthy free-living subjects aged >/=90 y.
BACKGROUND: Natural killer (NK) cells play a role in natural immunity against tumor and infected cells. Advanced aging is associated with functional impairment of NK cells and increased susceptibility to nutritional deficiencies. OBJECTIVE: Our objective was to test whether micronutrient status affects NK cell activity in an older population. DESIGN: The relations between NK cell variables (percentage of leukocytes and cytotoxicity) and blood concentrations of selected micronutrients were studied in 62 healthy, free-living northern Italian subjects (25 men, 37 women) aged 90-106 y. Anthropometric measurements were also made. RESULTS: All subjects were well nourished according to age-specific anthropometric norms but many of them had micronutrient deficiencies. The prevalence of micronutrient deficiency was highest for selenium (in approximately 50% of both sexes), zinc (in 52% of men and 41% of women), and vitamin B-6 (in 40% of men and 59% of women), followed by vitamin A (in 16% of men and 27% of women) and vitamin E, vitamin B-12, and folate (each in <10% of both sexes). Ubiquinone-10 status was inadequate in 40% of women and 24% of men (P = 0.02). The percentage of NK cells was associated with serum zinc (men: r = 0.573, P = 0. 007; women: r = 0.373, P = 0.031) and selenium (women: r = 0.409, P = 0.018) concentrations. In women only, NK cell cytotoxicity at different effector-target cell ratios was positively associated with plasma vitamin E and ubiquinone-10 concentrations (P < 0.05). No significant associations with NK cell variables were found for the other measured nutrients. CONCLUSIONS: The results of this study strengthen the hypothesis that individual micronutrients may affect the number and function of NK cells in old age. The study also confirms the high prevalence of micronutrient deficiencies in healthy and apparently well-nourished persons aged >/=90 y.
Adult↗
Immunthrombocytopenic purpura as a model for pathogenesis and treatment of autoimmunity.
In honour of Professor Rossi's 80th birthday we review the development of our understanding of the immune and auto-immune nature of the pathogenesis of immune thrombocytopenic purpura (ITP). The immune aspects have been documented by postviral alterations of the cellular and humoral immune system, by new methods of specific auto-antibody detection against platelet glycoproteins and by the therapeutic effect of administering immunoglobulin concentrate from healthy blood donors. The various possible mechanisms of action of immunoglobulin treatment have led to use of this treatment as an alternative for other immune-related disorders. The treatment of severe chronic ITP in children, however, remains unsatisfactory. With a new international clinical and laboratory study of children and adolescents with early chronic ITP we are continuing the investigation of the pathogenesis and treatment of ITP.
Antibody Formation↗
Phylogenetic aspects of the complement system.
During evolution two general systems of immunity have emerged: innate or, natural immunity and adaptive (acquired), or specific immunity. The innate system is phylogenetically older and is found in some form in all multicellular organisms, whereas the adaptive system appeared about 450 million years ago and is found in all vertebrates except jawless fish. The complement system in higher vertebrates plays an important role as an effector of both the innate and the acquired immune response, and also participates in various immunoregulatory processes. In lower vertebrates complement is activated by the alternative and lectin pathways and is primarily involved in the opsonization of foreign material. The Agnatha (the most primitive vertebrate species) possess the alternative and lectin pathways while cartilaginous fish are the first species in which the classical pathway appears following the emergence of immunoglobulins. The rest of the poikilothermic species, ranging from teleosts to reptilians, appear to contain a well-developed complement system resembling that of the homeothermic vertebrates. It seems that most of the complement components have appeared after the duplication of primordial genes encoding C3/C4/C5, fB/C2, C1s/C1r/MASP-1/MASP-2, and C6/C7/C8/C9 molecules, in a process that led to the formation of distinct activation pathways. However, unlike homeotherms, several species of poikilotherms (e.g. trout) have recently been shown to possess multiple forms of complement components (C3, factor B) that are structurally and functionally more diverse than those of higher vertebrates. We hypothesize that this remarkable diversity has allowed these animals to expand their innate capacity for immune recognition and response. Recent studies have also indicated the possible presence of complement receptors in protochordates and lower vertebrates. In conclusion, there is considerable evidence suggesting that the complement system is present in the entire lineage of deuterostomes, and regulatory complement components have been identified in all species beyond the protochordates, indicating that the mechanisms of complement activation and regulation have developed in parallel.
Animals↗
The duration of human ocular Chlamydia trachomatis infection is age dependent.
We studied the relationship between age and prevalence, duration and incidence of clinical and laboratory evidence of ocular Chlamydia trachomatis infection in a cohort of Gambian subjects examined bi-weekly for 6 months. The duration of disease and infection, estimated by stratified survival analysis, proportional hazards regression and Weibull modelling, was markedly age-dependent. The estimated median duration of disease was 13.2 weeks in 0-4-year-old subjects and 1.7 weeks in those age 15 and over. Adjustment for multiple infections, and for missing observations did not alter this trend. The cumulative incidence rate of disease was reduced threefold with age. More rapid disease resolution is the main source of reduction in prevalence of active trachoma and ocular C. trachomatis infection with age; disease incidence was reduced to a lesser extent. This age-dependent resolution may be effected by adaptive cellular immune mechanisms. Mechanisms responsible for natural immunity should receive appropriate emphasis in vaccine design.
Adolescent↗