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At least 289 records · Page 16Linked to original sources
PubMed1997

Regulatory role of exogenous IL-10 in the development of immune response versus Cryptococcus neoformans.

The most important event involved in host defence against Cryptococcus neoformans is the development of an adequate cell-mediated immune response. IL-10, abundantly produced during AIDS progression, could be a negative factor that affects the T cell response through its own immunosuppressive action on antigen-presenting cells. To determine whether this cytokine affects the course of immune response against C. neoformans, we added exogenous IL-10 to cultured Cryptococcus-laden monocytes plus T lymphocytes. The data from this study confirmed the down-regulatory effect of exogenous IL-10 on monocytes and expanded the known inhibitory role to include an increase of the deleterious effect due to capsular material of C. neoformans on (i) lymphoproliferation, (ii) down-regulation of MHC class II molecules, (iii) inhibition of IL-2 mRNA expression and protein secretion by T lymphocytes. These results indicate that the presence of IL-10 in AIDS patients, due to the progression of disease, could represent a pivotal problem contributing to augment the pathogenic effect of C. neoformans.

Antibodies, Fungal↗
PubMed2004

Effect of dietary ribonucleotides on infant immune status. Part 2: Immune cell development.

The objective of this study was to determine whether dietary ribonucleotides alter immune cell phenotypes or function in the first year of life. Newborn term infants in a double-blind, 12-mo, multicenter trial were randomized to cow milk formula groups with (FN, n = 138) or without (F, n = 147) 72 mg/L supplemental ribonucleotides. A nonrandomized HMF cohort (n = 192) was concurrently enrolled. Eighty-eight immune blood cell types were characterized by flow cytometry. Data were analyzed by multivariate ANOVA (MANOVA), ANOVA, and repeated measures analysis (RMA), with adjustments made for multiple comparisons. Ribonucleotide feeding changed subpopulations of T and natural killer (NK) cells. FN had higher numbers and percentages of memory/effector (M/E) cytotoxic/suppressor (CD45R0(+)CD8(+), RMA) T, Fas(+) M/E (CD45R0(+)CD95(+)CD3(+), 6 mo) T, and CD56(+)CD16(-) NK cells (CD56(+)CD16(-)CD3(-)CD8(-), 12 mo), and higher percentages of M/E helper (CD45R0(+)CD4(+), RMA) T, Tc1 (IFN gamma(+)CD4(-)CD3(+), RMA), total interferon (IFN)gamma T (IFN gamma(+)CD4(+/-)CD3(+), RMA), Th2 (IL-4(+)CD4(+)CD3(+), 7 mo), and CD57(+) NK-T cells (CD57(+)CD56(-)CD3(+), 6 mo, 7 mo) compared with F. Percentages of naive helper T (CD45RA(+)CD4(+), 12 mo) and numbers and percentages of CD56(+) NK-T cells (CD56(+)CD16(-)CD3(+)CD8(-), 2 mo, 6 mo) were lower in FN than F. Percentages of M/E cytotoxic/suppressor, Th2, and CD56(+)CD16(-) NK cells in FN were significantly higher than F but were not different from HMF, whereas F was significantly lower than HMF. Ribonucleotide supplementation of infant formula supported increased T-cell maturation and affected immunoregulatory NK cell subsets. These FN-associated immune cell profiles either did not differ from those infants fed HMF or tended to be more like those fed HMF than those fed F.

Analysis of Variance↗
PubMed1981

The response of mice immune to Schistosoma mansoni to a challenge infection which bypasses the skin: evidence for two mechanisms of immunity.

Mice which had developed immunity to reinfection with Schistosoma mansoni following exposure to 20 cercariae and mice which had been immunized against S. mansoni by exposure to 400 highly irradiated (20 krad) cercariae, were tested for their ability to resist a percutaneous cercarial challenge and an intravenous challenge with 5-day-old lung-stage schistosomula derived from the same cercariae. Although both types of immune mice showed a marked resistance to a cercarial challenge, only the infected mice showed a comparable immunity to an intravenous challenge with lung schistosomula. These results confirm earlier studies which suggest that the major attrition of a cercarial challenge in infected mice occurs at the post-lung stage, whilst the attrition of a challenge infection in mice immunized with highly irradiated cercariae takes place in the skin. They provide further evidence for two separate mechanisms of immunity against S. mansoni in mice.

Animals↗
PubMed1995

T cell reconstitution after bone marrow transplantation into adult patients does not resemble T cell development in early life.

Immune reconstitution after marrow transplantation has some characteristics of immune development in early life. Here we provide phenotypic data suggesting this may not be true for T cells (particularly CD4+ T cells) in the case of marrow transplantation into adults. T cells from 35 adult patients at 1 year after transplant, 14 normal neonates and 22 normal adults were studied by 3-color flow cytometry. Marked disparity between the phenotype of neonatal vs post-transplant T cells was found. Of the total CD4+ T cells, the neonates had supranormal percentages of CD45RAhigh, L-selectin+, CD29low/-, CD11alow/- and CD28+ cells whereas most patients at 1 year after transplant had subnormal percentages of these CD4+ T cell subpopulations. (sub/supra-normal denotes below/above normal adult values). Absolute blood counts of naive (CD45RAhigh, L-selectin+, CD29low/- and CD11alow/-) CD4+ T cells correlated inversely with patient age. Neonates had also supranormal percentages of CD45RAhigh, L-selectin+, CD29low/-, CD11alow/- and CD28+ CD8+ T cells whereas the patients (particularly those with chronic GVHD) tended to have subnormal percentages of these CD8+ T cell subpopulations. Contrary to the CD4+ T cells, there was no correlation between the absolute counts of CD45RAhigh, L-selectin+, CD29low/- or CD11alow/- CD8+ T cells and patient age. Whereas the vast majority of neonatal T cells were CD38high, most patient and normal adult T cells were CD38- or CD38intermediate (both CD4+ and CD8+ T cells). We conclude that, in contrast to early life, the production of naive CD4+ T cells is deficient in adult (and particularly elderly) transplant recipients.

Adolescent↗
PubMed1969

Human immunity to the meningococcus. II. Development of natural immunity.

Results of the present study suggest that natural immunity to meningococcal disease is initiated, reinforced, and broadened by intermittent carriage of different strains of meningococci throughout life. In young adults, carriage of meningococci in the nasopharynx is an efficient process of immune sensitization. 92% of carriers of serogroup B, C, or Bo meningococci were found to develop increased titers of serum bactericidal activity to their own meningococcal isolate, and 87% developed bactericidal activity to heterologous strains of pathogenic meningococci. The rise in bactericidal titer occurred within 2 wk of onset of the carrier state, and was accompanied by an increase in titer of specific IgG, IgM, and IgA antibodies to meningococci. In early childhood, when few children have antibodies to pathogenic meningococci, active immunization seems to occur as a result of carriage of atypical, nonpathogenic strains. Immunity to systemic meningococcal infection among infants in the neonatal period is associated with the passive transfer of IgG antibodies from mother to fetus. The antigenic determinants which initiate the immune response to meningococci include the group-specific C polysaccharide, cross-reactive antigens, and type-specific antigens.

Adolescent↗
PubMed2006

Role of tumor necrosis factor alpha in development of immunity against Cryptosporidium parvum infection.

Tumor necrosis factor (TNF-alpha) significantly reduced Cryptosporidium parvum development in a murine enterocyte cell line, and a key mechanism of action appeared to be inhibition of parasite invasion. However, TNF-alpha-deficient mice controlled infection as effectively as wild-type mice. This suggests that TNF-alpha might have only a redundant role for establishing immunity against C. parvum.

Animals↗
PubMed1984

Effects of triiodothyronine treatments on body and organ growth and the development of immune function in dwarf chickens.

The effects of triiodothyronine (T3) treatments on general body growth, long bone growth, primary lymphoid organ development, antibody production, and serum growth hormone (GH) and thyroid hormone levels were examined in two dwarf strains (sex-linked dwarf--SLD, and autosomal dwarf--ADW) and in a normal-growing control strain (K) of White Leghorn chickens. One-day-old male chicks from each of these strains were assigned to either an untreated control group or to one of the groups receiving a T3 supplement ranging from 0.01 to 1.0 ppm. General body growth and long bone growth were significantly (P less than 0.05) stimulated only within the SLD strain by the intermediate T3 dosages. The 1.0-ppm T3 dosage level resulted in depressed body weights within both the K and ADW strains but produced no significant changes within the SLD strain. Thymic growth was significantly stimulated due to treatments of 0.1 ppm T3 in the SLD strain (P less than 0.05) and 1.0 ppm T3 in both the SLD and ADW strains (P less than 0.001 and P less than 0.05, respectively). Bursal growth was significantly depressed (P less than 0.05) at all T3 dosage levels within the SLD strain while 0.01 and 0.1-ppm T3 treatments resulted in significant bursal growth stimulation in the K and ADW strains, respectively. Concomitant with the depressed bursal growth, antibody production was significantly depressed (P less than 0.05) within the SLD strain at the 1.0-ppm T3 dosage level. Antibody production was not significantly affected by any of the T3 treatments within the control K or ADW strains. Serum T3 levels were significantly increased in all strains by the T3 supplementation but thyroxine (T4) serum levels were affected only within the SLD strain. The 0.01-ppm T3 treatment resulted in a significant increase (P less than 0.05) in serum T4 levels within this strain and treatment group. The only increase (P less than 0.05) in GH levels due to T3 treatments occurred within the same SLD treatment group. The higher T3 treatments resulted in serum GH levels being severely depressed (P less than 0.01) in all strains.

Animals↗
PubMed1976

Influence of cell-free tumour-associated antigen preparations on the development of immunity to chemically induced rat tumours.

Inbred rats were treated with extranuclear tumour membrane fractions or 3 M KCl-solubilized extracts of two antigenically distinct 3-methylcholanthrene-induced sarcomas, Mc7 and Mc57. The rats developed tumour-specific humoral antibody responses, but were not immune to tumour challenge. Moreover, they were unresponsive to subsequent immunization with irradiated tumour grafts, this effect being immunologically specific for the tumour from which the cell-free extracts was derived. In vitro studies revealed a depressed state of cell-mediated tumour immunity in animals inoculated with cell-free tumour extracts, and this was associated with the presence of serum inhibitory factors and suppressor lymphoid cells which abrogated the cytotoxic effect of sensitized lymphoid cells in vitro. It is postulated that the development of an inappropriate immune response due to the effect of tumour antigen during the induction phase of tumour immunity may be relevant to the immunobiology of tumour-bearing hosts.

Animals↗
PubMed2005

Gene-environment interaction effects on the development of immune responses in the 1st year of life.

Asthma is a common disease that results from both genetic and environmental risk factors. Children attending day care in the 1st year of life have lower risks for developing asthma, although the mechanism for this "day care" effect is largely unknown. We investigated the interactions between day care exposure in the 1st 6 mo of life and genotypes for 72 polymorphisms at 45 candidate loci and their effects on cytokine response profiles and on the development of atopic phenotypes in the 1st year of life in the Childhood Onset of Asthma (COAST) cohort of children. Six interactions (at four polymorphisms in three loci) with "day care" that had an effect on early-life immune phenotypes were significant at P<.001. The estimated false-discovery rate was 33%, indicating that an estimated four P values correspond to true associations. Moreover, the "day care" effect at some loci was accounted for by the increased number of viral infections among COAST children attending day care, whereas interactions at other loci were independent of the number of viral infections, indicating the presence of additional risk factors associated with day care environment. This study identified significant gene-environment interactions influencing the early patterning of the immune system and the subsequent development of asthma and highlights the importance of considering environmental risk factors in genetic analyses.

Asthma↗
PubMed1994

Human immunization in developing countries: practical and theoretical problems and prospects.

While measles, pertussis and tetanus were responsible during the early 1990s for nearly two million deaths in developing countries, no deaths were attributable to them in industrialized countries. More than 96% of global deaths by communicable diseases were also from developing countries. Respiratory infections ranked first in communicable morbidity at all ages. Even though vaccines of bacterial or viral origin or a prophylactic for passive immunization are produced in 24, 16 and 15 developing countries, respectively, none of the developing countries manufactures a plasma-derived prophylactic or biological response modifier. Nearly every country relies on import of one or more vaccines. The suboptimal performance of otherwise meritorious products has been due to faulty vaccine administration practices. Expanding populations, poverty and lack of education, cold-chain defects, and inadequate facilities for transport of vaccines to target populations in remote areas have been responsible for the poor performance of vaccines in the community. Mounting foreign debts and budgetary strains resulting from the care and prevention of AIDS/HIV have considerably strained national and international efforts to offer routine vaccinations in childhood and pregnancy. This dismal situation could be tackled through research to obtain environmentally stable products for prophylactic use and monoclonal antibody formulations for passive immunization, and through international financial and technical support. All countries should exercise some technical control of the quality of imported and indigenous vaccines during their use for curative or prophylactic purposes. The involvement of private clinicians in immunizations would strengthen national efforts for control of communicable diseases including AIDS, but this is not enough if the local factors cited above are not improved.

Bacterial Vaccines↗
PubMed1994

Anti-IL-4 monoclonal antibody and IFN-gamma administration retards development of immune dysfunction and cytokine dysregulation during murine AIDS.

This study was designed to determine if administration of anti-interleukin-4 (IL-4) monoclonal antibody (mAb), interferon-gamma (IFN-gamma) and their combination after LP-BM5 retrovirus infection of female C57BL/6 mice would prevent retrovirus-induction of immunosuppression and cytokine dysregulation. Splenic natural killer (NK) cell activity, T- and B-cell proliferation, and T-helper type 1 (Th1) and Th2 cytokine (IL-2, IFN-gamma, IL-5 and IL-10) and monokine [IL-6 and tumour necrosis factor-alpha (TNF-alpha)] secretions were monitored, as they are usually altered dramatically after murine retrovirus infection. Administration of IFN-gamma and anti-IL-4 significantly prevented retrovirus-induced suppression of splenic NK cell activity, and splenic T- and B-cell proliferation. They also significantly slowed retrovirus-induced elevation of Th2 cytokine (IL-5 and IL-10) release and monokine (IL-6 and TNF-alpha) secretion by splenocytes. They prevented the loss of Th1 cytokine (IL-2 and IFN-gamma) release by splenocytes, and alleviated splenomegaly and hypergammaglobulinemia, precursor signs of development of acquired immune deficiency syndrome (AIDS). These findings could provide insight into the roles of immunomodulator in AIDS treatment as well as the mechanisms by which retrovirus infection induces cytokine dysregulation, facilitating immunodeficiencies in AIDS.

Animals↗
PubMed1991

Supplemental use of liquid amprolium in skip-a-day feeding of replacement pullets.

The addition of liquid amprolium to the drinking water on days when medicated (amprolium) ration was not fed in a restricted feeding (skip-a-day) program improved protection against a primary exposure to Eimeria acervulina and Eimeria tenella, yet still allowed for the development of protective immunity to subsequent challenge. With E. tenella, the best protection, as measured by reduction of lesion score, was provided by amprolium given in the drinking water on alternate days to feed medication when compared with the use of amprolium only in the feed or liquid amprolium at less frequent intervals (every second or third nonfeeding day). With Eimeria maxima, amprolium in the feed did not significantly lower lesion score compared with the score in unmedicated pullets; however, the further addition of amprolium to the drinking water did. When pullets were reared in floor pens previously seeded with coccidia, amprolium medication in the feed alone reduced the E. tenella-induced mortality rate from 28 to 8%. The addition of amprolium in the drinking water on nonfeeding days eliminated all deaths. Floor-reared pullets were caged after 3 wk and challenged 1 wk later with the same species of coccidial oocysts used to immunize on the floor. Coccidial lesion scores following challenge were eliminated or markedly lower than in pen-reared (unimmunized) pullets similarly challenged. This indicated that protective immunity developed despite the use of amprolium in the drinking water.

Amprolium↗
PubMed2001

The developing human immune system: T-cell receptor repertoire of children and young adults shows a wide discrepancy in the frequency of persistent oligoclonal T-cell expansions.

While the T-cell receptor (TCR) repertoire of the newborn is highly diverse, a gradual alteration in diversity of the expressed TCR repertoire, in particular the oligoclonality of CD8+ T cells, occurs with increasing age. The timing of the initiation of this process is unknown. These changes are associated with an accumulation of T-cell expansions, thought to be in response to chronic antigen stimulation, frequently by persistent viruses such as Epstein-Barr virus (EBV) and cytomegalovirus (CMV). Using reverse transcription-polymerase chain reaction heteroduplex analysis we have characterized the TCR expression of CD4 and CD8 cells from healthy young children and adults in order to delineate the age range at which these oligoclonal populations appear. We demonstrate that considerable oligoclonality can occur, even in healthy young children, and also that these expanded clonotypes persist. These are shown by heteroduplex to be exclusively within the CD28- subpopulation. The presence of such oligoclonal expansions correlates closely with the percentage of CD8+ cells that have the CD28- phenotype. However, we also show that control of chronic infection with EBV or CMV may coexist with a highly diverse, polyclonal TCR repertoire well into adulthood. These studies suggest that many factors affect the overall regulation of clone size in response to chronic antigens during the development of the immune system.

Adolescent↗
PubMed1995

Transgenic animals as models for human disease.

Since its first description in 1981 (1), transgenic technology has greatly influenced the focus and direction pace of biomedical research. Introduction of foreign DNA into the genome of animals by microinjection into fertilized oocytes is now used in almost every field of research spanning from oncology, immunology and neurology to cardiovascular medicine. The ability to integrate genes in the germline and their successful expression in the host provides an opportunity to study the role of a certain gene in the initiation and propagation of disease. Transgenic methodology serves as the link between molecular biology, introducing in vitro a defined genetic modification and whole animal physiology, with the resulting in vivo alteration of body function. This potential has been exploited to study the pathophysiological role of human genes. Transgenic animals have been used to study aspects of tumor development, immune regulation, cardiovascular development and atherosclerosis. These studies have provided new insights into the genetic origin of certain diseases and have improved our understanding of pathological processes on the cellular level. As a future goal, these studies may also serve the development of new diagnostic tools or novel therapeutic strategies such as gene therapy.

Animals↗
PubMedDate not supplied

Human immunodeficiency virus type 1 infection in patients with severe falciparum malaria in urban India.

BACKGROUND: CD4+ T cells restrict parasitaemia during the first attack of falciparum malaria; humoral immunity, develops weeks later and protects against reinfection. HIV infection may affect severity of falciparum malaria and development of protective immunity. AIMS: To study the prevalence of HIV infection in Indian patients with severe falciparum malaria and its effect on severity of illness and recurrences of and mortality related to malarial infection. PATIENTS: Consecutive patients with severe falciparum malaria and voluntary blood donors. SETTING AND DESIGN: Prospective cohort study in a university hospital in Mumbai. RESULTS: Five (11.6%) of 43 patients and 521 (1.8%) of 28749 blood donors had HIV infection (OR 7.1, 95% CI = 2.8 to 18.2, p=0.001). Clinical features, APACHE II score, number of organs affected, parasite index and mortality in patients with and without HIV infection were comparable. CD4+ counts were < 500 cells/ microl in 2 patients and normal in 3. Opportunistic infections including pulmonary tuberculosis in one patient (CD4+ counts > 500 cells/ microl), and oral candidiasis in two (CD4+ counts 275 and 250 cells/ microl) were noted. One patient developed fatal Pneumocystis carinii pneumonia two weeks after recovering from malaria. P. falciparum infection recurred in 2 of the 4 HIV infected survivors and in none of 31 survivors without HIV infection (RR 38.8, 95% CI 2.2 to 671, p=0.01). CONCLUSIONS: HIV infection is associated with increased risk of severe malaria even with normal CD4+ counts; severity of disease and mortality are not increased. However, prior HIV infection impairs protective immune response to Plasmodium falciparum in residents of hypoendemic areas.

Adult↗
PubMed1995

Theileriosis: progress towards vaccine development through understanding immune responses to the parasite.

Studies of the immune responses of cattle to Theileria parva have provided evidence that immunity to the parasite can operate at two levels, namely the sporozoite and the schizont-infected lymphoblast. Antibodies that neutralize the infectivity of sporozoites have been detected in the serum of hyperimmunized cattle, and a recombinant sporozoite surface antigen has been shown to induce neutralizing antibodies and protection against experimental challenge. However, the immunity that develops following primary infection with T. parva is accompanied by only low levels of antibodies to sporozoites; there is overwhelming evidence that under these circumstances protection is mediated by T cell responses against infected lymphoblasts. Potent class I MHC-restricted cytotoxic T lymphocyte (CTL) responses are detected in animals recovering from infection and treatment or challenge infections. Two recent findings have provided direct evidence for the importance of these responses in immunity. First, the strain specificity of CTL in cattle immunized with one stock of the parasite was found to correlate with the subsequent susceptibility of individual animals to challenge with a heterologous cloned parasite population (in these circumstances some animals are protected whereas others are susceptible to the heterologous challenge). Second, the adoptive transfer of lymphocytes highly enriched for CD8+ T cells, from immune to naive identical twin calves, was found to protect against experimental challenge. The CTL response in individual animals appears to be directed towards a limited number of antigenic epitopes. The antigenic specificity is determined in part by class I MHC phenotype although there is evidence that other phenomena such as antigenic competition are also involved. Current efforts are directed towards identification of the parasite antigens recognized by CTL with the eventual aim of exploring their potential for vaccination.

Animals↗
PubMed2006

Lectin anchored stabilized biodegradable nanoparticles for oral immunization 1. Development and in vitro evaluation.

The investigation comprises development of a stable and targeted formulation of HBsAg for the oral immunization against Hepatitis B. PLGA nanoparticles bearing HBsAg was prepared by double emulsion method. The antigen was protected from organic/aqueous interface by using protein stabilizer, trehalose. The acidic environment generated within PLGA nanoparticles was neutralized by co-encapsulation of a basic additive, Mg(OH)(2) which provides an additional stabilization to the antigen especially against acid induced antigen inactivation. Furthermore, lectin from Arachis hypogaea (PNA) was anchored on to the surface of the HBsAg loaded nanoparticles in order to enhance their affinity towards the antigen presenting cells of the Peyer's patches. The developed system was characterized for shape, size and loading efficiency. The antigen integrity was assessed by using SDS-PAGE followed by isoelectric focusing analysis. Bovine submaxillary mucin (BSM) was used as a biological model for in vitro ligand affinity determination and activity studies. The lectin anchored nanoparticles exhibited 52.18+/-4.73% loading while ligand density was estimated to be of 17.90+/-1.14 microg/mg. The results suggest that HBsAg can be successfully stabilized by co-encapsulation of an appropriate protein stabilizer, i.e. trehalose and a basic additive, Mg(OH)(2). The ligand-coupled nanoparticles demonstrated approximately four folds increase in degree interaction with the BSM as compared to plain nanoparticles. Additionally, the nanoparticles maintained their intrinsic sugar specificity as associated due to lectin (PNA).

Administration, Oral↗