V Colizzi

University of Rome Tor Vergata, Roma, Latium, Italy

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Publications (143)460.83 Total impact

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    International Journal of Infectious Diseases 04/2014; 21. DOI:10.1016/j.ijid.2014.03.539 · 2.33 Impact Factor
  • International Journal of Infectious Diseases 04/2014; 21:145. DOI:10.1016/j.ijid.2014.03.726 · 2.33 Impact Factor
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    ABSTRACT: Objective: HLA polymorphisms within the peptide binding pocket have been associated with rapid and slow- progression 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 peptide- binding 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
    Journal of AIDS & Clinical Research 02/2014; DOI:10.4172/2155-6113.1000282 · 6.83 Impact Factor
  • Conference on AIDS Vaccine; 11/2013
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    ABSTRACT: As Cameroon scales up its national HIV/AIDS control program, evaluating the performance of commercially available tests for accurate and cost effective diagnostics becomes essential. A cross-sectional study assessed the performance of an HIV oral rapid test. A total of 1520 participants consented to participate in the study. After counselling, they were tested for HIV using the national algorithm followed by OraQuick. Results of the national algorithm were compared to those of OraQuick, for sensitivity, specificity, positive predictive and negative predictive values. 62% of participants were male, and 1% was reported HIV-positive following the national algorithm. The OraQuick test had 93% sensitivity, 99% specificity,99.93% NPV and 90% PPV (95% CI, Kappa 0.965). Though more expensive (2-6x) compared to the national algorithm tests, oral mucosal transudate-based test demonstrated good performance. Therefore, it could be implemented in resourceconstrained settings if subsidized and could increase participation since less invasive with no blood accident exposure.
    African Journal of Infectious Diseases 08/2013; 7(2). DOI:10.4314/ajid.v7i2.2
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    Retrovirology 09/2012; 9(2). DOI:10.1186/1742-4690-9-S2-P239 · 4.77 Impact Factor
  • Journal of Hepatology 04/2012; 56:S66. DOI:10.1016/S0168-8278(12)60165-2 · 10.40 Impact Factor
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    ABSTRACT: Most commercial HIV-1 genotyping assays are hampered by high cost in resource-limited settings. Moreover, their performance might be influenced over time by HIV genetic heterogeneity and evolution. An in-house genotyping protocol was developed, and its sequencing performance and reproducibility were compared to that of ViroSeq™. One hundred ninety plasma samples from HIV-1-infected subjects in Cameroon, a resource-limited setting with a high HIV genetic variability, were processed for pol gene sequencing with an in-house protocol, ViroSeq™, or both. Only non-B subtypes were found. The in-house sequencing performance was 98.7% against 92.1% with ViroSeq™. Among 36 sequence pairs obtained using both assays, the overall rate of discordant amino acid positions was negligible (0.24%). With its high sensitivity and reproducibility, as well as its affordable cost (about half of ViroSeq™: 92 € vs. 217 €), this in-house assay is a suitable alternative for HIV-1 genotyping in resource-limited and/or in high-genetic-diversity settings.
    Archives of Virology 07/2011; 156(7):1235-1243. DOI:10.1007/s00705-011-0982-3 · 2.28 Impact Factor
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    ABSTRACT: Vγ9Vδ2 T lymphocytes have been shown to respond to a variety of non-peptide antigens including alkylamines and phosphoantigens. Recently, aminobisphosphonates have also been shown to stimulate this subset of γδ+ T cells. In this study we analyzed the proliferative responses of freshly isolated γδ T lymphocytes obtained from human cord blood when challenged with pyrophosphomonoesters or aminobisphosphonates. Nitrogen-containing aminobisphopsphonates, in contrast to phoshoantigens, readily stimulated expansion of Vδ2Vγ9 cells in human cord blood. Expanded cells displayed an activated mature phenotype, and were capable of producing TNFalpha and IFNgamma but not perforin following secondary stimulation, consistent with the development of a regulatory, as opposed to cytotoxic, phenotype. This approach may provide a useful strategy for a new approach to the treatment of neonatal pathologies.
    International journal of immunopathology and pharmacology 01/2011; 24(1):101-10. · 2.51 Impact Factor
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    ABSTRACT: The cytotoxic and anti-Mycobacterium tuberculosis H37Rv activities of hydro-alcoholic extract of Lannea acida A. Rich (Anacardiaceae) were assessed. The cytoxicity evaluation was carried out on THP1 monocytoid cell line (after 24 h at 1; 5 and 10 μg mL<SUP>-1</SUP>) and showed only a slight modification of lactate dehydrogenase (LDH) release. The rate of monocytes in different stages of mitosis had been amended in absence and presence of extract as follows: Go/ G1 58.83 - 59.83%; synthesis 21.95 - 18.64%; mitosis 16.67 - 15.77%; necrosis 2.65 - 5.64 %. The percentage of inhibition of Mycobacterium tuberculosis proliferation was respectively 77.6 and 36.8% at 1.2 and 0.6 mg mL<SUP>-1</SUP> of extract. This is an interesting experimental study on antimicrobial and immune-stimulating properties of Lannea acida ethanol-water (70%v/v) extract which may contain potential antibacterial and immune-stimulating agents for clinical use.
    Pakistan Journal of Biological Sciences 01/2011; DOI:10.3923/pjbs.2011.47.52
  • International Journal of Infectious Diseases 03/2010; 14. DOI:10.1016/j.ijid.2010.02.407 · 2.33 Impact Factor
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    ABSTRACT: Two sample panels: 1) 20 pulmonary tuberculosis (PTB) patients and 10 healthy subjects from a country with a low incidence of TB (Italy); and 2) 47 PTB patients and 26 healthy subjects from a country with a high incidence of TB (Morocco). To identify a combination of Mycobacterium tuberculosis peptides useful for the serodiagnosis of active PTB. Fifty-seven B-cell epitope peptides of M. tuberculosis were evaluated by immunoenzymatic assay and the data were analysed using logistic regression analysis and the random forest method. The best discriminating peptide between PTB patients and healthy subjects from the sample of the low TB incidence country was the 23 amino acid peptide of the Rv3878 protein. The sensitivity and specificity were respectively 65% and 100%. The same peptide had a sensitivity and specificity of respectively 47% and 100% for the sample from the high TB incidence country. The best combination of peptides was a pool of nine peptides which had a sensitivity of 70.2% and a specificity of 100% in the high TB incidence country. The 9-peptide pool can be useful in identifying patients with active PTB.
    The International Journal of Tuberculosis and Lung Disease 08/2009; 13(7):848-54. · 2.76 Impact Factor
  • Tuberculosis 01/2009; · 3.50 Impact Factor
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    ABSTRACT: The present research was aimed to prevent mother-to-child transmission of HIV; to use RT-PCR in order to detect, 6 months after birth, infected children; and to test the antiretroviral resistance of both children and mothers in order to offer them a suitable therapy. At the Saint Camille Medical Centre, 3,127 pregnant women (aged 15–44 years) accepted to be enrolled in the mother-to-child transmission prevention proto-col that envisages: (i) Voluntary Counselling and Testing for all the pregnant women; (ii) Antire-troviral therapy for HIV positive pregnant women and for their newborns; (iii) either powdered milk feeding or short breast-feeding and RT-PCR test for their children; (iv) finally, pol gene sequencing and antiretroviral resistance identifications among HIV positive mothers and children. Among the patients, 227/3,127 HIV seropositive women were found: 221/227 HIV-1, 4/227 HIV-2, and 2/227 mixed HIV infections. The RT-PCR test allowed the detection of 3/213 (1.4%) HIV infected children: 0/109 (0%) from mothers under ARV therapy and 3/104 (2.8%) from mothers treated with Nevirapine. All children had recombinant HIV-1 strain (CRF06_CPX) with: minor PR muta-tions (M36I, K20I) and RT mutations (R211K). Among them, two twins had Non-Nucleoside Reverse Transcriptase Inhibitor mutation (Y18CY). Both mothers acquired a major PR mutation (V8IV), investigated 6 months after a single-dose of Nevirapine. Prevention by single-dose of Nevirapine reduced significantly mother-to-child transmission of HIV, but caused many mutations and resistance to antiretroviral drugs. Based on present study the antiretroviral therapy protocol, together with the artificial-feeding, might represent the ideal strategy to avoid transmission of HIV from mother-to-child.
    Journal of Medical Virology 07/2007; 79(79):873-879873. DOI:10.1002/jmv.20913 · 2.22 Impact Factor
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    ABSTRACT: Sphingosine 1-phosphate (S1P) is a lipidic messenger known to exert several physiological functions within the cell. We tested here whether the stimulation of human monocytes with different doses of S1P might interfere with their differentiation into competent dendritic cells (DC). Monocytes cultured with granulocyte macrophage colony stimulating factor, interleukin-4 (IL-4) and S1P differentiated into a DC population lacking CD1a molecules on the surface and acquired some aspects of mature DC (mDC), though in the absence of maturation stimuli. When stimulated with lipopolisaccharide (LPS), CD1a(-) DC produce high amounts of tumour necrosis factor-alpha and IL-10, but not IL-12. Accordingly, these CD1a(-) DC were not capable of stimulating allogenic T lymphocytes so well as CD1a(+) DC generated from untreated monocytes and maturated with LPS. S1P monocyte-derived DC lost their polarizing capacity abrogating the production of gamma-interferon/IL-4 by co-cultured naïve CD4(+)CD45RA(+) T cells. Our findings suggest a mechanism through which S1P can favour the development of immune-related pathological states.
    Scandinavian Journal of Immunology 02/2007; 65(1):84-91. DOI:10.1111/j.1365-3083.2006.01860.x · 1.88 Impact Factor
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    ABSTRACT: Non-B HIV subtypes have been estimated to account for 88% of HIV infections in the world. These subtypes are particularly relevant in view of the availability of antiretroviral (ARV) drugs, since subtype-specific mutations are associated with drug-resistance in developing countries. Therefore, the pol gene sequences in HIV-1 isolates were examined from the three distinct groups of 39 infected patients from Ouagadougou in Burkina Faso: 17 patients who had not received any antiretroviral therapy (ART); 16 patients received ART, and 6 HIV-infected children, from infected mothers, received a single Nevirapine dose prophylaxis during birth. HIV-1 pol sequencing was successful for 29 samples. As expected, all patients presented the common (non-B subtype) M36I polymorphism and 26/29 (90%) the K20I mutation. Phylogenetic studies showed high predominance of recombinant HIV-1 strains: CRF06_cpx 16/29 (55.17%), CRF02_AG 9/29 (31.03%), A1 2/29 (6.89%), G 1/29 (3.44%), and CRF09_cpx 1/29 (3.44%). Two twins showed, 6 months after birth, a NNRTI-mutation (Y181C/Y). During the same period, the twin mother presented a different NNRTI-mutation (V106I), thus suggesting that the different blood drug concentration may determine a different drug-resistance pathway. Among 17 non-highly active antiretroviral therapy (HAART) patients, 3/17 (17.64%) presented virus with reverse transcriptase (RT) mutations [V118I: 1/17 patients (5.88%), V179E: 2/17 patients (11.76%)]. 10/17 (58.82%) presented virus with minor protease (PR) mutations [L63P: 5/17 patients (29.41%), V77I: 3/17 patients (17.64%), L10I: 2/17 patients (11.76%)]. 4/17 patients did not show any PR and RT mutations (23.52%). Among six HAART-treated patients, 6/6 and 3/6 had M36I and L63LP protease minor subtypes, respectively; and only two (33.33%) presented virus with K103N mutation. The low prevalence of drug-resistant associated mutations in Burkina Faso is encouraging. However, further studies with a larger cohort with a high non-B subtype prevalence are necessary to optimize ART in developing countries.
    Journal of Medical Virology 11/2006; 78(11):1385-91. DOI:10.1002/jmv.20709 · 2.22 Impact Factor
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    ABSTRACT: Apoptosis is a physiological programmed cell death process whose dysregulation plays an important role in different human infectious diseases. An increasing number of intracellular pathogens are known to induce target cell apoptosis, while some other parasites inhibit it. Unlike necrosis, apoptosis is a silent immunological event occurring without inflammation. Infection-induced target cell apoptosis may be a successful strategy to eliminate pathogens and assure host survival. Conversely, apoptosis inhibition could represent an adaptive mechanism for pathogen survival, while it may be beneficial for the host to initiate an effective immune response. The worldwide increase in tuberculosis has stimulated more research aimed at defining the interaction between Mycobacterium tuberculosis and the immune system. M. tuberculosis possesses sophisticated strategies to circumvent its fate within target monocytic cells. Apoptosis of alveolar macrophages and monocytes has been described as a consequence of M. tuberculosis infection. Moreover, the observation that mycobacterial lipoproteins activate macrophages through Toll-like receptor (TLR) 2 suggests that innate immune receptors contribute to defence against M. tuberculosis. There is evidence that TLR-induced apoptosis modulates inflammation and immune activation during M. tuberculosis infection. Finally, the role of apoptotic-infected cells as a source of microbial antigens for cross-priming of effector T-cells is also discussed.
    The International Journal of Tuberculosis and Lung Disease 05/2005; 9(4):375-83. · 2.76 Impact Factor
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    ABSTRACT: Nonsyncytium inducing, macrophage tropic HIV strains predominate in the course of active tuberculosis (TB). The present study assesses the expression of CCR5 in CD4+ T-lymphocytes from blood and bronchoalveolar lavage (BAL) of TB patients, non-TB lung disease controls and healthy controls. Memory (CD45RO+), recently activated (CD69+), proliferating (Ki67+) CCR5+ or CCR3+ CD4+ T-lymphocytes were determined by multiparametric flow cytometry analysis. Results show that BAL CD4+ T-lymphocytes expressing CCR5 or CCR3 were significantly increased when compared to peripheral blood both in patients and in healthy controls. However, the data show that the proportions of peripheral blood CCR5+ CD4+ and CCR3+ CD4+ T-lymphocytes and BAL CCR5+ CD4+ T-lymphocytes, but not BAL CCR3+ CD4+ T-lymphocytes, were significantly increased in TB patients. Furthermore, the observation that BAL CCR5+ CD4+ T-lymphocytes from TB patients expressed early activation markers, were not proliferating and showed down-regulation of CCR5 expression suggests recruitment and trapping at the site of disease. Altogether, these results suggest that the lower respiratory tract mucosa may provide cellular targets accessible for efficient transmission of macrophage tropic HIV-1 variants and that tuberculosis may enhance this phenomenon.
    European Respiratory Journal 11/2004; 24(4):638-43. DOI:10.1183/09031936.04.000105403 · 7.13 Impact Factor
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    ABSTRACT: The polymorphism at position beta69 of the human leukocyte antigen (HLA)-DP molecule has been associated with susceptibility to several immune disorders and alloreactivity. Using molecular modeling, we have predicted a detailed structure of the HLA-DP2 molecule (carrying Glubeta69) complexed with class II associated invariant chain derived peptide (CLIP) and compared it with the form carrying Lys at beta69 (HLA-DP2K69). Major changes between the two models were observed in the shape and charge distribution of pocket 4 and of the nearby pocket 6. Consequently, we analyzed in detail the peptide-binding specificities of both HLA-DP molecules expressed as recombinant proteins. We first determined that the minimum peptide-binding core of CLIP for both HLA-DP2 and DP2K69 is represented by nine aminoacids corresponding to the sequence 91-99 of invariant chain (Ii). We then assessed the peptide-binding specificities of the two pockets and determined the role of position beta69, using competition tests with the Ii-derived peptide CLIP and its mutated forms carrying all the aminoacidic substitutions in P4 and P6. Pocket 4 of HLA-DP2 showed high affinity for positively charged, aromatic, and polar residues, whereas aliphatic residues were disfavored. Pocket 4 of the DP2K69 variant showed a reduced aminoacid selectivity with aromatic residues most preferred. Pocket 6 of HLA-DP2 showed high affinity for aromatic residues, which was increased in DP2K69 and extended to arginine. Finally, we used the experimental data to determine the best molecular-modeling approach for assessing aminoacid selectivity of the two pockets. The results with best predictive value were obtained when single aminoacids were evaluated inside each single pocket, thus, reducing the influence of the overall peptide/ major histocompatibility complex interaction. In conclusion, the HLA-DPbeta69 polymorphism plays a fundamental role in the peptide-binding selectivity of HLA-DP. Furthermore, as this polymorphism is the main change in the pocket 4 area of HLA-DP, it could represent a supertype among HLA-DP molecules significantly contributing to the selection of epitopes presented in the context of this HLA isotype.
    Tissue Antigens 01/2004; 62(6):459-71. DOI:10.1046/j.1399-0039.2003.00131.x · 2.35 Impact Factor
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    ABSTRACT: The present study addresses the differential ability of macrophages to control intracellular growth of non-pathogenic Mycobacterium smegmatis (Msm) and pathogenic M. tuberculosis (MTB). Results reported herein show that 3 h post infection, intracellular Msm, but not MTB, was significantly killed by macrophages. As the role of human macrophage phospholipase D (PLD) in the activation of antimicrobial mechanisms has been documented, we hypothesised the role of such enzyme in antimycobacterial mechanisms. To this aim, macrophage PLD activity was analysed at different times after exposure with either pathogenic MTB or non-pathogenic Msm. Results showed that, starting from 15 min after mycobacterial exposure, MTB did not induce macrophage PLD activity, whereas the environmental non-pathogenic Msm stably increased it. The direct contribution of PLD in intracellular mycobacterial killing was also analysed by inhibiting enzymatic activity with ethanol or calphostin C. Results show that PLD inhibition significantly increases intracellular Msm replication. In order to see whether the innate PLD-mediated antimicrobial mechanisms against MTB are also induced after CpG ODN stimulation, the role of PLD has been analysed in the course of CpG-mediated intracellular MTB killing. CpG DNA increased PLD activity in both uninfected and MTB-infected macrophages, and the inhibition of PLD activity resulted in a significant reduction of CpG-induced MTB killing. Taken together, our data suggest a relationship between host PLD activation and the macrophage ability to control intracellular mycobacterial growth.
    Cellular Microbiology 01/2004; 5(12):913-20. DOI:10.1046/j.1462-5822.2003.00330.x · 4.82 Impact Factor

Publication Stats

2k Citations
460.83 Total Impact Points


  • 1991–2014
    • University of Rome Tor Vergata
      • Dipartimento di Biologia
      Roma, Latium, Italy
  • 2011
    • Chantal BIYA International Reference Centre for Research on HIV/AIDS Prevention and Management
      Jaúnde, Centre Region, Cameroon
  • 2009
    • Institut National d'Hygiène du Maroc
      Rabat, Rabat-Salé-Zemmour-Zaër, Morocco
  • 2003
    • The Institute for Molecular Medicine
      Huntington Beach, California, United States
  • 2001
    • National Institute of Allergy and Infectious Diseases
      Maryland, United States
  • 1987–2000
    • Sapienza University of Rome
      Roma, Latium, Italy
  • 1999
    • Italian National Research Council
      • Institute of Neurobiology and Molecular Medicine INMM
      Roma, Latium, Italy
  • 1998
    • University of Wisconsin, Madison
      • Department of Medical Microbiology and Immunology
      Madison, MS, United States
  • 1996
    • Institut Pasteur
      Lutetia Parisorum, Île-de-France, France
  • 1995
    • Jagiellonian University
      Cracovia, Lesser Poland Voivodeship, Poland
  • 1994
    • Università degli Studi Europea di Roma
      Roma, Latium, Italy
  • 1979–1988
    • Università di Pisa
      • Department of Biology
      Pisa, Tuscany, Italy
  • 1985
    • Università degli studi di Palermo
      • Department of internal medicine and medical specialties (DIMIS)
      Palermo, Sicily, Italy
  • 1984
    • Harvard Medical School
      • Department of Pathology
      Boston, Massachusetts, United States