Cytotoxic T Lymphocytes In Blood Research Articles

Human papilloma virus-16-specific CD8+ T-cell expansions characterize different clinical forms of lichen planus and not lichen sclerosus et atrophicus.

Lichen planus (LP) is a cutaneomucosal chronic inflammatory disease characterized by a CD8+ cytotoxic T-lymphocytes (CTL) infiltrate. In erosive oral LP, we found HPV16-specific activated CTL in lesions, supporting a pathogenic contribution of HPV16. Here, we investigated whether a similar scenario occurs in other clinical forms of LP and in lichen sclerosus et atrophicus (LSA), another chronic disease also affecting the mucosa and/or the skin. Blood CTL from LP and LSA patients expressed significant higher levels of granzyme B, perforin and CD107a proteins than healthy donors. Expansions of TCRVß3+ CTL, with presence of TCR clonotypes identical to those previously detected in erosive oral LP, were found both in blood and mucosal/skin lesions of LP, and not of LSA patients. These expansions were enriched with HPV16-specific CD8+ T-cells as shown by their recognition of the E711-20 immunodominant epitope. In LSA patients, the peripheral repertoire of CTL was oligoclonal for TCRVß6+ CTL. Finally, although patients with LP and LSA have developed antibodies against HPV16 capsid L1, antibodies against HPV16 E6 were only observed in patients with LP. Overall, our data collectively suggest an involvement of HPV16-specific CTL in different clinical forms of LP, not only in erosive oral LP, while a different scenario operates in LSA.

A split influenza vaccine formulated with a combination adjuvant composed of alpha-d-glucan nanoparticles and a STING agonist elicits cross-protective immunity in pigs

BackgroundSwine influenza A viruses (SwIAVs) pose an economic and pandemic threat, and development of novel effective vaccines is of critical significance. We evaluated the performance of split swine influenza A virus (SwIAV) H1N2 antigens with a plant-derived nanoparticle adjuvant alone (Nano-11) [Nano11-SwIAV] or in combination with the synthetic stimulator of interferon genes (STING) agonist ADU-S100 (NanoS100-SwIAV). Specific pathogen free (SPF) pigs were vaccinated twice via intramuscular (IM) or intradermal (ID) routes and challenged with a virulent heterologous SwIAV H1N1-OH7 virus.ResultsAnimals vaccinated IM or ID with NanoS100-SwIAV had significantly increased cross-reactive IgG and IgA titers in serum, nasal secretion and bronchoalveolar lavage fluid at day post challenge 6 (DPC6). Furthermore, NanoS100-SwIAV ID vaccinates, even at half the vaccine dose compared to their IM vaccinated counterparts, had significantly increased frequencies of CXCL10+ myeloid cells in the tracheobronchial lymph nodes (TBLN), and IFNγ+ effector memory T-helper/memory cells, IL-17A+ total T-helper/memory cells, central and effector memory T-helper/memory cells, IL-17A+ total cytotoxic T-lymphocytes (CTLs), and early effector CTLs in blood compared with the Nano11-SwIAV group demonstrating a potential dose-sparing effect and induction of a strong IL-17A+ T-helper/memory (Th17) response in the periphery. However, the frequencies of IFNγ+ late effector CTLs and effector memory T-helper/memory cells, IL-17A+ total CTLs, late effector CTLs, and CXCL10+ myeloid cells in blood, as well as lung CXCL10+ plasmacytoid dendritic cells were increased in NanoS100-SwIAV IM vaccinated pigs. Increased expression of IL-4 and IL-6 mRNA was observed in TBLN of Nano-11 based IM vaccinates following challenge. Furthermore, the challenge virus load in the lungs and nasal passage was undetectable in NanoS100-SwIAV IM vaccinates by DPC6 along with reduced macroscopic lung lesions and significantly higher virus neutralization titers in lungs at DPC6. However, NanoS100-SwIAV ID vaccinates exhibited significant reduction of challenge virus titers in nasal passages and a remarkable reduction of challenge virus in lungs.ConclusionsDespite vast genetic difference (77% HA gene identity) between the H1N2 and H1N1 SwIAV, the NanoS100 adjuvanted vaccine elicited cross protective cell mediated immune responses, suggesting the potential role of this combination adjuvant in inducing cross-protective immunity in pigs.Graphical

Mediastinal lymph node removal ameliorates cytotoxic T-lymphocyte functions in patients with non-small cell lung cancer.

Mediastinal lymph node (MLN) removal by video-assisted mediastinoscopic lymphadenectomy (VAMLA) for preoperative cancer staging was reported to be associated with increased survival. The aim of this study was to evaluate the immunologic effects of complete MLN removal by VAMLA on cytotoxic T lymphocyte (CTL) phenotype and function. Seventeen patients with non-small cell lung cancer (NSCLC) (stage cT1-4N0-3M0-1A) and 20 healthy participants were included in this study. Blood samples were collected before and 4 weeks after the procedure. Lymphocytes were isolated from the removed MLNs. CTL phenotypes and functions were evaluated by flow cytometry. Plasma levels of soluble programmed cell death protein 1 (sPD-1), soluble programmed cell death protein 1 ligand, and soluble CTL antigen 4 (sCTLA-4) were measured with enzyme-linked immunosorbent assay. The ratio of the immunosenescent CTLs (CD3+CD8+CD28-) was increased in peripheral blood and MLNs of the patients with NSCLC compared to controls (p = 0.037), and MLN removal did not change this ratio. PD-1 and CTL antigen 4 expressions were significantly reduced in peripheral blood CTLs after MLN removal by VAMLA (p = 0.01 and p = 0.01, respectively). Granzyme A expression was significantly reduced in the peripheral blood CTLs of the patients compared to controls (p = 0.006) and MLN removal by VAMLA significantly improved Granzyme A expression in CTLs (p = 0.003). Plasma concentrations of sPD-1 and sCTLA-4 remained unchanged after VAMLA. CTLs in the MLNs and peripheral blood of the patients with NSCLC had an immunosenescent phenotype, increased immune checkpoint receptor expression, and impaired cytotoxicity. MLN removal by VAMLA improved these phenotypic and functional characteristics of CTLs. These changes may explain the potential contribution of VAMLA to improved survival.

Amplification of Cord Blood-Derived Cytotoxic T Lymphocytes using HL-60 cell Derived Exosomes

IntroductionDendritic cell (DCs) based cytotoxic T lymphocytes (CTLs) are commonly used in immunotherapy due to their specificity. The selection of appropriate cell origin and tumor antigen is the key point. The objective was to culture DCs and CTLs simultaneously from cord blood, and deliver antigen information using tumor derived exosomes.Material and methodsExosomes were collected from the human promyelocytic leukemia cell line HL-60 using ultracentrifugation. Prepared DCs from adherent cord blood mononuclear cells (MNCs) using SCF, GM-CSF, and IN-4. TNF-α and microRNA removed tumor-exosome were used to induce DCs maturation. DCs matured in the presence of HL-60 cell membrane protein extract or no antigen were set as control. CTLs was cultured from non-adherent MNCs by adding IFN-γ, IL-15, SCF, FLT-3L, anti-CD3, anti-CD28 and IL-2. The CTLs were analyzed by flow cytometry, cytotoxicity experiments and ELISA.ResultsDCs can be obtained from cord blood and express costimulatory molecules. After 15 days, the total number of the cells expanded 26.3 times, and more than 82% of the cells expressed CD3+CD8+ in the most amplified HL-60-Ex-DCs-CTL group. These CD3+CD8+ T cells generated by HL-60-Ex-DCs displayed specific cytotoxicity towards HL-60 and low lethality towards unrelated BALL-1 cells. ELISA results showed that the expressions of TNF-α and IFN-γ in HL-60-Ex-DCs or HL-60mPr-DCs activated CTLs were upregulated compared with the control group.ConclusionsCord blood CTLs generated by HL-60 derived exosome activated DCs displayed specific cytotoxicity towards HL-60 promyelocytic leukemia cells. Therefore cord blood and tumor derived exosomes provided a good source for adoptive immunotherapy.

Sustainable Tumor-Suppressive Effect of iPSC-Derived Rejuvenated T Cells Targeting Cervical Cancers

Immunotherapy utilizing induced pluripotent stem cell (iPSC) technology has great potential. Functionally rejuvenated cytotoxic T lymphocytes (CTLs) can survive long-term as young memory T cells in vivo, with continuous tumor eradication. Banking of iPSCs as an unlimited “off-the-shelf” source of therapeutic T cells may be feasible. To generate safer iPSCs, we reprogrammed human papilloma virus type 16 (HPV16) E6-specific CTLs by Sendai virus vector without cotransduction of SV40 large T antigen. The iPSCs efficiently differentiated into HPV16-specific rejuvenated CTLs that demonstrated robust cytotoxicity against cervical cancer. The tumor-suppressive effect of rejuvenated CTLs was stronger and more persistent than that of original peripheral blood CTLs. These rejuvenated HPV16-specific CTLs provide a sustained tumor-suppressive effect even for epithelial cancers and constitute promising immunotherapy for cervical cancer.

Abstract B78: Co-potentiation of human T cells to identify subdominant tumor neoantigens from melanoma patients responding to immune checkpoint blockade

Abstract Malignant melanoma is the most aggressive form of skin cancer, accounting for 10,000 deaths annually. Largely resistant to conventional cytotoxic chemotherapy and radiation, immune checkpoint blockade (ICB) therapies have revolutionized patient care, accounting for partial or complete responses in up to 70% of patients. An important aspect of cancer elimination is activation of the cytotoxic T lymphocyte (CTL) response. Recent data suggest that ICB mediated broadening of the peripheral blood CTL repertoire correlates with good clinical outcomes. Thus, recent studies in cancer immunotherapy have focused on targeting tumor neoantigens (tNeoAg) with cancer vaccines for use in combination with ICB. Computational algorithm-driven predictions of immunogenic tNeoAgs yield vast numbers of potential peptide targets, only a fraction of which may be immunogenic in patients. This likely contributed to the modest success of cancer vaccines targeting predicted, high-avidity tNeoAgs, emphasizing the importance of identifying true tumor rejection antigens, including sub-dominant antigens, outside the scope of predictive models. In addition to promoting T cell-mediated tumor rejection, ICB often comes at the expense of treatment-induced immune-related adverse effects (irAE) that frequently require discontinuation of treatment. Modulation of ICB towards antitumor immunity and away from autoimmunity may dramatically improve the therapeutic index of modern cancer therapy. This appears feasible considering the clinical observation that antitumor efficacy does not correlate with type/severity of irAE, suggesting that the mechanisms of both processes, though likely related (CTL mediated), may not be identical. We aim to identify and separate non-cross-reacting antigenic targets mediating tumor rejection from those mediating irAEs to enable therapeutic interventions that maximize the efficacy of ICB, expanding tumor-specific CTLs with vaccines while minimizing irAEs through desensitization. We have access to samples from responding/nonresponding melanoma patients subjected to ICB with varying degrees of irAEs. We have designed an experimental approach that combines established mass spectrometry and sequencing techniques to identify peptides and matching TCR clones with a novel strategy that targets the TCR-associated CD3 complex to allow inclusion of subdominant antigens in our studies. T-cell “co-potentiation” is achieved when anti-CD3 monovalent Fabs induce a conformational change in the CD3 complex that sustains the T-cell response to weak antigenic stimulation. We have successfully used anti-human CD3 Fabs to co-potentiate in vitro the activation and subsequent response to weak peptide-HLA/TCR interactions of human T cells found in PBMCs isolated from healthy donors. Our preliminary data suggest T-cell co-potentiation may allow identification of ICB-induced CTL clones specific for subdominant tNeoAgs and irAE targets in patients with melanoma undergoing active immunotherapy. Citation Format: Laura Elsbernd, Alfreda Nelson, Hien Huynh, Michele Hoffmann, Christopher Parks, Wendy Nevala, Shari Sutor, Larry Pease, Adam Schrum, Diana Gil, Svetomir N. Markovic. Co-potentiation of human T cells to identify subdominant tumor neoantigens from melanoma patients responding to immune checkpoint blockade [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B78.

CYTOTOXIC LYMPHOCYTES: THE ROLE IN INFLAMMATION IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE EXACERBATION AND REMISSION

Background: Despite the number of publications related to the expression of surface antigens of periphery blood lymphocytes in chronic obstructive pulmonary disease (COPD), algorithm for interpreting of the results and implicating pathogenetic treatments still needs to be developed. Aim: To assess the role of cytotoxic lymphocytes in the maintaining of inflammation in COPD. Materials and methods: To examine immune status in 37 patients with COPD exacerbation or remission and 24 healthy donors (control group), blood cytotoxic T-lymphocytes and NK-cells contents were measured using indirect immunofluorescence method. Absolute and relative numbers of lymphocytes expressing CD3, CD4, CD8, CD16, CD20, CD23, CD25, CD54, CD71, CD72, HLA-DR, CD95 antigens, membrane immunoglobulins M (mIgM) and G (mIgG) were estimated. Results: In COPD., significantly increased numbers of blood cytotoxic lymphocytes were demonstrated independently from the disease stage (p < 0.001). During COPD exacerbation, significant elevations of CD4, CD8, CD20, CD72, NK-cells numbers, serum mIgM and mIgG were demonstrated. During remission, CD20 and CD72 content returned to normal, though, increased numbers of other cytotoxic cells persisted promoting inflammation and progressive damage of pulmonary and bronchial tissues. Conclusion: Observed changes may be due to excessive stimulation of T-cell component of immune system in COPD patients both in exacerbation and remission. Relative reduction of total T-lymphocyte numbers indicates non-specific (non-infectious) inflammation type. High cytotoxic potential of immune system results in pulmonary damage and promotes development of pneumosclerosis and emphysema.

CLINICAL AND IMMUNOLOGICAL CORRELATIONS IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE AND BRONCHIAL ASTHMA

Background: To improve differential diagnosis of chronic obstructive pulmonary disease (COPD) and bronchial asthma (BA), identification of new biological markers is needed. Aim: To differentiate between COPD and BA using modern immunological methods. Materials and methods: Surface markers of peripheral blood lymphocytes were studied in patients with COPD (n=37) and BA (n=49) exacerbation. Immunological status was also assessed in 24 healthy controls. Results: In both COPD and BA, typical inflammatory changes of T-lymphocytes, B-lymphocytes and NK-cells counts were found. Lymphocyte surface phenotype changes were significantly different in COPD and BA. In COPD, a significant elevation of blood cytotoxic T-lymphocytes (CD8+) up to 34% was demonstrated; on the contrary, in BA patients, cytotoxic T-lymphocytes (CD8+) decreased to 21%. CD16+ lymphocytes (NK-cells) were significantly increased (up to 33%) in COPD patients and corresponded to normal values in BA (~10%). Conclusion: Differences in biological markers in COPD and BA reflect distinct pathogenesis of the diseases and may be used for differential diagnosis.

Metronomic cyclophosphamide eradicates large implanted GL261 gliomas by activating antitumor Cd8+ T-cell responses and immune memory

Cancer chemotherapy using cytotoxic drugs can induce immunogenic tumor cell death; however, dosing regimens and schedules that enable single-agent chemotherapy to induce adaptive immune-dependent ablation of large, established tumors with activation of long-term immune memory have not been identified. Here, we investigate this issue in a syngeneic, implanted GL261 glioma model in immune-competent mice given cyclophosphamide on a 6-day repeating metronomic schedule. Two cycles of metronomic cyclophosphamide treatment induced sustained upregulation of tumor-associated CD8+ cytotoxic T lymphocyte (CTL) cells, natural killer (NK) cells, macrophages, and other immune cells. Expression of CTL- and NK–cell-shared effectors peaked on Day 6, and then declined by Day 9 after the second cyclophosphamide injection and correlated inversely with the expression of the regulatory T cell (Treg) marker Foxp3. Sustained tumor regression leading to tumor ablation was achieved after several cyclophosphamide treatment cycles. Tumor ablation required CD8+ T cells, as shown by immunodepletion studies, and was associated with immunity to re-challenge with GL261 glioma cells, but not B16-F10 melanoma or Lewis lung carcinoma cells. Rejection of GL261 tumor re-challenge was associated with elevated CTLs in blood and increased CTL infiltration in tumors, consistent with the induction of long-term, specific CD8+ T-cell anti-GL261 tumor memory. Co-depletion of CD8+ T cells and NK cells did not inhibit tumor regression beyond CD8+ T-cell depletion alone, suggesting that the metronomic cyclophosphamide-activated NK cells function via CD8a+ T cells. Taken together, these findings provide proof-of-concept that single-agent chemotherapy delivered on an optimized metronomic schedule can eradicate large, established tumors and induce long-term immune memory.

Effect of kurarinol on peripheral blood CTL surface PD-1 expression of patients with chronic hepatitis B

To explore the anti-viral mechanism of kurarinol through studying its influence on cytotoxic T lymphocyte (CTL) surface program death receptor-1 (PD-1) expression of patients with chronic hepatitis B (CHB). 69 cases of CHB, HBV DNA > or = 10(4) copies/ml, HBeAg positive, human leukocyte antigen (HLA)-A2 positive, alanine aminotransferase (ALT) > 2 x upper limit of normal value(ULN).69 cases were randomly divided into two groups:34 cases in treatment group,600 mg of kurarinol glucose injection was used for intravenous dripping, once a day, one month later, 200 mg of kurarinol capsule was used orally,three times a day and 200 mg of silybin meglumine tablet was used orally, three times a day. 35 cases in control group, only silibin meglumine tablet was used, method and dosage were the same as those of treatment group. Three months later, their peripheral blood HBV specific CTL surface PD-1 expression, non-specific CTL surface PD-1 expression and level of HBV specific CTL,HBV DNA and HBeAg negative rate and liver functions were analyzed and compared. 3 months after treatment, peripheral blood HBV specific CTL surface PD-1 expression of the treatment group decreased compared with that before treatment (t = 2.39, P < 0.05), it also decreased compared with that of the control group 3 months after treatment (t = 2.26, P < 0.05), HBV specific CTL increased compared with that before treatment( t = 3.01, P < 0.01), it also increased compared with that of the control group after treatment (t = 2.65, P < 0.05). There was no significant difference of non-specific CTL surface PD-1 expression compared with that before treatment (P > 0.05), and there was no significant difference compared with that of the control group after treatment (P > 0.05). HBV DNA of 11 cases (32.5%) turned negative ( HBV DNA < 500 copies/ ml), higher than that of the control group after treatment (2 cases, 5.71%) chi2 = 7.99, P < 0.01, HBeAg of 9 cases (26.47%) turned negative, higher than that of the control group after treatment (1 case, 2.86%), chi2 = 7.75, P < 0.01. Kurarinol can increase level of HBV specific CTL by down-regulating peripheral blood HBV specific CTL surface PD-1 expression of CHB patients, which may be one of the possible mechanisms that kurarinol can remove or inhibit HBV of CHB patients.

Know when to say when: Serial assessment of apoptosis and lymphocyte infiltrates with combined intraprostatic autologous dendritic cell immunotherapy/radiation therapy in high-risk prostate cancer.

149 Background: Previous work suggested combining local radiotherapy (XRT) with intratumoral syngeneic dendritic cell (DC) injection could result in apoptosis/cell death mediated induction of cytotoxic T lymphocytes (CTL) based anti-tumor immunity. However, the presence, timing, and effectiveness of effector CTL prior, during, and following combined XRT/intratumoral autologous DC injection in humans is unknown. Methods: Herein, we report on timing concerns of intraprostatic DC injection in vivo, in human; five HLA-A2+, high risk localized prostate cancer patients were treated on protocol using androgen suppression therapy (AS), external beam radiation therapy (EBRT, 45 Gy) followed by brachytherapy permanent interstitial implant with addition of autologous intraprostatic DC injections during EBRT, after fractions 5, 15, and 25 of 25. Multiple serial prostate biopsies were collected before initiation of treatment, during EBRT and at 3, 12, 24 and 36 months after completion of treatment. Biopsies were stained for CD3, CD4, CD8, and cleaved caspase 3, and evaluated in a blinded manner. Specific anti-tumor immunity was assessed via ELISpot IFN-gamma production by CTL stimulated by HLA-A2 peptides derived from sequences of proteins associated with prostate cancer. Results: Apheresis, DC injections, and biopsies were well tolerated. The pattern of distribution of CD8+ cells was consistent with prostate cancer antigen targeting, rather than non-specific organ infiltration. There was not immediate obvious intraprostratic infiltrate by CTL after DC injection in vivo, in humans. Measurable, induced increases in ELISpot titers in peripheral blood CTL were observed for some subjects and for some antigens, but non-specific immunity fluctuated. Conclusions: This initial translational experience demonstrates safety and timing of DC injection coordinated with combined AS and XRT. Design of future trials employing combination XRT and DC will consider timing concerns to match therapy-induced apoptosis/cell death. No significant financial relationships to disclose.

Immunomodulatory activities and subacute toxicity of a novel β-glucan from Paenibacillus polymyxa JB115 in rats

Subacute toxicity and immunopharmacological activities of β-glucan from P. polymyxa JB115 was evaluated in a 28-day feeding study in rats. The white blood cell count, red blood cell count, hematocrit, hemoglobin, thrombocytes (THR) and thrombocytocrit were significantly higher in male fed with β-glucan than control rats and the insignificant lower eosinophil count, mean corpuscular volume, mean cell hemoglobin and uninfected THR (uTHR) levels were observed in male whereas no marked changes in female rats. No other significant differences in serum chemistry and liver, kidney, and spleen weights were observed. The pathological changes and other abnormal indicators were not detected in urine. Female rats fed with diet supplemented with 0.01% β-glucan also showed marked increase in the percentage of blood cytotoxic T-lymphocytes compared to that of the control group while not significant differences in the percentage of blood B-lymphocytes. No adverse effects on general condition and behavior, growth, feed and water consumption and feed conversion efficiency were found. The results suggest that consumption of the novel β-1, 3/1, 6-glucan from P. polymyxa JB115 was not associated with any obvious toxic effects in rats, indicating its safety as a potential immunostimulant or as an adjuvant of some animal vaccines.

Clinical grade expansion of CD45RA, CD45RO, and CD62L-positive T-cell lines from HLA-compatible donors: High cytotoxic potential against AML and ALL cells

Identification of a clinical grade method for the ex vivo generation of donor-derived T cells cytotoxic against both myeloid and lymphoblastic cells still remains elusive. We investigated rapid generation and expansion of donor derived-allogeneic T-cell lines cytotoxic against patient leukemic cells. Acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL) blasts were cultured 5 days in Stem Span, granulocyte macrophage colony-stimulating factor, interleukin-4, and calcium ionophore. All B-precursor ALL (N22) and AML (N13), but not T-cell ALL (N3), differentiated into mature leukemia-derived antigen-presenting cells (LD-APC). All but one LD-APC generated cytotoxic T lymphocyte (CTL) from adult human leukocyte antigen (HLA)-identical (N8) or unrelated donors (N2). Upon in vitro culture, donor-derived CTL acquired a memory T phenotype, showing concomitant high CD45RA, CD45RO, CD62L expression. CD8(+) cells, but not CD4(+) cells, were granzyme, perforine, and interferon-gamma-positive. Pooled CD4(+) and CD8(+) cells were cytotoxic against leukemic blasts (32%, 30:1 E:T ratio), but not against autologous or patient-derived phytohemagglutinin blasts. LD-APC from five ALL patients were used to generate CTL from cord blood. A mixed population of CD4(+) and CD8(+) cells was documented in 54% of wells. T cells acquired classical effector memory phenotype and showed a higher cytotoxicity against leukemia blasts (47%, 1:1 E:T ratio). Adult and cord blood CTL showed a skewing from a complete T-cell receptor repertoire to an oligo-clonal/clonal pattern. Availability of these cells should allow clinical trials for salvage treatment of leukemia patients relapsing after allogeneic stem cell transplantation.

UVA1 radiation (340–400 nm) interferes with the perforin-granule system of CD8 hi+ cytotoxic T lymphocytes in vitro

UVA1-irradiation was introduced as an innovative and effective phototherapy of atopic dermatitis (AD) and other skin diseases. In AD, a defect of a central apoptosis inducing effector system involved in immunoregulation and immune defense, i.e., the system of perforin-granules in cytotoxic T lymphocytes (CTL), was recently reported: perforin-reduction and perforin-hyperreleasability. We now investigated UVA1-effects on the perforin-granule system in vitro. Peripheral blood CTLs were exposed in vitro to 10–100 J/cm 2 UVA1 (340–400 nm), and to 30–150 mJ/cm 2 UVB (280–315 nm) as a control. A time-dependent perforin-granule release was induced by phorbol 12-myristate 13-acetate (PMA) and ionomycin. This release was inhibited dose-dependently by UVA1, but not by UVB. An UVA1-dose dependent pattern of sensitive (80%) and insensitive (20%) individuals was found. The kinetics of perforin release in AD-CTLs, i.e. hyperreleasability, was normalized by 50 J/cm 2 UVA1 in vitro. Sodium azide as a quencher of reactive oxygen species prevented the UVA1-mediated inhibition of perforin-granule release. Our data demonstrate for the first time a dose- and wavelength-dependent UVA1-effect in vitro on a major effector system of cytotoxic lymphocytes, the system of perforin-granules. This might contribute to the further understanding of immunomodulatory UVA1-effects in vivo.

P-068 Comparison of tumor-infiltrating and peripheral blood cytotoxicT lymphocyte phenotypes in non-small cell lung cancer patients

P-068 Comparison of tumor-infiltrating and peripheral blood cytotoxicT lymphocyte phenotypes in non-small cell lung cancer patients

Imiquimod, a Toll-like receptor-7 agonist, induces perforin in cytotoxic T lymphocytes in vitro

Imiquimod (IMQ), an activator of Toll-like receptor-7 (TLR-7), induces by several routes a profound anti-viral and anti-tumor effect in vivo. Physiologically, the immune system is using perforin-containing granules of cytotoxic T lymphocytes (CTL) towards the same biological purpose. This functional synergism prompted our current experiments addressing the question whether IMQ may influence perforin-release and/or induce perforin in CTLs in vitro. In peripheral lymphocytes of healthy and diseased subjects, IMQ induced a significant increase of perforin + CTLs within 12 h in all experiments performed. This effect was most pronounced in CTLs of patients suffering from atopic dermatitis, a model disorder for subnormal perforin expression: as compared to perforin + CTLs detected at time point zero (100%), up to 270% of perforin + CTLs were induced by 2.5 μM/ml IMQ. Perforin release from peripheral blood CTLs after PMA/ionomycin-stimulation was not influenced significantly by IMQ. Thus, the biological activity of IMQ appears to exceed its previously known functions, inasmuch as it boosts up significantly the perforin-granule system.

Neurotransmitters regulate the migration and cytotoxicity in natural killer cells

Natural killer (NK) cells and cytotoxic T lymphocytes (CTL), the functional coordination of which are governed by various signal substances, are crucial in the body’s defense of tumor and virus-infected cells. We investigated the role of various neurotransmitters and hormones on the regulation of functional parameters, including NK cell cytotoxicity, and the migration of NK cells and CTL within a three-dimensional collagen lattice. Using peripheral blood CTL and NK cells, we show that the neurotransmitters endorphin, histamine and substance P increase NK cell cytotoxicity, while norepinephrine inhibits cytotoxicity. Moreover, substance P reduces migratory activity, while norepinephrine increases NK cell and CTL migration. Furthermore, all three steroid hormones which were investigated, namely cortisone, testosterone, and estradiol, had regulatory influence on both cytotoxicity and migration of NK cells. These results further specify the functional basis of the complex interconnection between the immune and neuro-endocrine systems.

Pre-infection frequencies of equine herpesvirus-1 specific, cytotoxic T lymphocytes correlate with protection against abortion following experimental infection of pregnant mares

In general, vaccines containing inactivated equine herpesvirus-1 (EHV-1) fail to prevent abortion in pregnant mares following infection with a virulent strain of EHV-1. We have tested the hypothesis that resistance to EHV-1-induced abortion in pregnant mares is associated with high frequencies of EHV-1 specific, major histocompatibility complex (MHC) class I-restricted, cytotoxic T lymphocytes (CTL) in the circulation. To test this theory, three groups of pregnant mares were assembled with varying backgrounds of infection or vaccination in an attempt to mimick the immune status of the general population. Group 1 mares ( n=9) were untreated controls selected at random. Group 2 mares ( n=5) were vaccinated three times intramuscularly with inactivated EHV-1. Group 3 mares ( n=3) had been infected with EHV-1 on four previous occasions. The frequency of CTL in blood leucocytes was measured by limiting dilution analysis at three time points; at the beginning of pregnancy (approximately 28 weeks before infection) in the Group 2 and Group 3 mares (4–7 weeks of gestation) (Group 1 was unavailable for sampling) and then 2 weeks before (30–40 weeks of gestation) and 3 weeks after experimental infection in all the mares. Serum samples were collected to monitor complement fixing (CF) antibody titres. Mares in all three groups were infected experimentally with EHV-1 strain Ab4/8 by the intranasal route after which they were monitored clinically to determine the outcome of pregnancy and samples were collected to determine the duration of nasopharyngeal shedding and cell-associated viraemia. The untreated control mares showed low pre-infection CTL. After experimental infection, they all seroconverted, aborted and demonstrated expected clinical and virological signs. Some vaccinated mares (3/5) had elevated titres of CF antibody prior to their first vaccination. All the vaccinated mares seroconverted after vaccination and exhibited higher CTL frequencies than controls before infection. Four of the five foaled normally. The multiply infected mares had low CF antibody titres prior to infection and showed neither seroconversion nor clinical or virological signs after infection. All multiply infected mares exhibited high frequencies of CTL before infection and they all foaled normally. The CTL frequencies observed differed significantly from the expected frequencies in the control and multiply infected groups at 2 weeks pre-infection ( P=0.034) and between the foaling and aborting mares at 2 weeks pre-infection ( P=0.005) and 3 weeks post-infection ( P=0.015). The results show a positive correlation between the number of virus-specific CTL in the peripheral blood of pregnant mares and their protection against abortion induced by EHV-1 infection. Therefore, as indicated by this study, rational approaches to the development of new vaccines for EHV-1 should stimulate cytotoxic immune responses and develop virus-specific CTL as pre-requisites for protection against abortion.

Pre-infection frequencies of equine herpesvirus-1 specific, cytotoxic T lymphocytes correlate with protection against abortion following experimental infection of pregnant mares

In general, vaccines containing inactivated equine herpesvirus-1 (EHV-1) fail to prevent abortion in pregnant mares following infection with a virulent strain of EHV-1. We have tested the hypothesis that resistance to EHV-1-induced abortion in pregnant mares is associated with high frequencies of EHV-1 specific, major histocompatibility complex (MHC) class I-restricted, cytotoxic T lymphocytes (CTL) in the circulation. To test this theory, three groups of pregnant mares were assembled with varying backgrounds of infection or vaccination in an attempt to mimick the immune status of the general population. Group 1 mares (n=9) were untreated controls selected at random. Group 2 mares (n=5) were vaccinated three times intramuscularly with inactivated EHV-1. Group 3 mares (n=3) had been infected with EHV-1 on four previous occasions. The frequency of CTL in blood leucocytes was measured by limiting dilution analysis at three time points; at the beginning of pregnancy (approximately 28 weeks before infection) in the Group 2 and Group 3 mares (4–7 weeks of gestation) (Group 1 was unavailable for sampling) and then 2 weeks before (30–40 weeks of gestation) and 3 weeks after experimental infection in all the mares. Serum samples were collected to monitor complement fixing (CF) antibody titres. Mares in all three groups were infected experimentally with EHV-1 strain Ab4/8 by the intranasal route after which they were monitored clinically to determine the outcome of pregnancy and samples were collected to determine the duration of nasopharyngeal shedding and cell-associated viraemia. The untreated control mares showed low pre-infection CTL. After experimental infection, they all seroconverted, aborted and demonstrated expected clinical and virological signs. Some vaccinated mares (3/5) had elevated titres of CF antibody prior to their first vaccination. All the vaccinated mares seroconverted after vaccination and exhibited higher CTL frequencies than controls before infection. Four of the five foaled normally. The multiply infected mares had low CF antibody titres prior to infection and showed neither seroconversion nor clinical or virological signs after infection. All multiply infected mares exhibited high frequencies of CTL before infection and they all foaled normally. The CTL frequencies observed differed significantly from the expected frequencies in the control and multiply infected groups at 2 weeks pre-infection (P=0.034) and between the foaling and aborting mares at 2 weeks pre-infection (P=0.005) and 3 weeks post-infection (P=0.015). The results show a positive correlation between the number of virus-specific CTL in the peripheral blood of pregnant mares and their protection against abortion induced by EHV-1 infection. Therefore, as indicated by this study, rational approaches to the development of new vaccines for EHV-1 should stimulate cytotoxic immune responses and develop virus-specific CTL as pre-requisites for protection against abortion.

Quantitative and functional analysis of PDC-E2–specific autoreactive cytotoxic T lymphocytes in primary biliary cirrhosis

While the pathologic mechanisms responsible for organ-specific tissue damage in primary biliary cirrhosis (PBC) remain an enigma, it has been suggested that the pathology is mediated by autoreactive T cells infiltrating the intrahepatic bile ducts. Previously, we have documented that there is 100-fold enrichment in the frequency of CD4+ autoreactive T cells in the liver that are specific for peptides encoded by the E2 components of the pyruvate dehydrogenase complexes (PDC-E2). We have also recently characterized the first MHC class I–restricted epitope for PDC-E2, namely amino acid 159–167, a region very similar to the epitope recognized by MHC class II–restricted CD4+ cells and by autoantibodies. The effector functions of these PDC-E2159-167–specific CD8+ cytotoxic T lymphocytes (CTLs) are not well understood. We have taken advantage of tetramer technology and report herein that there is tenfold increase in the frequency of PDC-E2159-167–specific CTLs in the liver as compared with the blood in PBC. In addition, the precursor frequency of the CTLs in blood was significantly higher in early-stage PBC. Of interest was the fact that, upon stimulation with the peptide, the response of PDC-E2159-167 tetramer-positive cells is heterogeneous with respect to IFN-γ synthesis. These data, we believe for the first time, document the enrichment of autoantigen-specific CD8+ T cells in the PBC liver, suggesting that CD8+ T cells play a significant role in the immunopathogenesis of PBC.