Cesira T. Bonanno

Reciprocal stimulation of γδ T cells and dendritic cells during the anti-mycobacterial immune response

γδ T cells and dendritic cells (DC) are two distinct cell types of innate immunity that participate in early phases of immune response against Mycobacterium tuberculosis infection. Here we show that a close functional relationship exists between these cell populations. Using an in vitro coculture system, Vγ1 T cells from Tcrb–/– mice were found to be activated by DC infected in vitro with BCG, as indicated by the elevated CD69 expression, IFN‐γ secretion and cytotoxic activity. This activation process was due to a non‐cognate mechanism since it required neither cell to cell contact nor interaction between the TCR and a specific antigen, but was mediated by DC‐derived IL‐12. Reciprocally, Vγ1 T cells provided a key cytokine, IFN‐γ, which increased IL‐12 production by BCG‐infected DC. Moreover, exposure of BCG‐infected DC to Vγ1 T cells conditioned the former to prime a significantly stronger anti‐mycobacterial CD8 T cell response. Consequently, stimulation of γδ T cells and their non‐cognate interaction with DC could be applied as an immune adjuvant strategy to optimize vaccine‐induced CD8 T cell immunity.

Aminobisphosphonate-activated gammadelta T cells in immunotherapy of cancer: doubts no more.

Background: Activated Vγ9Vδ2 T cells are able to kill most tumour cells because of recognition by T cell receptor and natural killer receptors. Objective: We discuss the possibility that the intentional activation of γδ T cells in vivo by aminobisphosphonates may represent a promising target for the design of novel and highly innovative immunotherapy in cancer patients. Methods: The antitumoural effects of γδ T cells both in vitro and in vivo have been demonstrated suggesting a new therapeutic approach for translation into the clinical setting. Results/conclusion: Vγ9Vδ2 T lymphocytes represent a particularly interesting target for immunotherapeutic protocols based on N-aminobisphosphonate administration and several Phase I-II trials are ongoing investigating the activity of zoledronic acid plus IL-2 in solid tumours.

The effect of cyclosporin A, FK506 and rapamycin on the murine contact sensitivity reaction

We have evaluated the effects of three potent immunosuppressive agents, cyclosporin A (CsA), FK506 and rapamycin, on the murine contact sensitivity (CS) reaction to the hapten trinitrochlorobenzene. Development of CS reaction requires participation of three distinct T cell subsets: αβ+, CD4+ T lymphocytes, which are the classical effector cell of the CS reaction, γδ+ T lymphocytes, and αβ+, double‐negative (CD4− CD8−) T lymphocytes that express the B220 molecule and produce IL‐4. We found that all three drugs inhibit the development of the CS reaction, but they affect different target cells. In fact, rapamycin and FK‐506 block both αβ+, CD4+ and γδ+ T lymphocytes, while CsA inhibits only the αβ+, CD4+ T lymphocyte. None of the three drugs exerted any inhibitory activity on the αβ+, double‐negative (CD4− CD8−) T lymphocytes. Hapten‐immune lymph node cells from mice treated in vivo with CsA or FK506 failed to proliferate and to produce IL‐2 when re‐exposed to the specific antigen in vitro. In contrast, immune lymph node cells from mice that had been treated in vivo with rapamycin gave optimal antigen‐specific proliferation and IL‐2 production in vitro. The implications of these observations are discussed in relation to the use of these immunosuppressive agents for prevention of allograft rejection.

HLA-A, -B and -DRB1 allele frequencies in Cyrenaica population (Libya) and genetic relationships with other populations.

The frequencies of HLA-A, HLA-B and HLA-DRB1 alleles in 118 unrelated Libyans from Benghazi (Cyrenaica) were analysed using high resolution typing and compared with other populations. Their relatedness has been tested by correspondence analyses and principal component analysis. The most frequent HLA-A alleles were A(∗)02:01:01:01 (15.7%), A(∗)01:01:01:01 (11.4%) and A(∗)03:01:01:01 (9.3%). For the HLA-B locus, the commonest allele was HLA-B(∗)50:01:01 (14.4%) followed by B(∗)51:01:01 (9.8%) and B(∗)08:01:01 (6.4%). For the HLA-DRB1 locus, the commonest was HLA-DRB1(∗)07:01:01:01 (16.9%) followed by DRB1(∗)03:01:01:01 (13.6%) and DRB1(∗)13:02:01 (9.3%). The most frequent two-locus haplotypes were HLA-A(∗)02:01:01:01-B(∗)07:02:01 (3.0%) and HLA-B(∗)50:01:01-DRB1(∗)07:01:01:01 (9.6%), and three-locus haplotypes were HLA-A(∗)02:01:01:01-B(∗)50:01:01-DRB1(∗)07:01:01:01 (4.2%) and HLA-A(∗)11:01:01-B(∗)52:01:01:01-DRB1(∗)15:02:01 (2.5%). This study is the first on the HLA status of a Libyan population. The results, when compared to similar HLA data obtained previously from African and Mediterranean populations, indicate genetic influences from several ethnic groups. Moreover, the differences in the HLA allele frequencies between the Libyan population and others reveals that significant admixture has occurred between the original Berber inhabitants and neighbouring and more distant populations, even though a strong genetic Berber substratum remains. These data will be of value to future anthropological and disease association studies involving the Libyan population.

Gluten Stimulation Induces an in vitro Expansion of Peripheral Blood Tγδ Cells from HLA-DQ2-Positive Subjects of Families of Patients with Celiac Disease

The intestinal gluten sensitivity formally known as celiac disease (CD) is characterized by an evident involvement of local immune response and it is associated with the expression of HLA-DQ2 allele. The major role in the disease seems to be played by the T lymphocyte population bearing γδ T cell receptor (Tγδ cells) which are increased both in peripheral blood and intestinal mucosae of celiac patients. In this paper data on the effects of in vitro gluten stimulation on lymphocytes expressing the Tγδ phenotype are reported. Gluten seems to be able to induce the expansion of the Tγδ cell population both in CD patients and their HLA-DQ2-positive asymptomatic relatives, in spite of the absence of clinical evidence of the disease. In addition, the evaluation of gluten-induced cytokine production shows that interleukin-4 could be implied in the early phases of pathogenesis of CD.

Impact of Human Leukocyte Antigen Polymorphisms in Human Immunodeficiency Virus Progression in a Paediatric Cohort Infected with a Mono-phyletic Human Immunodeficiency Virus-1 Strain

Objective: HLA polymorphisms within the peptide binding pocket have been associated with rapid and slowprogression to AIDS, suggesting that the capability to present efficiently HIV-1 epitopes is crucial for the infection control. To minimize the effects of genetic background due to population coming from different geographic area and viral strain variability in the cohort, an analysis of all the polymorphisms associated with the HLA-A, -B and -DR alleles has been performed in a cohort of children with a monophyletic HIV-1 infection (CRF02_AG) during an outbreak in Libya. Methods: High-resolution HLA-typing has been performed in 58 children infected with a monophyletic strain of HIV-1: 26 Long-Term Non-Progressors (LTNP), 9 Slow-Progressors (SP) and 23 Fast-Progressors (FP). HLA amino acid polymorphism frequency has been compared in the in FP respect to LTNP. Results: HLA-B resulted the most interesting locus of the study; 10 positions located in B- and F-pocket for peptidebinding have been found significant after Bonferroni’s correction: 11S (LTNP=7.69% FP=34.78% OR=0.156 P<0.05), 74D (LTNP=15.38%, FP=52.17%, OR=0.167; p<0.015) and 94T (LTNP=15.38%, FP=52.17%, OR=0.045; p<0.001), resulted associated with AIDS progression; 66N (LTNP=42.31% FP=8.7% OR=7.7; p<0.02), 80I (LTNP=80.77%, FP=34.78%, OR=7.86; p<0.036), 81A (LTNP=84.61%, FP=47.83%, OR=6; p<0.015), 82L (LTNP=88.46%, FP=47.83%, OR=7.86; p<0.006) and 83R (LTNP=88.46%, FP=47.83%, OR=7.86; p<0.006), has been associated with non-progression. Further, carrying Bw4-epitope resulted associated with LTNP (phenotype-frequency: LTNP=88.46%, FP=47.83%, OR=8.36; p<0.006), with homozygosis for Bw4 (LTNP=30.8%, FP=8.7%, p<0.05) associated with delayed progression and homozygosis for Bw6 (LTNP=11.5%, FP=52.1%, p<0.05) associated with fast progression to AIDS. Conclusion: The progression to AIDS might be in part determined by the binding capability of B-pocket and F-pocket of HLA-B and in part by the interaction of NK’s inhibitory receptor with HLA-B Bw4-epitope which regulate innate immune response and might have important implications for a better disease control.

Induction and tolerization of anti-male CD8+ cytotoxic T lymphocytes by in vivo immunization with an H-Y-derived peptide

We have analyzed the immune response induced by a 9mer synthetic peptide derived from the male histocompatibility antigen H-Y and containing Db-binding motifs in C57BL/6 mice. In this study we report that a single, subcutaneous injection of the peptide emulsified in IFA gave rise to the development of male-specific CD8+ T cells which displayed H-Y-specific proliferative response in vitro and showed a Tc1-type pattern of cytokine production (i.e. they secreted IFN-gamma and IL-2, but not IL-4 and IL-10). Development of a strong cytotoxic activity required in vitro stimulation with specific peptide and IL-2: under these culture conditions, we were able to generate potent CD8+ CTLs that lysed both male cells and peptide-pulsed female cells. Continuous administration of soluble peptide, delivered over a 7-day period by a mini-osmotic pump implanted subcutaneously, inhibited proliferative and cytotoxic responses and IFN-gamma production in lymph node cells from C57BL/6 mice subsequently primed with peptide in adjuvant. This decreased responses were associated with a strong increase in the secretion of IL-4 by antigen-specific CD8+ T lymphocytes. Subcutaneous administration of the H-Y-peptide in adjuvant significantly accelerates rejection of male skin graft, while continuous administration of peptide in soluble form did not modify the time course of rejection.

A Human Leucocyte Antigen‐DR1 Transgene Confers Susceptibility to Experimental Allergic Encephalomyelitis Elicited by an Epitope of Myelin Basic Protein

Much evidence now indicates that human leucocyte antigen (HLA) class I and class II transgenic (Tg) mice can be of value in analysing HLA‐restricted presentation of T‐cell epitopes relevant to experimental models of autoimmune diseases. One area where this has been applied is the characterization of myelin epitopes presented by HLA class II molecules in experimental model of multiple sclerosis (experimental allergic encephalomyelitis (EAE)). As a first step towards humanized disease models in HLA Tg mice, we have analysed immune response of lymph node cells of HLA‐DR1 Tg mice immunized with the human myelin basic protein (MBP) peptides 13–33, 87–106 and 139–154 bound by HLA‐DR1. We report here that HLA‐DR1 Tg mice display a hierarchy of response in vivo and in vitro to MBP epitopes depending on the binding affinity to DRB*0101 molecule. In fact, the 13–33 epitope induced a strong T helper 1 (Th1) response accompanied by high T‐cell precursor frequency and caused mild EAE, while the two other epitopes gave poor (139–154) or no disease (87–106), and these data correlate with in vitro Th1 response. These data could prove a useful tool in understanding the role played by different MBP epitopes in EAE.

HLA Class I and Class II Polymorphism in Three Sicilian Populations

ABSTRACT Two human leukocyte antigen (HLA) class I loci (HLA-A and HLA-B) and one class II locus (HLA-DR) were typed at the DNA level in the Sicilian population. Study participants were of Sicilian origin (183 for class I loci and 260 for class II loci) and live in three towns, chosen on the basis of geographic position and different historical events. These towns are Sciacca (southwest Sicily, located at sea level, conquered by Arabs in a.d. 814), Piana degli Albanesi (northwest Sicily, 720 m above sea level, has maintained religious, cultural, and linguistic peculiarities traced to Albanian settlement in 1488), and Troina (northeast Sicily, 1,120 m above sea level, known as the first settlement of Normans). The assumptions underlying the study of genetic structure, based on HLA allele polymorphism, are that these three towns are located in areas that can be distinguished according to historical criteria and that they are likely to have contributed to cultural and probably genetic differences. As such, the high frequency of some alleles in Sciacca and Troina seems to be correlated with Greek, Phoenician, North African, and Arab influence. In accordance with different human settlements in Sicily, we found that the HLA allele frequencies support the existence of genetic differentiation between the western and eastern sides of Sicily. This separation is attributed to Greek colonization in the east and to Phoenician-Carthaginian-Arab influence in the west. Moreover, the comparisons of all allele frequencies between Mediterranean and African populations show the same trend, highlighting in some cases European origin and in other cases non-European origin.