scholarly journals Prediction and Validation of Immunogenic Domains of Pneumococcal Proteins Recognized by Human CD4+T Cells

2019 ◽  
Vol 87 (6) ◽  
Author(s):  
Martijn D. B. van de Garde ◽  
Els van Westen ◽  
Martien C. M. Poelen ◽  
Nynke Y. Rots ◽  
Cécile A. C. M. van Els
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Cell Clone ◽  
Bioinformatics Tool ◽  
Peripheral Blood Mononuclear ◽  
Necrosis Factor Alpha ◽  
T Cell Clone ◽  
Tnf Α ◽  
Ifn Γ

ABSTRACTCD4+T-cell mechanisms are implied in protection against pneumococcal colonization; however, their target antigens and function are not well defined. In contrast to high-throughput protein arrays for serology, basic antigen tools for CD4+T-cell studies are lacking. Here, we evaluate the potential of a bioinformatics tool forin silicoprediction of immunogenicity as a method to reveal domains of pneumococcal proteins targeted by human CD4+T cells. For 100 pneumococcal proteins, CD4+T-cell immunogenicity was predicted based on HLA-DRB1 binding motifs. For 20 potentially CD4+T-cell immunogenic proteins, epitope regions were verified by testing synthetic peptides in T-cell assays using peripheral blood mononuclear cells from healthy adults. Peptide pools of 19 out of 20 proteins evoked T-cell responses. The most frequent responses (detectable in ≥20% of donors tested) were found to SP_0117 (PspA), SP_0468 (putative sortase), SP_0546 (BlpZ), SP_1650 (PsaA), SP_1923 (Ply), SP_2048 (conserved hypothetical protein), SP_2216 (PscB), and SPR_0907 (PhtD). Responding donors had diverging recognition patterns and profiles of signature cytokines (gamma interferon [IFN-γ], tumor necrosis factor alpha [TNF-α], interleukin-13 [IL-13], and/or IL-17A) against single-epitope regions. Natural HLA-DR-restricted presentation and recognition of a predicted SP_1923-derived epitope were validated through the isolation of a CD4+T-cell clone producing IFN-γ, TNF-α, and IL-17A in response to the synthetic peptide, whole protein, and heat-inactivated pneumococcus. This proof of principle for a bioinformatics tool to identify pneumococcal protein epitopes targeted by human CD4+T cells provides a peptide-based strategy to study cell-mediated immune mechanisms for the pneumococcal proteome, advancing the development of immunomonitoring assays and targeted vaccine approaches.

scholarly journals Multifunctional Human Immunodeficiency Virus (HIV) Gag-Specific CD8+ T-Cell Responses in Rectal Mucosa and Peripheral Blood Mononuclear Cells during Chronic HIV Type 1 Infection

2007 ◽  
Vol 81 (11) ◽  
pp. 5460-5471 ◽  
Author(s):  
J. William Critchfield ◽  
Donna Lemongello ◽  
Digna H. Walker ◽  
Juan C. Garcia ◽  
David M. Asmuth ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Rectal Mucosa ◽  
Peripheral Blood Mononuclear ◽  
Tnf Α ◽  
Immunodeficiency Virus ◽  
Ifn Γ ◽  
Hiv 1

ABSTRACT The intestinal tract is a lymphocyte-rich site that undergoes severe depletion of memory CD4+ T cells within days of simian immunodeficiency virus or human immunodeficiency virus type 1 (HIV-1) infection. An ensuing influx of virus-specific CD8+ T cells, which persist throughout the chronic phase of infection, has also been documented in the gastrointestinal tract. However, little is known of the functionality of these effector cells or their relationship to the disease course. In this study, we measured CD8+ T-cell responses to HIV-1 peptides in paired rectal and blood samples from chronically infected patients. In both blood and rectum, there was an immunodominant CD8+ T-cell response to HIV Gag compared to Pol and Env (P < 0.01). In contrast, cytomegalovirus pp65 peptides elicited gamma interferon (IFN-γ) secretion strongly in peripheral blood mononuclear cells (PBMC) but weakly in rectal CD8+ T cells (P = 0.015). Upon stimulation with HIV peptides, CD8+ T cells from both sites were capable of mounting complex responses including degranulation (CD107 expression) and IFN-γ and tumor necrosis factor alpha (TNF-α) production. In rectal tissue, CD107 release was frequently coupled with production of IFN-γ or TNF-α. In patients not on antiretroviral therapy, the magnitude of Gag-specific responses, as a percentage of CD8+ T cells, was greater in the rectal mucosa than in PBMC (P = 0.054); however, the breakdown of responding cells into specific functional categories was similar in both sites. These findings demonstrate that rectal CD8+ T cells are capable of robust and varied HIV-1-specific responses and therefore likely play an active role in eliminating infected cells during chronic infection.

scholarly journals Multifunctional, TNF-α and IFN-γ-Secreting CD4 and CD8 T Cells and CD8High T Cells Are Associated With the Cure of Human Visceral Leishmaniasis

2021 ◽  
Vol 12 ◽  
Author(s):  
Lorranny Santana Rodrigues ◽  
Aline Silva Barreto ◽  
Lays Gisele Santos Bomfim ◽  
Marcos Couto Gomes ◽  
Nathalia Luisa Carlos Ferreira ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Visceral Leishmaniasis ◽  
Mononuclear Cells ◽  
Healing Process ◽  
T Cell Response ◽  
Peripheral Blood Mononuclear ◽  
Tnf Α ◽  
Ifn Γ

Visceral leishmaniasis (VL) is a chronic and often fatal disease caused by protozoans of the genus Leishmania that affects millions of people worldwide. Patients with symptomatic VL have an impaired anti-Leishmania-specific CD4+ T-cell response, which is reversed after clinical cure. In contrast, the quality of the CD4+ and CD8+ T-cell responses involved in resistance and/or cure of VL relies on the capability of these cells to activate polyfunctional and memory responses, which are associated with the simultaneous production of three cytokines: IFN-γ, IL-2, and TNF-α. Models for the development of CD4 and CD8 T-cell quality in memory and protection to leishmaniasis have been described previously. We aimed to assess the functionality of the T cells involved in the recovery of the immune suppression throughout the VL treatment. Therefore, we cultured peripheral blood mononuclear cells (PBMCs) from VL patients and healthy controls in vitro with soluble Leishmania antigen (SLA). Cell surface markers and intracellular cytokine production were determined on days 7, 14, 21, 30, 60, 90, and 180 after the beginning of chemotherapy. We observed that the frequencies of CD4+TNF-α+IFN-γ+ and the multifunctional CD4+IL-2+TNF-α+IFN-γ+, together with CD4+TNF-α+ and CD4+IFN-γ+ T cells, increased throughout and at the end of the treatment, respectively. In addition, enhanced frequencies of CD8+IL-2+TNF-α+IFN-γ+ and CD8+TNF-α+IFN-γ T cells were also relevant in the healing process. Noteworthy, the frequencies of the CD4+ and CD8 central-memory T cells, which produce IL-2, TNF-α, and IFN-γ and ensure the memory response against parasite reinfection, are significantly enhanced in cured patients. In addition, the subset of the non-functional CD8Low population is predominant in VL untreated patients and decreases along the chemotherapy treatment. In contrast, a CD8High subset increased towards the cure. Furthermore, the cure due to treatment with meglumine antimoniate or with liposomal amphotericin B was associated with the recovery of the T-cell immune responses. We described the evolution and participation of functional T cells during the treatment of patients with VL. Our results disclosed that the clinical improvement of patients is significantly associated with the participation of the CD4+ and CD8+ cytokine-secreting T cells.

scholarly journals The Secreted Protein Rv1860 of Mycobacterium tuberculosis Stimulates Human Polyfunctional CD8+T Cells

2016 ◽  
Vol 23 (4) ◽  
pp. 282-293 ◽  
Author(s):  
Vijaya Satchidanandam ◽  
Naveen Kumar ◽  
Sunetra Biswas ◽  
Rajiv S. Jumani ◽  
Chandni Jain ◽  
...  
Keyword(s):  
T Cells ◽  
Mycobacterium Tuberculosis ◽  
T Cell ◽  
Mononuclear Cells ◽  
Interleukin 10 ◽  
T Cell Response ◽  
Peripheral Blood Mononuclear ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
Latent Tb Infection

ABSTRACTWe previously reported that Rv1860 protein fromMycobacterium tuberculosisstimulated CD4+and CD8+T cells secreting gamma interferon (IFN-γ) in healthy purified protein derivative (PPD)-positive individuals and protected guinea pigs immunized with a DNA vaccine and a recombinant poxvirus expressing Rv1860 from a challenge with virulentM. tuberculosis. We now show Rv1860-specific polyfunctional T (PFT) cell responses in the blood of healthy latentlyM. tuberculosis-infected individuals dominated by CD8+T cells, using a panel of 32 overlapping peptides spanning the length of Rv1860. Multiple subsets of CD8+PFT cells were significantly more numerous in healthy latently infected volunteers (HV) than in tuberculosis (TB) patients (PAT). The responses of peripheral blood mononuclear cells (PBMC) from PAT to the peptides of Rv1860 were dominated by tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10) secretions, the former coming predominantly from non-T cell sources. Notably, the pattern of the T cell response to Rv1860 was distinctly different from those of the widely studiedM. tuberculosisantigens ESAT-6, CFP-10, Ag85A, and Ag85B, which elicited CD4+T cell-dominated responses as previously reported in other cohorts. We further identified a peptide spanning amino acids 21 to 39 of the Rv1860 protein with the potential to distinguish latent TB infection from disease due to its ability to stimulate differential cytokine signatures in HV and PAT. We suggest that a TB vaccine carrying these and other CD8+T-cell-stimulating antigens has the potential to prevent progression of latentM. tuberculosisinfection to TB disease.

scholarly journals The Role of β-Catenin in Th1 Immune Response against Tuberculosis and Profiles of Expression in Patients with Pulmonary Tuberculosis

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Kunlong Xiong ◽  
Jinxia Niu ◽  
Ruijuan Zheng ◽  
Zhonghua Liu ◽  
Yanzheng Song ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Mononuclear Cells ◽  
Cd4 T Cell ◽  
Cell Frequency ◽  
Tnf Α ◽  
Ifn Γ

β-Catenin is a key molecule of canonical Wnt/β-catenin pathway. Its roles and expression profiles in T cells of tuberculosis (TB) remain unclear. The aim of this study was to explore the role of β-catenin in CD4+ T cells and its expression characteristics in patients with pulmonary tuberculosis (PTB). In this study, CD4+ T cell-specific β-catenin conditional knockout mice (β-CAT-cKO mice) were aerosol infected with Mycobacteria tuberculosis (Mtb) H37RV with wild-type mice as controls. Four weeks after infection, the mRNA expression of IFN-γ, TNF-α, and TCF-7 in the lungs of mice was measured. CD4, CD8, β-catenin, IFN-γ, and TNF-α in mononuclear cells from the lungs and spleens were measured by flow cytometry, and the pathological changes of lungs were also observed. Patients with PTB were enrolled, with blood samples collected and PBMCs isolated. The expressions of β-catenin, IFN-γ, TNF-α, and PD-1 in CD4+ and CD8+ T cells were measured by flow cytometry. Results showed a decreased frequency of and reduced IFN-γ/TNF-α mRNA expression and secretion by CD4+ T cells in the lungs of infected β-CAT-cKO mice compared with infected wild-type controls, and only slightly more inflammatory changes were observed in the lungs. β-catenin expressions in CD4+ and CD8+ T cells were significantly decreased in blood cells of patients with severe PTB compared with those in mild PTB. The stimulation of peripheral blood mononuclear cells (PBMCs) with lithium chloride (LiCl), a stimulant of β-catenin, resulted in the increase in CD4+ T cell frequency, as well as their secretion of IFN-γ and TNF-α. β-Catenin demonstrated a moderately positive correlation with PD-1 in CD4+ T cells. β-Catenin along with PD-1 and IFN-γ in CD4+ T cells had a high correlation with those in CD8+ T cells. In conclusion, β-catenin may be involved in the regulation of Th1 response and CD4+ T cell frequency in TB.

scholarly journals Protective and Pathological Functions of CD8+T Cells in Leishmania braziliensis Infection

2014 ◽  
Vol 83 (3) ◽  
pp. 898-906 ◽  
Author(s):  
Thiago Marconi Cardoso ◽  
Álvaro Machado ◽  
Diego Luiz Costa ◽  
Lucas P. Carvalho ◽  
Adriano Queiroz ◽  
...  
Keyword(s):  
T Cells ◽  
Mononuclear Cells ◽  
Granzyme B ◽  
Delayed Type Hypersensitivity ◽  
Leishmania Braziliensis ◽  
Peripheral Blood Mononuclear ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
Factor Alpha ◽  
Ifn Γ

Cutaneous leishmaniasis (CL) caused byLeishmania braziliensisis characterized by a strong Th1 response that leads to skin lesion development. In areas whereL. braziliensistransmission is endemic, up to 15% of healthy subjects have tested positive for delayed-type hypersensitivity to soluble leishmania antigen (SLA) and are considered to have subclinical (SC) infection. SC subjects produce less gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α) than do CL patients, but they are able to control the infection. The aim of this study was to characterized the role of CD8+T cells in SC infection and in CL. Peripheral blood mononuclear cells (PBMC) were stimulated with SLA to determine the frequencies of CD4+IFN-γ+and CD8+IFN-γ+T cells. Monocytes from PBMC were infected withL. braziliensisand cocultured with CD8+T cells, and the frequencies of infected monocytes and levels of cytotoxicity markers, target cell apoptosis, and granzyme B were determined. The frequency of CD8+IFN-γ+cells after SLA stimulation was higher for SC individuals than for CL patients. The frequency of infected monocytes in SC cells was lower than that in CL cells. CL CD8+T cells induced more apoptosis of infected monocytes than did SC CD8+T cells. Granzyme B production in CD8+T cells was higher in CL than in SC cells. While the use of a granzyme B inhibitor decreased the number of apoptotic cells in the CL group, the use of z-VAD-FMK had no effect on the frequency of these cells. These results suggest that CL CD8+T cells are more cytotoxic and may be involved in pathology.

"Tien-Hsien Liquid" Can Modulate Antigen-Stimulated Cytokine Production by T-Cells Isolated from Patients with Recurrent Aphthous Ulcerations

2005 ◽  
Vol 33 (04) ◽  
pp. 559-571 ◽  
Author(s):  
Andy Sun ◽  
Jean-San Chia ◽  
Won-Bo Wang ◽  
Chun-Pin Chiang
Keyword(s):  
T Cells ◽  
Mononuclear Cells ◽  
Cytokine Production ◽  
Interferon Γ ◽  
Enzyme Linked Immunosorbent Assay ◽  
Peripheral Blood Mononuclear ◽  
Tnf Α ◽  
Ifn Γ ◽  
Factor Α ◽  
Necrosis Factor

Recurrent aphthous ulcerations (RAU) represent a common oral mucosal disease with altered humoral and cellular immunities. Tien-Hsien liquid (THL) is an extract of Chinese medicinal herbs with immunomodulating effects. Our previous study found that THL can modulate the antigen-stimulated proliferative response of peripheral blood mononuclear cells and T-cells isolated from RAU patients. In this study, we further tested whether THL can modulate the antigen-stimulated cytokine production by T-cells isolated from RAU patients. To achieve this goal, T-cells isolated from 19 RAU patients were incubated with phytohemagglutinin (PHA), glutaraldehyde-inactivated tetanus toxoid (TT), glucosyltransferase D (GtfD), or antigens of Streptococcus mutans in the presence or absence of THL. The levels of interleukin (IL)-2, interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), IL-6, or IL-10 in the supernatants of T-cell cultures were measured by cytokine enzyme-linked immunosorbent assay (ELISA) kits. We found that THL significantly increased the PHA- or TT-stimulated TNF-α, IL-6, and IL-10 production by T-cells isolated from RAU patients. However, THL could also significantly decrease the TT-stimulated IL-2 production, the GtfD-stimulated IL-2, TNF-α, IL-6 and IL-10 production, and the S. mutans-stimulated IFN-γ, TNF-α, and IL-10 production by T-cells isolated from RAU patients. These results indicate that THL can modulate the antigen-stimulated cytokine production by T-cells isolated from RAU patients. Because RAU is probably a Thl-mediated disease with elevated levels of IL-2, IFN-γ, TNF-α and IL-6 in either the patient's sera or oral lesions and these increased levels of cytokines can be reduced by THL, we suggest that THL may be a potential immunoceutical agent for treatment of RAU.

scholarly journals Complex T Cell Interactions Contribute to Helicobacter pylori Gastritis in Mice

2012 ◽  
Vol 81 (3) ◽  
pp. 740-752 ◽  
Author(s):  
Brian M. Gray ◽  
Clinton A. Fontaine ◽  
Sara A. Poe ◽  
Kathryn A. Eaton
Keyword(s):  
T Cells ◽  
Helicobacter Pylori ◽  
T Cell ◽  
Published Data ◽  
Proinflammatory Response ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
Tnf Α ◽  
Ifn Γ ◽  
H Pylori

ABSTRACTDisease due to the gastric pathogenHelicobacter pylorivaries in severity from asymptomatic to peptic ulcer disease and cancer. Accumulating evidence suggests that one source of this variation is an abnormal host response. The goal of this study was to use a mouse model ofH. pylorigastritis to investigate the roles of regulatory T cells (Treg) as well as proinflammatory T cells (Th1 and Th17) in gastritis, gastric T cell engraftment, and gastric cytokine production. Our results support published data indicating that severe gastritis in T cell recipient mice is due to failure of Treg engraftment, that Treg ameliorate gastritis, and that the proinflammatory response is attributable to interactions between several cell subsets and cytokines. We confirmed that gamma interferon (IFN-γ) is essential for induction of gastritis but showed that IFN-γ-producing CD4 T cells are not necessary. Interleukin 17A (IL-17A) also contributed to gastritis, but to a lesser extent than IFN-γ. Tumor necrosis factor alpha (TNF-α) and IL-17F were also elevated in association with disease. These results indicate that whileH. pylori-specific CD4+T cells and IFN-γ are both essential for induction of gastritis due toH. pylori, IFN-γ production by T cells is not essential. It is likely that other proinflammatory cytokines, such as IL-17F and TNF-α, shown to be elevated in this model, also contribute to the induction of disease. We suggest that gastritis due toH. pyloriis associated with loss of immunoregulation and alteration of several cytokines and cell subsets and cannot be attributed to a single immune pathway.

scholarly journals Isolation of a T-Cell Clone Showing HLA-DRB1*0405-Restricted Cytotoxicity for Hematopoietic Cells in a Patient With Aplastic Anemia

Blood ◽  
1997 ◽  
Vol 89 (10) ◽  
pp. 3691-3699 ◽  
Author(s):  
Shinji Nakao ◽  
Akiyoshi Takami ◽  
Hideyuki Takamatsu ◽  
Weihua Zeng ◽  
Naomi Sugimori ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Aplastic Anemia ◽  
Mononuclear Cells ◽  
Cell Clone ◽  
Cytotoxic T Cells ◽  
Hematopoietic Cells ◽  
T Cell Clone ◽  
Cd34 Cells

Abstract The existence of T cells capable of inhibiting in vitro hematopoiesis has been shown in aplastic anemia (AA), although whether such inhibition is mediated by a specific immune reaction involving an HLA allele remained unknown. We isolated a CD4+ Vβ21+ T-cell clone that was most dominant among Vβ21+ T cells in the bone marrow (BM) of an AA patient whose HLA-DRB1 alleles included 1501 and 0405. The T-cell clone named NT4.2 lysed an autologous Epstein-Barr virus-transformed lymphoblastoid cell line (LCL) and phytohemagglutinin-stimulated lymphocytes (PHA-blasts) as well as allogeneic LCLs sharing HLA-DRB1*0405. Cytotoxicity against LCL cells and PHA-blasts by NT4.2 was blocked by anti–HLA-DR monoclonal antibody (MoAb) or anti-CD3 MoAb. NT4.2 also lysed autologous BM mononuclear cells enriched with CD34+ cells that had been cultured for one week in the presence of colony-stimulating factors as well as allogeneic CD34+ cells of a normal individual carrying HLA-DRB1*0405, cultured in the same way. Moreover, NT4.2 strongly inhibited colony formation by hematopoietic progenitor cells derived from cultured CD34+ cells sharing HLA-DRB1*0405. These results indicate that the AA patient has T cells capable of killing hematopoietic cells in an HLA-DRB1*0405-restricted manner and that such cytotoxic T cells may contribute to the pathogenesis of AA.

scholarly journals Chlamydia muridarum T-Cell Antigens Formulated with the Adjuvant DDA/TDB Induce Immunity against Infection That Correlates with a High Frequency of Gamma Interferon (IFN-γ)/Tumor Necrosis Factor Alpha and IFN-γ/Interleukin-17 Double-Positive CD4+ T Cells

2010 ◽  
Vol 78 (5) ◽  
pp. 2272-2282 ◽  
Author(s):  
Hong Yu ◽  
Xiaozhou Jiang ◽  
Caixia Shen ◽  
Karuna P. Karunakaran ◽  
Janina Jiang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Interleukin 17 ◽  
Double Positive ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
T Cell Antigens ◽  
Factor Alpha ◽  
Ifn Γ ◽  
Necrosis Factor

ABSTRACT Major impediments to developing a Chlamydia vaccine lie in identifying immunologically relevant T-cell antigens and delivery in a manner to stimulate protective immunity. Using an immunoproteomic approach, we previously identified three immunodominant Chlamydia T-cell antigens (PmpG-1, PmpE/F-2, and RplF). Because RplF has high homology to a human ortholog, it may not be suitable for human vaccine development. Therefore, in this study, we evaluated protection against Chlamydia infection in the genital tract in C57BL/6 mice immunized with Chlamydia-specific membrane proteins PmpG-1, PmpE/F-2, and major outer membrane protein (MOMP; as a reference) or a combination of them formulated with one of three adjuvants, CpG oligodeoxynucleotide (CpG-ODN), AbISCO-100 (AbISCO), or DDA/TDB (dimethyldioctadecylammonium bromide/d-(+)-trehalose 6,6′-dibehenate). The results show that immunization with the CpG-ODN formulation failed to provide protection against Chlamydia infection; the AbISCO formulation conferred moderate protection, and the DDA/TDB formulation showed the highest degree of protective efficacy. The combination of PmpG-1, PmpE/F-2, and MOMP proteins formulated with DDA/TDB exhibited the greatest degree of protection among all vaccine groups studied. Moreover, this vaccine combination also engendered significant protection in BALB/c mice, which have a different major histocompatibility complex (MHC) background. We measured cell-mediated immune cytokine responses in mice immunized with PmpG-1 mixed with each of the three adjuvants. The results demonstrate that mice immunized with the DDA/TDB formulation induced the strongest gamma interferon (IFN-γ) and interleukin-17 (IL-17) responses, characterized by the highest frequency of IFN-γ/tumor necrosis factor alpha (TNF-α) and IFN-γ/IL-17 double-positive CD4+ T cells. In conclusion, a Chlamydia vaccine based on the recombinant proteins PmpG-1, PmpE/F-2, and MOMP delivered in a DDA/TDB adjuvant conferred protection against infection that correlated with IFN-γ/TNF-α and IFN-γ/IL-17 double-positive CD4+ T cells.

scholarly journals Cytokine Responses to Plasmodium falciparumLiver-Stage Antigen 1 Vary in Rainy and Dry Seasons in Highland Kenya

2000 ◽  
Vol 68 (9) ◽  
pp. 5198-5204 ◽  
Author(s):  
C. C. John ◽  
P. O. Sumba ◽  
J. H. Ouma ◽  
B. L. Nahlen ◽  
C. L. King ◽  
...  
Keyword(s):  
Rainy Season ◽  
Mononuclear Cells ◽  
Age Groups ◽  
Dry Season ◽  
Peripheral Blood Mononuclear ◽  
Necrosis Factor Alpha ◽  
Liver Stage ◽  
Cytokine Responses ◽  
Tnf Α ◽  
Ifn Γ

ABSTRACT Seasonal epidemics of malaria occur in highland areas of western Kenya where transmission intensity varies according to rainfall. This study describes the seasonal changes in cytokine responses toPlasmodium falciparum liver-stage antigen 1 (LSA-1) by children (≤17 years old) and adults (≥18 years old) living in such a highland area. Fourteen- to 24-mer peptides corresponding to the N- and C-terminal nonrepeat regions of LSA-1 stimulated production of interleukin-5 (IL-5), interleukin-10 (IL-10), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α) by peripheral blood mononuclear cells (PBMC) from 17 to 73% of individuals in both age groups in both seasons. IL-10 and TNF-α responses were more frequent during the high-transmission, rainy season than during the low-transmission, dry season (73 and 67% versus 17 and 25% response rates, respectively). In contrast, there was no seasonal change in the proportion of LSA-1-driven IFN-γ and IL-5 responses. Children produced less IFN-γ than adults, but IL-5, IL-10, and TNF-α levels were similar for both age groups. Depletion of CD8+ cells from PBMC decreased IFN-γ but increased IL-10 production. Individuals with LSA-1-stimulated IL-10 responses in the dry season were less likely to become reinfected in the subsequent rainy season than those without IL-10 responses (25% versus 49%;P = 0.083). These data support the notion that maintenance of LSA-1-driven IL-10 and TNF-α responses requires repeated and sustained exposure to liver-stage P. falciparum. In contrast, IFN-γ responses increase slowly with age but persist once acquired. CD8+ T cells are the major source of IFN-γ but may suppress production or secretion of IL-10.

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