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Visualizing the viral burden: phenotypic and functional alterations of T cells and APCs during persistent infection.

Persistent viral infections continue to present major public health problems. Failure to achieve virus control confronts the immune system with a chronic viral burden that may involve immune cells themselves and directly compromise the functionality of effector lymphocytes and APCs. In this study we use the lymphocytic choriomeningitis virus system for persistent viral infection of its natural murine host and use analytical techniques for direct ex vivo visualization of virus-infected immune cells. We report that virtually all cells of the immune system can be infected, but the distribution of the viral burden is differentially allocated to lymphocyte and APC subsets of defined phenotypes. Importantly, the profile of immune cell infection found in the blood is broadly representative for the pattern of cellular infection in most organs and is independent of the presence of Abs or complement. By direct comparison of virus-infected and uninfected cell subsets, we demonstrate that lymphocytic choriomeningitis virus-infected T cells show preferential activation, skewed cytokine profiles, and increased apoptosis. In contrast, increased activation of APCs is generalized and independent of the presence of viral Ag. Our data indicate that specific patterns of immune cell infection are associated with distinct forms of immunostimulatory and immunosuppressive alterations that may provide insights into autoimmune processes associated with infectious disease and offer clues for therapeutic interventions aimed at restoration of complete immunity.

Amino Acid Sequence↗

Cytokine profiles using whole-blood assays can discriminate between tuberculosis patients and healthy endemic controls in a BCG-vaccinated population.

Whole-blood assays (WB) provide a simple tool for assessing immune cytokine profiles which may be useful laboratory predictors of early disease, aiding the evaluation of new tuberculosis (TB) vaccines and offering insights into disease pathogenesis. Although BCG does not provide protection against pulmonary disease in TB endemic areas, it does modulate immune responses to mycobacterial antigens. It is important, therefore, to evaluate any new tool in an endemic setting in both BCG vaccinees and patients with tuberculosis. We have assessed the optimal conditions in terms of dose and kinetics of those cytokines which are released early (TNF-alpha, IL6 and TGF-beta, IL10) or (interferon [IFN]-gamma and IL5) in WB cultures stimulated with mitogens and mycobacterial antigens. Responses were studied in parallel in untreated TB patients and endemic control groups. Optimal responses to LPS (predominantly monocyte-derived) occurred on days 1-2, whereas for PHA (predominantly T-cell-derived), they were on days 3-5. Secreted Mycobacterium tuberculosis culture filtrate proteins (CFP) provided a stronger stimulus for monocyte-derived cytokines compared to PPD, but both antigens were comparable for induction of T-cell cytokines. Using unpaired Student's t-tests, pulmonary tuberculosis patients (P.TB; n=11), in response to CFP, showed higher monocyte-derived IL6 (p=0.023) and IL10 (p=0.042) compared to endemic controls (EC; n=13), and significantly suppressed T-cell-derived IFN-gamma (p=0.028) and IL5 (p=0.012) secretion but increased IL10 (p=0.047) on day 5, indicating that CFP is a strong stimulus for IL10 secretion in pulmonary TB patients. Extrapulmonary TB patients (E.TB; n=6) showed no elevation of early monocyte-derived cytokines to either PPD or CFP, but showed a marked suppression of the T-cell-derived cytokines IFN-gamma (PPD, p=0.015; CFP, p=0.05) and IL5 (PPD, p=0.05; CFP, p=0.015). Cytokine analysis in WB cultures is, therefore, able to discriminate between active tuberculosis infection and nondiseased healthy controls.

Adolescent↗

Effects of intensive exercise training on immunity in athletes.

A large number of studies have failed to show whether exercise-induced perturbations in immune function are associated with the incidence of infection. "Sports immunology", examining the interaction of physical, psychological and environmental stress on immunity, is emerging as a sub-discipline of sports medicine. A series of studies by our research team has profiled the immune responses of elite swimmers during training. Serum immunoglobulin and IgG subclass levels were lower in swimmers than controls. Suppression of mucosal immune parameters has been associated with the risk of upper respiratory tract infection. Swimmers with a lower pre-season salivary IgA and/or lower pre-exercise salivary IgA level were more likely to contract an URTI during a 7-month training period. In a shorter 12-week study, infected swimmers had a mean salivary IgM concentration that dropped more sharply after a single training session. Significant declines in natural killer cell count and neutrophil oxidative activity were not associated with URTI. Despite systemic and mucosal immunosuppression a cohort of swimmers were also able to mount an antibody response to pneumococcal vaccine equivalent to that of sedentary individuals. Observations of chronic suppression of aspects of host defence and the significant relationship between changes in mucosal immune parameters and URTI, provide a framework for assessment of the immune status of athletes. The underlying causes of upper respiratory tract distress symptoms may be infective, inflammatory or allergic in origin: a differential diagnosis has implications for treatment and management.

Exercise↗

Differences in immune responses induced by oral and rectal immunizations with Salmonella typhi Ty21a: evidence for compartmentalization within the common mucosal immune system in humans.

Based on the concept of the common mucosal immune system, immunization at various inductive sites can induce an immune response at other, remote mucosal surfaces. The immune responses elicited through rectal and oral routes of antigen delivery were compared with respect to (i) measurement of antibody responses in serum and various external secretions of the vaccinees and (ii) characterization of the nature and homing potentials of circulating antibody-secreting cells (ASC). Specific ASC appeared in the circulation in 4 of 5 volunteers after oral and 9 of 11 volunteers after rectal immunization with Salmonella typhi Ty21a. The kinetics, magnitude, and immunoglobulin isotype distribution of the ASC responses were similar in the two groups. In both groups, almost all ASC (99 or 95% after oral or rectal immunization, respectively) expressed alpha4 beta7, the gut homing receptor (HR), whereas L-selectin, the peripheral lymph node HR, was expressed only on 22 or 38% of ASC, respectively. Oral immunization elicited a more pronounced immune response in saliva and vaginal secretion, while rectal immunization was more potent in inducing a response in nasal secretion, rectum, and tears. No major differences were found in the abilities of the two immunization routes to induce a response in serum or intestinal secretion. Thus, the rectal antigen delivery should be considered as an alternative to the oral immunization route. The different immune response profiles found in various secretions after oral versus rectal antigen administration provide evidence for a compartmentalization within the common mucosal immune system in humans.

Administration, Oral↗

Integrative multi-omics profiling deciphers tumor microenvironment heterogeneity and immunotherapy vulnerabilities in lung neuroendocrine carcinomas.

INTRODUCTION: Lung neuroendocrine carcinomas (Lu-NECs) are rare, highly aggressive lung tumors with poor prognosis and limited therapeutic options. Understanding the tumor immune microenvironment (TIME) is crucial towards personalized therapeutic strategies. OBJECTIVES: This study aims to systematically characterize the heterogeneity and complexity of the TIME in Lu-NECs by integrating proteomic, transcriptomic, and genomic data. METHODS: We performed comprehensive immune-proteomic profiling of 76 Lu-NECs across diverse histopathological subtypes to elucidate intra-tumoral TIME heterogeneity at the proteomic level. Validation was conducted in multiple independent cohorts, including 112 Lu-NECs using immunohistochemistry, 147 Lu-NECs, and 17 small cell lung carcinoma samples using transcriptomics. We integrated proteomic, transcriptomic, genomic, and clinical data to assess molecular, immunological, and clinical features, as well as therapeutic vulnerabilities across different immune subtypes. RESULTS: We delineated the immuno-proteomic landscape of Lu-NECs and identified two major immuno-proteomic clusters with distinct immunological, molecular, and clinical characteristics. IPC1 was characterized by high immune cell infiltration, while IPC2 exhibited sparse immune cell presence. Genomic analysis revealed distinct mutational patterns, with IPC1 showing a higher incidence of APOBEC-associated mutation signatures and IPC2 being enriched for mutations associated with defective DNA mismatch repair and tobacco-related mutagens. Functional analyses indicated that IPC1 was related to immune and oncogenic signaling activity, whereas IPC2 was associated with cancer stemness and proliferation-related features. Furthermore, IPC1 and IPC2 demonstrated histological subtype-specific clinical benefits from postoperative chemotherapy. Finally, we developed a machine learning model (iPROM) to predict Lu-NECs immune classification and improve risk stratification, which was validated across multiple independent cohorts. CONCLUSIONS: This study advances the understanding of the tumor immune microenvironment in Lu-NECs through multi-omics characterization and highlights potential personalized therapeutic vulnerabilities tailored to the specific immune landscapes of Lu-NECs.

Humans↗

CpG-modified plasmid DNA encoding flagellin improves immunogenicity and provides protection against Burkholderia pseudomallei infection in BALB/c mice.

The plasmid DNA encoding the fliC gene of Burkholderia pseudomallei combined with CpG oligodeoxynucleotide (ODN) was injected intramuscularly into BALB/c mice, resulting in the increased production of certain humoral antibodies and flagellin-specific spleen cell clonal expansion. CpG ODN, as an immunoadjuvant, was added to the plasmid containing the fliC gene in order to obtain ongoing expression in muscle for a long period. Functional expression of flagellin from the constructed CpG-modified plasmid in transfected peritoneal exudate cells of BALB/c mice was shown by reverse transcription-PCR and Western blotting. Furthermore, BALB/c mice immunized with the modified plasmid had relatively higher resistance to B. pseudomallei infection in vivo than did mice immunized with unmodified plasmid DNA. The time course of restricted bacterial growth in spleen and liver and changes in the cytokine profiles of immunized mice suggested that the stimulated phagocytic cells would be able to kill the bacteria eventually, possibly as a consequence of the induction of Th-1-type immune polarization in vivo. Th-1-type immune polarization was detected in response to flagellin induction in mice immunized with CpG-modified plasmid DNA by the appearance of increased levels of immunoglobulin G2a antibodies and gamma interferon-secreting cells specific to flagellin. The exogenous CpG motifs added to the fliC gene would contribute to an adjuvant-like response that enhances the flagellin-specific immunogenicity and provides protection against B. pseudomallei infection. This CpG-modified plasmid DNA vaccination is an important potential strategy that should be developed to protect against melioidosis.

Adjuvants, Immunologic↗

Expression of simian immunodeficiency virus Nef protein in CD4+ T cells leads to a molecular profile of viral persistence and immune evasion.

The Nef protein of human immunodeficiency virus and simian immunodeficiency virus is expressed early in infection and plays an important role in disease progression in vivo. In addition, Nef has been shown to modulate cellular functions. To decipher Nef-mediated changes in gene expression, we utilized DNA microarray analysis to elucidate changes in gene expression in a Jurkat CD4+ T-cell line stably expressing SIV-Nef protein under the control of an inducible promoter. Our results showed that genes associated with antigen presentation including members of the T-cell receptor and major histocompatibility class 1 complex were consistently down-regulated at the transcript level in SIV-Nef-expressing cells. In addition, Nef induced a transcriptional profile of cell-cycle-related genes that support the survival of Nef-expressing cells. Furthermore, Nef enhanced the transcription of genes encoding enzymes and factors that catalyze the biosynthesis of membrane glycolipids and phospholipids. In conclusion, gene expression profiling showed that SIV-Nef induces a transcriptional profile in CD4+ T cells that promotes immune evasion and cell survival, thus facilitating viral persistence.

Antigen Presentation↗

Effects of re-immunization of heifers against inhibin on hormonal profiles and ovulation rate.

To study the effect of re-immunization against inhibin on ovarian response and hormonal profiles, Japanese beef heifers (n = 5) were re-immunized three times with inhibin vaccine (recombinant ovine inhibin alpha-subunit in oil emulsion, 125 microg ml(-1)) one year after the primary immunization. Control heifers (n = 5) were injected with placebo (Montanide: Marcol adjuvant alone). Oestrous cycles were synchronized by using prostaglandin F2alpha (PGF2alpha) and ovarian response was monitored daily by ultrasonography. Blood samples were collected by jugular venipuncture for assessment of hormonal levels and inhibin antibody titres. In contrast to controls, inhibin re-immunized heifers generated antibodies against inhibin rapidly reaching a peak level 9 days after the first booster injection. The mean concentrations of FSH in re-immunized cows increased significantly in comparison with controls. In addition, there was a significant increase in oestradiol-17beta and progesterone levels in re-immunized cows compared with controls. Inhibin re-immunized heifers had a significant increase in small (> or =4 < 7 mm), medium (> or =7 < 10 mm) and large (> or =10 mm in diameter) sized follicles. Moreover, the mean ovulation rate was 5.0 +/- 1.1 after the third booster injection in re-immunized heifers compared with control heifers (single ovulation). These results clearly demonstrate that re-immunization of inhibin can be used to enhance ovarian follicular development and ovulation rate. Furthermore, the great number of follicles is a potential source of oocytes that could be harvested for in vitro fertilization and embryo transfer programmes.

Animals↗

Mononuclear cell subpopulations in preterm and full-term neonates: independent effects of gestational age, neonatal infection, maternal pre-eclampsia, maternal betamethason therapy, and mode of delivery.

Blood samples from 29 preterm (24-32 weeks of gestation) and 21 full-term (37-42 weeks of gestation) neonates were analysed for surface markers of lymphocyte subtypes and macrophages, and the effects of gestational age, neonatal infection, maternal pre-eclampsia, maternal betamethason therapy and mode of delivery were assessed with multiple regression analysis. Gestational age alone had few independent effects (increase in CD3+, CD8+CD45RA+, and CD11alpha+ cells, and decrease in CD14+, HLA-DR- cells) during the third trimester on the proportions of the immune cell subtypes studied. Neonatal infection and mother's pre-eclampsia had the broadest and very opposite kinds of effects on the profile of immune cells in the blood. Infection of the neonate increased the proportions of several 'immature' cells (CD11alpha-CD20+, CD40+CD19-, and CD14+HLA-DR-), whereas mother's pre-eclampsia decreased the proportions of naive cell types (CD4+CD8+, CD5+CD19+). In addition, neonatal infection increased the proportion of T cells (CD3+, CD3+CD25+, and CD4+/CD8+ ratio, and CD45RA+ cells), while maternal pre-eclampsia had a decreasing effect on the proportion of CD4+ cells, CD4+/CD8+ ratio, and proportions of CD11alpha+, CD14+ and CD14+HLA-DR+ cells. Maternal betamethason therapy increased the proportion of T cells (CD3+) and macrophages (CD14+, CD14+HLA-DR+), but decreased the proportion of natural killer (NK) cells. Caesarean section was associated with a decrease in the proportion of CD14+ cells. We conclude that the 'normal range' of proportions of different mononuclear cells is wide during the last trimester; further, the effect of gestational age on these proportions is more limited than the effects of other neonatal and even maternal factors.

Antigens, CD↗

Cyclin-dependent kinase 4 and 6 inhibitors and the breast cancer immune ecosystem: immune remodeling, resistance, and therapeutic reprogramming.

Cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6 inhibitors) combined with endocrine therapy have become a therapeutic backbone for hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer, yet durable disease control is frequently limited by intrinsic and acquired resistance. Canonical tumor-cell mechanisms, including retinoblastoma-pathway escape, cyclin E-cyclin-dependent kinase 2 (CDK2) activation, endocrine adaptation, and phosphoinositide 3-kinase (PI3K)-AKT-mechanistic target of rapamycin (mTOR) signaling, explain only part of this failure because they do not fully capture dynamic immune and stromal remodeling. Preclinical and translational studies indicate that early CDK4/6 inhibition can enhance antigen presentation, activate interferon-related programs, restrain regulatory T cells, and promote a T-cell-inflamed state. These effects are conditional and may not persist during prolonged treatment. Sustained therapy can instead drive heterogeneous resistant niches characterized by stromal remodeling, myeloid recruitment, checkpoint adaptation, and T-cell dysfunction. This immune-state dependence provides a rationale for immune checkpoint blockade, although clinical combinations have shown mixed efficacy and clinically relevant hepatic, pulmonary, and hematologic toxicities. Sequential or lead-in strategies therefore warrant prospective evaluation. Oxidative phosphorylation (OXPHOS) and redox adaptation may sustain selected resistant states and expose context-dependent ferroptotic vulnerabilities. Ferroptosis may connect tumor-cell killing with immune regulation, whereas nanomedicine may improve tumor-selective delivery. Both strategies remain largely preclinical and require further evaluation of pharmacokinetics, biodistribution, toxicity, manufacturability, and immune-cell safety. This Review distinguishes intrinsic from acquired resistance across interpatient, intratumoral, spatial, and temporal dimensions. It integrates tumor-cell escape with cytokine, immune, stromal, vascular, and metabolic remodeling and summarizes emerging therapeutic strategies. We further propose a candidate biomarker-informed framework that integrates genomic profiling, spatial immune architecture, circulating biomarkers, T-cell receptor (TCR) dynamics, transcriptomic and single-cell analyses, artificial intelligence (AI)-assisted multimodal integration, and longitudinal sampling. This framework is intended to support biomarker development and prospective trial design rather than current clinical decision-making, providing a translational basis for testing state-informed and sequence-aware therapeutic strategies.

Humans↗

Childhood immunization registries: gaps between knowledge and action among family practice physicians and pediatricians in Washington state, 1998.

OBJECTIVES: To assess the availability and use of Washington State's CHILD (Children's Health, Immunization, Linkages, and Development) Profile and other computerized immunization tracking systems, to determine physicians' attitudes about these systems, and to identify factors associated with using them. DESIGN: Randomized, population-based, cross-sectional survey. PARTICIPANTS: Washington family physician and pediatrician specialty organization members providing childhood immunizations in 1998 (N = 2472). MAIN OUTCOME MEASURE: Reported CHILD Profile and other computerized systems use. RESULTS: The adjusted response rate was 75% (n = 1331). Overall, 37.7% of respondents had heard of CHILD Profile, 6.3% used it, and 24.9% used other systems. Groups significantly more likely not to use computerized systems than referent pediatricians in areas fully implementing CHILD Profile were family physicians (adjusted odds ratio [aOR], 2.4; 95% confidence interval [CI], 1.4-4.0), private physicians (aOR, 8.0; 95% CI, 3.2-20.1), physicians taking fewest opportunities to immunize (aOR, 2.3; 95% CI, 1.4-3.7), and physicians practicing in local health jurisdiction areas with CHILD Profile marketing activity (aOR, 2.1; 95% CI, 1.2-3.9) or in those areas with little or no registry activity (aOR, 2.6; 95% CI, 1.6-4.4). Those with systems agreed that they save time (71.0%), make status checks easier (87.1%), and increase immunization coverage (88.6%). Those without systems agreed that they help practices (90.3%) and increase efficiency (76.5%), but fewer agreed that they reduce costs (30.2%). CONCLUSIONS: Although most physicians agreed that computerized systems are useful, few had them or used them. Provider-based systems can improve immunization coverage, but the feasibility and effectiveness of communitywide and statewide systems remain unexplored. Because these systems depend on participation, more understanding is needed to help organizations implement them. Interventions to increase availability and use should address provider and health organization needs.

Adult↗

Characterization of the serologic profile of children with human immunodeficiency virus infection: correlation with clinical status.

Serum samples from 28 children with symptomatic human immunodeficiency virus (HIV) infection were studied for the presence of HIV antigen. Their humoral immune response profile, including anti-HIV specific isotypic responses and neutralizing titers, was characterized. Additionally, serum specimens from 12 of these children were tested for their ability to mediate antibody-dependent cellular cytotoxicity (ADCC) against HIV envelope antigens. Analysis of our results showed that children with acquired immunodeficiency syndrome (AIDS) were much more likely to have serum antigenemia and an absence of anti-p24 antibodies than those with AIDS-related complex (ARC). A significant association was also noted between a more stable clinical status and a strong anti-p24 antibody response with detectable antibodies to other HIV antigens in multiple antibody subclasses. This suggests that the longitudinal evaluation of antigen/antibody profiles may aid in the assessment of prognosis for children with HIV infection. Sera from 6/6 patients with ARC and 4/6 patients with AIDS were able to mediate ADCC. No correlation was found between clinical status and the titers of neutralizing antibodies.

AIDS-Related Complex↗

Effects of TGF-beta2 on immune response-related gene expression profiles in the human corneal endothelium.

PURPOSE: To determine the effects of transforming growth factor (TGF)-beta2 on immune-response-related gene expression profiles in the stimulated human corneal endothelium (HCE). METHODS: A human complementary DNA (cDNA) expression array analysis was used to investigate the effects of TGF-beta2 on cultured HCE incubated with interleukin (IL)-1alpha and tumor necrosis factor (TNF)-alpha. Gene-specific semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) were performed to examine the gene expression patterns revealed by the cDNA expression array analysis. Moreover, the expression of newly identified genes in HCE was confirmed by RT-PCR in human donor corneas. RESULTS: cDNA expression array analysis and semiquantitative RT-PCR revealed that TGF-beta2 downregulated the expression of IL-6, growth-related (Gro)-alpha (CXCL1), monocyte chemotactic protein (MCP)-1 (CCL2), granulocyte-colony stimulating factor (G-CSF), and insulin-like growth factor binding protein (IGFBP)-5 and upregulated the expression of tissue inhibitor of metalloproteinase (TIMP)-1. ELISA confirmed TGF-beta2-mediated changes in the expression of IL-6, CXCL1, CCL2, G-CSF, IGFBP-5, and TIMP-1 at the protein level. CXCL1, G-CSF, and IGFBP-5 mRNAs were detected for the first time in the HCE of donor corneas. CONCLUSIONS: TGF-beta2 downregulates IL-6, CXCL1, CCL2, G-CSF, and IGFBP-5, and upregulates TIMP-1 in cultured HCE stimulated with proinflammatory cytokines, suggesting the immunomodulatory role of TGF-beta2 in the aqueous humor and the pathophysiological significance of TGF-beta2 in the anterior chamber of the eye.

Cell Culture Techniques↗

Evolution and heterogeneity of lethal metastatic bladder cancer subtypes.

Histological variation is a prognostic feature of metastatic urothelial cancer1-3, but its evolutionary trajectory remains poorly defined. We developed a metastatic bladder cancer rapid autopsy programme enriched in histological subtypes4 to profile individuals with terminal disease. Here by reconstructing the evolutionary histories of patient tumours, we show that metastasis-to-metastasis seeding is the dominant pattern of cancer spread and that increased polyclonal migration predicts poor prognosis. The burden, heterogeneity and timing of genomic alterations differ markedly among histological subtypes. Plasmacytoid and neuroendocrine variants develop early driver alterations associated with shorter survival. Mutational signature analyses and experimental models demonstrated that plasmacytoid tumours uniquely use the Fanconi anaemia pathway to mitigate chemotherapy-induced genomic scarring. Single-nucleus profiling revealed mixed cell states in histological subtypes and an association between transcriptional heterogeneity and patient survival. Characterization of the tumour microenvironment uncovered distinct immune states across subtypes, with plasmacytoid tumours exhibiting immune-inflamed profiles, whereas squamous tumours are predominantly immunosuppressive. Last, we demonstrate that post-mortem cell-free DNA captures genomic and transcriptional heterogeneity of the subtypes, which provides a potential strategy for noninvasive assessment of tumour identity and aggressiveness. Our results provide new insights into how tumour heterogeneity shapes the evolutionary history of disease progression in bladder cancer histological subtypes.

Journal Article↗

[Occupational exposure to hepatitis B virus in personnel of the S.S. Trinità Hospital in Borgomanero].

369 workers at the S.S. Trinità Hospital, Borgomanero - Health Unit 54 were screened for H.B.V. H.B.V. markers were found in 49.9% of whom 28% presented a profile of immunization, 1.9% were found to be chronic carriers of HBsAg, 18.1% were only positive for anti-HBc and 1.9% presented a doubtful serum profile that will require further study. Women and senior staff (in terms of both age and seniority of service) were most often affected. In view of the high rate of H.B.V. infection, preventive vaccination is though necessary to protect the workers' health.

Age Factors↗

Regulation of the trafficking of tumour-infiltrating dendritic cells by chemokines.

To anticipate and initiate immune responses, dendritic cells follow a migratory route from their recruitment as sentinels into tissues, including solid tumors, then to secondary lymphoid organs where they profile the immune response. Migratory capacities--and especially chemokine responsiveness--are therefore key elements in dendritic cell biology. Here, we will review our current knowledge about tumour-infiltrating dendritic cells and the chemokine-driven migration flows in and out from tumors. Then we will discuss the consequences of the interactions between dendritic cells and tumors and the perspectives for translating our experimental knowledge of manipulating dendritic cell migratory flows into anti-cancer therapies.

Cell Movement↗

1alpha,25-dihydroxyvitamin D3 increases IgA serum antibody responses and IgA antibody-secreting cell numbers in the Peyer's patches of pigs after intramuscular immunization.

Pigs were injected intramuscularly (i.m.) twice with human serum albumin (HSA) with or without 1alpha,25-dihydroxyvitamin D3[1alpha,25(OH)2D3] with a 5-week interval. The supplementation of 1alpha,25(OH)2D3 enhanced the HSA-specific IgA serum antibody response but decreased the IgM, IgG, IgG1 and IgG2 responses. Furthermore, higher numbers of HSA-specific IgA antibody-secreting cells were obtained in systemic lymphoid tissues (local draining lymph node, spleen and bone marrow) as well as in Peyer's patches and lamina propria of the gut (GALT). In addition, the in vivo mRNA expression for Th1 [interferon (IFN)-gamma, interleukin (IL-2)], Th2 (IL-4, IL-6 and IL-10) and Th3 [transforming growth factor (TGF)-beta] cytokines as well as the percentage of different cell subsets (CD2+, CD4+, CD8+, IgM+, MHC II+, CD25+) of monomorphonuclear cells from the local draining lymph node were determined at different time-points after the i.m. immunizations. Cytokine profiles did not resemble a typical Th-cytokine profile using 1alpha,25(OH)2D3: higher levels of IL-10 and significantly lower levels of IL-2 were observed the first day after the primary immunization. However, significantly higher levels of IL-2 and significantly lower levels of IFN-gamma were observed the first day after the second immunization. Furthermore, after the second immunization TGF-beta mRNA expression decreased more quickly in the 1alpha,25(OH)2D3 group. This difference became significant 7 days after the second immunization. One week later a significantly higher percentage of CD25+ cells was observed in this group, indicating more activated T and B cells using the steroid hormone. These results suggest that in pigs the addition of 1alpha,25(OH)2D3 to an intramuscularly injected antigen can enhance the antigen-specific IgA-response and prime GALT tissues, but the relation with cytokines and cell phenotype in the local draining lymph node needs further clarification.

Adjuvants, Immunologic↗

IFN-gamma-secreting Th cells regulate both the frequency and avidity of epitope-specific CD8+ T lymphocytes induced by peptide immunization: an ex vivo analysis.

CD8+ T lymphocytes are involved in protective immune responses to infected or tumor cells. In this report, we examined the regulation of antigen-specific CD8+ T cell frequency and avidity by distinct Th cell subsets. Peptide-specific CD8+ T cells were induced by immunization of mice with a MHC class I-restricted epitope, co-injected with a MHC class II-restricted epitope to recruit Th cells. CD8+ T cell responses were assessed directly ex vivo for lytic activity and IFN-gamma secretion using the enzyme-linked immunospot (ELISPOT) assay. Co-immunization in incomplete Freund's adjuvant (IFA) with three different helper peptides induced IFN-gamma- and IL-2-secreting Th cells, in the absence of IL-4 secretion, suggesting preferential Th1 profiles. Such immunization resulted in the increase of antigen-specific CD8+ T cell frequency, which was detected in blood as efficiently as in lymph nodes and spleen, and elicited high-avidity CD8+ T cells. We investigated whether these effects were dependent upon a particular Th profile. When alum was used instead of IFA, the production of IL-2 by Th cells was still significant, while the production of IFN-gamma was undetectable. Such Th cell activation failed to support an increase of antigen-specific CD8+ T cell frequency. Altogether, these results document in vivo the regulatory role played by Th cells in CD8+ T cell activation and may be relevant for the design of efficient vaccination schedules.

Amino Acid Sequence↗