Decline In Immunocompetence Research Articles

Infection with a non-lethal fungal parasite is associated with increased immune investment in the ant Myrmica scabrinodis

Social insects, such as ants, are preferred host organisms of pathogens and parasites because colonies are densely populated, and the number of potential hosts is high in the same place and time. Within a colony, individuals are exposed differentially to risks according to their function and age. Thus, older individuals forage and are therefore the most exposed to infection, predation, or physical stress, while young workers mostly stay inside the sheltered nest being less exposed. Immune investment is considered to be dependent on an individual’s age and pathogen pressure. Long-term exposure to a parasite could affect the immune activity of individuals in an intriguing way that interferes with the age-dependent decline in immunocompetence. However, there are only few cases in which such interferences can be studied. The myrmecopathogenic fungus Rickia wasmannii, which infects entire colonies without killing the workers, is a suitable candidate for such studies. We investigated the general immunocompetence of Myrmica scabrinodis ant workers associated with non-lethal fungal infection by measuring the levels of active phenoloxidase (PO) and total PO (PPO) (reflecting the amount of both active and inactive forms of the enzyme) in two age classes. The level of PO proved to be higher in infected workers than in uninfected ones, while the level of PPO increased with age but was not affected by infection. Overall, these results indicate that a long-term infection could go hand in hand with increased immune activity of ant workers, conferring them higher level of protection.

Neutrophil-to-Lymphocyte Ratio As a Predictor of All-Cause Mortality in the General Population and Patients with Myeloproliferative Neoplasms

Background: Across the human lifespan, an age-related decline in immunocompetence and a concurrent increase in chronic inflammation are evident. The Philadelphia-negative myeloproliferative neoplasms (MPNs) represent a heterogeneous group of acquired hematopoietic stem cell diseases where chronic inflammation is essential for both the clonal evolution and development of comorbidities prior to and after diagnosis. Neutrophilic heterogeneity is well described where neutrophils have the capability to inhibit T-lymphocytes and natural killer cells, potentially implying reduced immune competence, which may enhance the clonal progression and evolution of the malignant clone. Thus, the neutrophil-to-lymphocyte ratio (NLR) is a simple biomarker index that both encapsulates chronic inflammation and reduced immune competence. Increased NLR is associated with several inflammatory-mediated diseases, including MPNs. Aims: We investigated if increased NLR is associated with higher all-cause mortality in both the general population and in patients with myeloproliferative neoplasms in a Danish Cohort with 18 years of follow-up. Methods: Blood cell count measurements were used from The Copenhagen Primary Care Laboratory Database (CopLab), and three hospital-derived Laboratory Information Management Systems from Roskilde, Copenhagen, and the Northern part of Jutland. First, occurring neutrophil and lymphocyte counts were used. Inclusion criteria were an age ≥20 years, hsCRP or CRP <10mg/L. Individuals with inpatient stay or emergency room admissions ±15 days from the sample date were excluded using the Danish National Patient Registry (DNPR), thus allowing only outpatient hospital and general practitioner visits. On included individuals (N=272,933), comorbidities were retrospectively assessed across 19 major disease categories to calculate the Charlson Comorbidity Index score (CCI) using ICD8 and ICD10 codes from DNPR. The sample date for blood count measurements was used as the index date for CCI calculation. MPNs were defined by ICD8 (ET: 28729, PV: 20899, MF: 20900) and ICD10 (ET: DD474 / DD752, PV: DD459, MF: DD474 ). MPN diagnosis after sample date and during follow-up was termed pre-MPN. The CCI score was defined as having 0, 1-2, or >2 comorbidities. NLR was calculated and categorized as NLR <1.5, NLR ≥1.5 - 2, NLR ≥2 - 3, NLR ≥3 - 4, and NLR ≥4. All-cause mortality was ascertained from the National Danish Causes of Death Registry. We used proportional hazard Cox-regression analysis to estimate the hazard ratio (HR) with a 95% confidence interval (95%CI) to investigate all-cause mortality in the general population, MPN patients, and the impact of CCI-score. The analyses were adjusted for age, gender, population, CCI, or NLR. Results: Among 272,933 individuals, 85 had MPN prior to the sample date, whereas 469 developed MPNs during the observation time. Compared to non-MPNs, preMPNs and MPNs had more accumulated comorbidities in both the 1-2 CCI score (17.4% vs. 26.4% vs. 37.7%) and >2 CCI score (4.1% vs. 8.5% vs. 23.5%),P < 2.2x10-16, see figure 1A. For the NLR strata, a stepwise increase in CCI scores was also evident in the 1-2 and >2 CCI scores, P < 2.2x10-16, see figure 1A. During follow-up with 42,831 events, a stepwise increase in all-cause mortality was observed across the population (see figure 1B). Compared to NLR <1.5 (reference group), NLR 1.5-2 had a HR(95%CI) of 1.05 (1.02 - 1.09), P=0.003, NLR 2-3 had a HR(95%CI) of 1.23 (1.20 - 1.27), P <2x10-16, NLR 3-4 had a HR(95%CI) of 1.48 (1.43- 1.53), P<2x10-16 whereas the highest HR(95%CI) was observed among individuals with NLR ≥4 of 1.83 (1.77-1.89),P <2x10-16. We also investigated the impact of CCI and MPNs on all-cause mortality. Compared to No MPNs & No CCI (reference group), No MPN with 1-2 or >2 CCI had an HR(95%CI) of 1.90 (1.85 - 1.93), P <2x10-16 and 3.25 (3.16 - 3.35), P<2x10-16, respectively. In contrast, individuals with MPNs & 0 CCI, 1-2 CCI or >2 CCI had a HR(95%CI) of 2.20 (1.39 - 3.50), P=0.0008, 3.62 (2.25 - 2.58), P=1.17x10-7, and 8.15 (4.90 - 13.52), P=4.78x10-16, respectively. We observed similar results of NLR and MPNs on all-cause mortality. Conclusion: In a general population study, we observed a stepwise increase in mortality among individuals with higher NLR compared to NLR<1.5. Individuals with higher NLR, preMPN, and MPNs had more comorbidities than those with lower NLR and No MPNs measured by the CCI score. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

P0433AGE-RELATED DIFFERENCES IN THE SPECTRUM OF BIOPSY-PROVEN GLOMERULONEPHRITIS

Abstract Background and Aims The proportion of geriatric population is increasing globally and age-related changes, as kidney ageing and decline in immunocompetence, might interfere with frequency of various glomerulopathies (GP). Thus, it is conceivable that the spectrum of biopsy-proven GP varies across different age categories. Accordingly, we aimed to describe age-related variation in clinical presentation and the in prevalence of GP diagnosed by kidney biopsy (KB) in adults. Method This retrospective study enrolled 1254 subjects selected from the KB database of a large tertiary academic Nephrology center (which provides specialized care for the south-eastern part of our country), over a ten-year span (01.01.2008-31.12.2017). Inclusion criteria were age &amp;gt;18 years, native kidney biopsy, availability of data from light, immunofluorescence, and electron microscopy, and a histologic diagnosis of GP. Repeated biopsies and inadequate tissue samples were excluded. Demographic (age, gender), clinical and laboratory data at the time of biopsy were extracted from medical records for all the selected subjects. To investigate the possible influence of age on the spectrum of biopsy-proven GP, the cohort was divided into 4 categories: young adults (18 to 30 years, n=156), adults (31 to 64 years, n=868), elderly (65 to 74 years, n=176) and very elderly (≥75 years, n=54), and the collected data were compared by non-parametric methods (Mann-Whitney, Chi2 and Fisher exact tests). Results The nephrotic syndrome was the most common presentation form in all age groups but had a higher prevalence in very elderly (62%) and elderly (55%) as compared to adults (37%, p=0.01) and young adults (41%, p&amp;lt;0.001). In the groups below age of 65, the chronic nephritic syndrome was the second most common indication for KB (31% and 28%, respectively), followed by chronic renal failure in adults (13%) and acute nephritic syndrome in young adults (10%). Lupus nephritis (LN) and IgA nephropathy (IgAN) were the most commonly diagnosed GP in young adults (22% each), followed by minimal change disease (MCD, 14%), membranous nephropathy (MN, 8%), focal and segmental glomerulosclerosis (FSGS, 8%), and thin basement membrane disease (6%). In adults, the most common GP were: IgAN (23%), MN (15%), diabetic nephropathy (DN, 11%) and MCD (10 %). Conversely, in both the elderly and the very elderly, the most common biopsy-proven GP was MN (26% each). Elderly had renal amyloidosis as the second most prevalent histological diagnosis (17%), followed by DN (11%), and by IgAN and MCD (≈10% each). Crescentic glomerulonephritis (CGN) occurred in 7.5% of the elderly, but it was the second pathology (17%) in subjects aged 75+ years, followed by MCD (15%) and DN (13%). IgAN and amyloidosis were identified in about 5% of this group. It appears that the prevalence of both clinical presentation and histologically diagnosed GP showed some similarities between the first two and, respectively, last two age categories. Conclusion Biopsy-proven GP have different frequencies depending on the patient’s age, with some pathologies predominantly found at older ages (such as membranous nephropathy, amyloidosis and crescentic GN) or, on the contrary, typical for young adults (lupus nephritis and IgAN). These differences account for the distinct clinical presentations at the time of KB.

Age-related profiling of DNA methylation in CD8+ T cells reveals changes in immune response and transcriptional regulator genes.

Human ageing affects the immune system resulting in an overall decline in immunocompetence. Although all immune cells are affected during aging, the functional capacity of T cells is most influenced and is linked to decreased responsiveness to infections and impaired differentiation. We studied age-related changes in DNA methylation and gene expression in CD4+ and CD8+ T cells from younger and older individuals. We observed marked difference between T cell subsets, with increased number of methylation changes and higher methylome variation in CD8+ T cells with age. The majority of age-related hypermethylated sites were located at CpG islands of silent genes and enriched for repressive histone marks. Specifically, in CD8+ T cell subset we identified strong inverse correlation between methylation and expression levels in genes associated with T cell mediated immune response (LGALS1, IFNG, CCL5, GZMH, CCR7, CD27 and CD248) and differentiation (SATB1, TCF7, BCL11B and RUNX3). Our results thus suggest the link between age-related epigenetic changes and impaired T cell function.

高温刺激对蟾蜍免疫活性和能量消耗的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 高温刺激对蟾蜍免疫活性和能量消耗的影响 DOI: 10.5846/stxb201306161715 作者: 作者单位: 浙江师范大学生态研究所,浙江师范大学生态研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(30800129, 31270457) The effects of hyperthermia on immunocompetence and energy consumption in Bufo bufo gargarizans Author: Affiliation: Institute of Ecology,Zhejiang Normal University,Institute of Ecology,Zhejiang Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:全球气候变化是导致全世界两栖动物种群衰退和灭绝的重要因素之一。为了解无尾两栖类在气候异常导致的极端高温下的生理反应特征和相关适应机制,以雄性中华大蟾蜍(Bufo bufo gargarizan)为对象,研究该物种在高温刺激(环境温度由22 ℃迅速升至32 ℃)0、6、12、24、48 h后的非特异性免疫活性和能量消耗的变化情况。研究结果:与对照组(22 ℃)比较,高温刺激可显著抑制外周血细胞吞噬活性;而脾脏巨噬细胞呼吸爆发在高温刺激下呈现出先增强后减弱的趋势。高温刺激导致血糖含量在第24和48 h显著低于对照组,而对肝糖原含量无显著影响。处理组精巢ATP含量逐渐升高,并于24和48 h显著高于对照组;处理组Na+-K+-ATPase活性随时间呈现出先下降后上升稳定的趋势,但与对照组相比均无显著性差异,;处理组Ca2+-Mg2+-ATPase活性在不同时期与对照组相比均无显著性差异。研究结果说明,高温刺激可显著抑制中华大蟾蜍的非特异性免疫功能,并导致血糖的大量消耗;当面对高温胁迫时,雄性大蟾蜍可能会投入更多的能量来维持性腺的正常发育。 Abstract:Global climate change is a key factor which leads to either a decline or an extinction of amphibian populations worldwide. This paper investigates the effects of high environmental temperatures on non-specific immunity and energy consumption in the male toads (Bufo bufo gargarizans). We found that peripheral blood cell phagocytosis decreases while spleen macrophage respiratory burst activity transiently increases in high-temperature toads (32 ℃) versus control toads (22 ℃). Blood glucose levels decrease in high-temperature toads after 24 h and 48 h exposure versus control toads, while hepatic glycogen content remains unchanged. In addition, the ATP content in the high-temperature toad testis gradually increases and reaches significant levels after 24 h and 48 h exposure versus control toads. Na+-K+-ATPase and Ca2+-Mg2+-ATPase activity show no significant changes. Our results indicate that high environmental temperatures cause a decline in immunocompetence, an increase in glucose consumption, and an accumulation of energy (ATP) within the testis in Bufo bufo gargarizans. 参考文献 相似文献 引证文献

Aging, nutrition and immunity – their relationship and interaction

Demographic shifts worldwide are resulting in ever-increasing numbers of the elderly in both developed and developing countries. With aging come changes in physical and physiological integrity that are accompanied by a gradual decline in immunocompetence, commonly termed 'immunosenescence'. Indeed, there are marked differences between young and old subjects with respect to the proportions of naand memory T cells and less marked differences in B cells and other immune cells. The number and proportion of late-stage memory T and B cells commonly increases, being particularly prominent in the CD8+ cytotoxic T cell pool. The accumulation of late-stage potentially terminally differentiated CD8+CD27−CD28−CD45RA+ cells is often considered a hallmark of immunosenescence. Malnutrition in old age can further add to the severity of this age-associated remodeling of the immune system. Age-associated obesity, in particular, is accompanied by greater chronic inflammation, as reflected in increased plasma concentrations of C-reactive protein (CRP), IL-6, TNF and other factors which may mark compromised immunity. These physiological and immunological changes accompanying aging, markedly affected by nutritional status, are likely to be different in different parts of the globe. Data suggest a gradual decline in both nutritional status and immune functions with aging, but the details of these processes, and potential differences in different societies are unclear. In the following review, we will discuss the hallmarks of age-associated immune system changes and consider how these might be affected by nutritional status.

The Role of Epigenetics in Aging and Autoimmunity

The decline in immunocompetence with age is accompanied by the increase in the incidence of autoimmune diseases. Aging of the immune system, or immunosenescence, is characterized by a decline of both T and B cell function, and paradoxically the presence of low-grade chronic inflammation. There is growing evidence that epigenetics, the study of inherited changes in gene expression that are not encoded by the DNA sequence itself, changes with aging. Interestingly, emerging evidence suggests a key role for epigenetics in human pathologies, including inflammatory and neoplastic disorders. Here, we will review the potential mechanisms that contribute to the increase in autoimmune responses in aging. In particular, we will discuss how epigenetic alterations, especially DNA methylation and histone acetylation, are accumulated during aging and how these events contribute to autoimmunity risk.

Ageing part 3: the digestive, endocrine, genitourinary and immune systems

This third and final article in the series looks at how the gastrointestinal, endocrine, immune and genitourinary systems are affected by ageing. Ageing is a normal process that is accompanied by pathophysiological changes. Gastrointestinal problems experienced by the older person are common; age-related changes associated with some of these problems are caused by muscle weakness. The problems experienced by the older person can impinge on their ability to ingest, digest and excrete waste products. Age-related changes, for example, in those associated with the pancreas can cause a decrease in glucose tolerance and there can be an ineffective release of insulin from the pancreas. When a person ages there is a known general decline in immunocompetence, which could result in the older person developing chronic diseases and disorders. By the time a person reaches the age of 85 years of age renal function has reduced by half, this has implication for the person's health and wellbeing. There is an ageing population and healthcare assistants and assistant practitioners are likely to care for older people in a variety of health and social care settings. Understanding more about the ageing population can help the carer help the older person in a number of ways; the outcome can have a significant effect on an individual's quality of life.

In kittiwakes food availability partially explains the seasonal decline in humoral immunocompetence

Summary 1The immune system plays an important role in fitness, and interindividual variation in immunocompetence is due to several factors including food supply. 2Seasonal variation in food resources may therefore explain why immunocompetence in bird nestlings usually declines throughout the breeding season, with chicks born early in the season receiving more food than chicks born later, and thereby possibly developing a more potent immune system. Although there are studies supporting this hypothesis, none has been experimental. 3We performed an experiment in the kittiwake Rissa tridactyla by manipulating the food supply of pairs that were left to produce a first brood, and of pairs that were induced to produce a late replacement brood. 4If food supply mediates, at least partially, seasonal variations in chick immunocompetence, non-food-supplemented chicks would show a stronger seasonal decline in immunocompetence than food-supplemented chicks. 5Food supplementation improved humoral immunocompetence (the production of immunoglobulins Y), but not T-cell immunocompetence (phytohaemagglutinin, PHA response). T-cell immunocompetence of food-supplemented and non-food-supplemented chicks decreased through the season but to a similar extent, whereas the humoral immunocompetence of non-food-supplemented chicks decreased more strongly than that of food-supplemented chicks. 6Our results suggest that the seasonal decline in humoral immunocompetence can be explained, at least partly, by variations in food supply throughout the breeding season.

Reduced expression of gamma interferon in serum and marked lymphoid depletion induced by Porphyromonas gingivalis increase murine morbidity and mortality due to cytomegalovirus infection.

Porphyromonas gingivalis, a gram-negative anaerobe, is a major etiological agent of severe forms of periodontal disease. Although periodontal disease is considered a localized disease, accumulating evidence indicates that it may lead to a predisposition to a decline in immunocompetence. Human cytomegalovirus (CMV) commonly infects all human populations without producing significant clinical symptoms. Immunocompromised patients usually develop a primary or reactivated CMV infection, which is associated with high rates of morbidity and mortality. The aim of this study was to determine whether P. gingivalis increases animal susceptibility to CMV infection. Mice were inoculated with CMV and infected locally with P. gingivalis 3 days after the virus inoculation. Mortality rates were monitored, and traces of viral DNA and bacterial infection were detected systemically by using real-time PCR. Local and systemic cytokine secretion was measured, and histological sections were used to assess the pathological state of infected organs. P. gingivalis- and CMV-coinfected mice showed dramatically higher mortality rates than mice infected with P. gingivalis or CMV only. Although the organs of coinfected mice exhibited decreased viral titers, distinct necrosis and tissue damage were more evident in the livers and spleens of these mice than in those of mice infected with CMV only. Furthermore, systemic gamma interferon levels were decreased in coinfected mice, and marked lymphoid depletion was observed in their necrotic organs. In parallel control Escherichia coli-CMV coinfection experiments, the mortality and pathological results were the same as those found in mice infected with CMV only. Our results suggest a specific influence of P. gingivalis on the mouse immune response, causing increased susceptibility to CMV infection.

Senescent BALB/c mice are able to develop resistance to Leishmania major infection.

Aging has been associated with a decline in immunocompetence and resistance to infections, partially due to dysregulated NO production by macrophages and deficits in mounting Th2 cell responses. We wondered if these alterations would reverse the immune response in experimental leishmaniasis. Bone-marrow-derived macrophages from 2- and 18-month-old (senescent) C57BL/6 or BALB/c mice showed no marked difference in leishmanicidal functions. In vivo infections of resistant C57BL/6 mice with Leishmania major revealed no difference between senescent and young mice. However, among susceptible BALB/c mice, senescent animals showed less foot-pad swelling than young mice, and 40 to 60% of them even showed healing of ulcers, reduced parasite dissemination, and a Th1 cell response. These changes were associated with a spontaneous release of interleukin-12 (IL-12) by macrophages from aged but not from young mice. Since exogenous microbial stimulation can influence immune responses during aging, we also infected senescent mice who were raised under specific-pathogen-free (SPF) conditions. They showed neither resistance nor a Th1 response, but their macrophages still spontaneously released IL-12. A microbiological analysis showed that conventionally kept mice, but not SPF mice, had experienced infection with murine hepatitis virus (MHV), an infection associated with a Th1-like response. We conclude that for the reversal of the immune response, senescence is the premier requirement but needs to be completed by another mandatory event such as microbial stimulation. One of the age-related, but not environment-related, factors is the spontaneous release of IL-12 by macrophages, while confrontation with MHV presents an environment-related difference, with both having the potential to support a Th1 response.

Reduction of transport stress of ayu by obligated schooling

We investigated stress responses of ayu Plecoglossus altivelis under the hypothesis that overcrowding during transport can be a stressor and the stress predisposes fish to disease by decline in immunocompetence. The extent of stress response was determined under different fish densities. As inferred from the serum concentration of cortisol 1 day after the treatment, the density at more than 23 kg/m3, which was within the range of normal transporting procedures, acutely evoked intense stress responses. To examine a possible way to reduce the stress response of fish under crowding conditions, we compared two fish groups established in water tanks with circulating (whirling) and turbulent currents at the same density. The cortisol levels 1 day after the treatment were 2.5-fold higher in turbulent current than in whirling current. Fish in whirling current formed a school, while those in turbulent current aggregated with each other. Schooling of fish induced by water flow may reduce their stress responses during transport. A transport system with a directional water flow should keep fish in good condition without reducing the number of fish contained.

Changes in lifetime immunocompetence in male and female Gryllus texensis (formerly G. integer): trade-offs between immunity and reproduction

Determining whether males make energetic trade-offs between immunity and reproduction remains difficult, partly because of the complexity of the vertebrate immune system. We studied this question in an insect, which has a simpler immune system. We estimated immunocompetence in the cricket Gryllus texensis by measuring: (1) phenoloxidase (PO) activity, (2) haemocyte number and (3) susceptibility to the bacterium Serratia marcescens. From the last instar to prereproductive adulthood, immunocompetence in males was similar to that observed in females. When males reached the age at which they begin to display reproductive behaviour, PO activity and resistance to S.marcescens declined relative to females and younger males. In females, PO activity increased after the onset of sexual behaviour, relative to female nymphs and prereproductive adult females. Both males and females showed a decline in immunocompetence in old age. Neither weight nor body length correlated with resistance to S.marcescens in either sex. Haemocyte number did not differ between males and females at any age, did not change significantly with the onset of sexual behaviour, and did not correlate with resistance toS.marcescens , suggesting that it does not reflect immunocompetence. These results suggest that immunocompetence decreased in reproductively active males, supporting the hypothesis that males trade off immunity for reproduction. Our results also suggest that immunocompetence may increase in reproductively active females.

Neutrophil function in elderly persons assessed by flow cytometry.

It is well known that the immune response declines with senescence and it is suggested that these changes render an individual susceptible to infection, autoimmune phenomena and cancer. Bacterial and viral infections are a major cause of illness and death amongst aged subjects, and once infection is established, the elderly also have a diminished capacity to prevent its spread (1). The cellular and molecular basis for this age-related decline in immunocompetence are still unknown and, possibly, are related to an alteration in cell transduction mechanisms (2).

Role of endurance exercise in immune senescence.

The immune system undergoes significant changes with advancing age. The increased incidence of malignancy, infectious disease, and autoimmune disorders with age is felt to be linked with this decline of immunocompetence. The aging process does not uniformly affect the immune system, however, and there is a high degree of individual variation. There is growing evidence that the variation in immune function among the elderly is associated at least in part with environmental factors such as nutritional status and physical activity. Although investigation of the relationship between endurance exercise and immune function in elderly subjects has just recently begun, data from the few studies available are intriguing and have potential for widespread public health influence. These data are reviewed in this paper, with directions given for future research.

Cellular automata approach to interacting cellular network models for the dynamics of cell population in an early HIV infection

In order to understand the evolution of cell population in an early HIV infection (AIDS), a network model of interacting cellular elements, such as macrophages, viruses, T4 cells, and T8 cells, is introduced for a cell mediated response. In a simplified discrete representation of binary cells, boolean expressions are used to describe their interactions and concentrations. Two different interaction models are considered and flows of configurations are studied in their configurational phase space. In the mean field (or infinite range interacting network) treatment, one interaction gives two fixed points describing the extreme limits of “immuno-competence” and “immunodeficiency”; in addition, it gives rise to a periodic cycle consisting of an “infected”, a “severely infected”, and a “susceptible” state. The other interaction leads to seven fixed points, two of which are the same as those in the first. The third fixed point represents a “severely infected” state, and the remaining four describe “susceptible” states of varying order. Growth and decay of cellular elements are then studied on a simple cubic lattice where nearest neighbor interactions are treated by inhomogeneous cellular automata using computer simulations. In order to take into account the sporadic growth of virions, an interaction latency parameter B is introduced, and the decline of immunocompetence as a function of B is discussed. A detail study is presented for the crossover between an immunodeficient and an immunocompetent state as a function of the initial concentration of the host cells and latency/dilution.

Enhanced frequency of spontaneous B cell lines from Epstein-Barr virus (EBV) seropositive donors 80 years and older

Based on the well-recognized decline in immunocompetence which develops with advancing age, we have evaluated the effect of age on the frequency of development of spontaneous Epstein-Barr virus (EBV)-infected B cell lines. Blood mononuclear cells were isolated from 38 clinically healthy seropositive donors. The cells were maintained in vitro according to routine culture conditions for lymphocytes. Eight spontaneously EBV-infected B lymphoblastoid cell lines (LCL) were isolated. The LCL developed in 12.5, 14.3, or 6.3% of the samples derived from donors in the three are groups 20–39, 40–59, 60–79, respectively. In contrast, samples from five of seven (71%) donors 80 years and older yielded LCL. Although the reason(s) for the increased frequency of occurrence of spontaneous LCL from the older adults is yet to be explored, the possible role of the virus-specific T lymphocytes as a contributing factor is discussed.

Comparative Pathogenesis of Animal and Human Retrovirus Infections

ABSTRACT The human immunodeficiency virus (HIV) shares some structural and biological features with other lentiviruses such as maedi, visna, and equine infectious anemia viruses. Both the budding p...

Effect of cortisone in delineating thymus cell subsets in advanced age.

The mixed lymphocyte reactivity of thymus cells from normal and cortisone-treated, young and old C57BL/6J mice was evaluated. The results indicated that while in the young mice cortisone treatment caused a 12-fold increase in the reactivity of thymus cells, it had no effect on the response of thymus cells from old mice. The significance of the disappearance of cortisone-resistant mature thymus cells in old mice is discussed regarding the general decline in immunocompetence and the increase of autoimmune manifestations in old age.

Immunodepression as a factor during 3-methylcholanthrene carcinogenesis and subsequent tumour growth in mice.

AbstractCBA/H‐T6 mice received a dose of 3 or 6 mg 3‐methylcholanthrene on day 0 and their spleen cell IgM antibody response to sheep red blood cells was found to be significantly depressed 23 days thereafter. However, at this time, there was no reduction in the ability of spleen cells from these mice to induce a graft‐versus‐host reaction in (A × T6)F1 hybrid animals. On day 68 after 3‐MC injection, six animals had developed tumours while six were still in the latent period. There was no difference in the capacity of spleen cells from these two groups of animals to induce a GvH reaction in F1 hybrids. Three 3‐MC induced sarcomata were serially passaged in isogenic hosts. The growth rates of these tumours increased and the regional lymph nodes and spleens became progressively more hypoplastic in successive hosts. However, there was again no decline in immunocompetence of spleen cells as judged by the induction of a GvH reaction in F1 hybrids. It is therefore suggested that the increase in tumour growth rate reflected a change in the tumour rather than increasing immunodepression of successive hosts.