111 results on '"Vasanthapuram, Ravi"'
Search Results
102. Cytotoxic T lymphocytes raised against Japanese encephalitis virus: effector cell phenotype, target specificity and in vitro virus clearance
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Ramanathapuram Manjunath, Vasanthapuram Ravi, and Kaja Murali-Krishna
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Cytotoxicity, Immunologic ,viruses ,Genes, MHC Class I ,chemical and pharmacologic phenomena ,Virus Replication ,Biochemistry ,Virus ,Cell Line ,Mice ,Immune system ,Antigen ,Virology ,Tumor Cells, Cultured ,Cytotoxic T cell ,Animals ,Antigens, Ly ,Encephalitis Virus, Japanese ,Mice, Inbred BALB C ,biology ,H-2 Antigens ,Antibodies, Monoclonal ,T lymphocyte ,biology.organism_classification ,Cytotoxicity Tests, Immunologic ,In vitro ,Flavivirus ,Cell culture ,West Nile virus ,Spleen ,T-Lymphocytes, Cytotoxic - Abstract
Several H-2 defined cell lines were examined for their ability to support infection and replication of Japanese encephalitis virus (JEV) before their use in in vitro and in vivo stimulation protocols for generating cytotoxic T lymphocytes (CTLs) against JEV. Among II different cell lines tested, two H-2(d) macrophage tumour lines (P388D1, RAW 264.7), an H-2(d) hybridoma (Sp2/0), an H-2K(k)D(d) neuroblastoma (Neuro 2a), and H-2(k) fibroblast cell line (L929) were found to support JEV infection and replication. These cell lines were used to generate anti-JEV CTLs by using in vivo immunization followed by in vitro stimulation of BALB/c mice. We observed that not only syngeneic and allogeneic infected cells but also JEV-infected xenogeneic cells could prime BALB/c mice for the generation of JEV-specific CTLs upon subsequent in vitro stimulation of splenocytes with JEV-infected syngeneic cells. Although infected xenogeneic cells were used for immunization, the anti-JEV effecters that were generated lysed infected syngeneic targets but not JEV-infected xenogeneic or allogeneic target cells in a 5h Cr-51 release assay. These anti-JEV effecters recognized syngeneic target cells infected with West Nile virus to a lesser extent and were shown to be Lyt-2.2(+) T cells. The results of unlabelled cold target competition studies suggested alterations in the cell surface expression of viral antigenic determinants recognized by these CTLs. We further demonstrate that the JEV-specific CTLs generated could virtually block the release of infectious virus particles from infected P388D1 and Neuro 2a cells in vitro.
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- 1994
103. Evaluation of Three Commercially Available Japanese Encephalitis Virus IgM Enzyme-Linked Immunosorbent Assays
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Robinson, Jaimie S., primary, Biggerstaff, Brad J., additional, Ramamurty, Nalini, additional, Johnson, Barbara W., additional, Sandhu, Hardeep S., additional, Chowdhury, Anwarul Haque, additional, Cavallaro, Kathleen F., additional, Vasanthapuram, Ravi, additional, Desai, Anita, additional, and Featherstone, David, additional
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- 2010
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104. N-methylisatin-beta-thiosemicarbazone derivative (SCH 16) is an inhibitor of Japanese encephalitis virus infection in vitro and in vivo
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Sebastian, Liba, primary, Desai, Anita, additional, Shampur, Madhusudana N, additional, Perumal, Yogeeswari, additional, Sriram, D, additional, and Vasanthapuram, Ravi, additional
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- 2008
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105. Gene Expression Analysis from Human Immunodeficiency Virus Type 1 Subtype C Promoter and Construction of Bicistronic Reporter Vectors.
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Nagadenahalli Byrareddy Siddappa, Venkatesh Prasanna Kashi, Mohanram Venkatramanan, Anangi Balasiddaiah, Narayana Jayasuryan, Anita Mahadevan, Anita Desai, Kadappa S. Satish, Susarla K. Shankar, Vasanthapuram Ravi, and Udaykumar Ranga
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We report the cloning and sequence analysis of the long terminal repeat (LTR) of several primary HIV-1 subtype C strains of India. Phylogenetically, all the LTRs and the paired env sequences clustered with subtype C reference strains. The LTRs demonstrated extensive polymorphism in the transcription factor binding sites (TFBS) within the enhancer and the modulator regions. We generated reporter vectors under the control of a select subset of the subtype C LTRs. The reporter vectors are distinguished by the simultaneous expression of two independent reporter genes, secreted alkaline phosphatase (SEAP) and enhanced green fluorescence protein (EGFP), in response to Tat. Expression of EGFP was facilitated by engineering an internal ribosome entry site (IRES) into the expression cassette. Although subtype C strains cause a large majority of the global infections, and important differences in the transcription factor binding sites have been identified in the subtype C promoter, few reporter vectors containing subtype C-LTR have been described. We analyzed gene expression from the C-LTR reporter vectors in different cell lines under diverse experimental conditions and compared it to the B-LTR reporter vector. The reporter vectors were responsive to Tat derived from diverse viral subtypes. Furthermore, a positive correlation was observed between the expression of the reporter genes and the viral structural protein p24 when the cells were infected with viral molecular clones. The LTR reporters we developed could be of significant use in the study of viral transactivation, in the evaluation of biological properties of viral subtypes, and in the screening for antiviral inhibitors. [ABSTRACT FROM AUTHOR]
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- 2007
106. Development and evaluation of a competitive ELISA for estimation of rabies neutralizing antibodies after post-exposure rabies vaccination in humans
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Kader Muhamuda, Vasanthapuram Ravi, and Shampur Narayan Madhusudana
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Microbiology (medical) ,medicine.drug_class ,Rabies ,Fluorescent Antibody Technique ,Enzyme-Linked Immunosorbent Assay ,Monoclonal antibody ,Antibodies, Viral ,Sensitivity and Specificity ,Virus ,Neutralization ,C-ELISA ,Mice ,Neutralization Tests ,medicine ,Animals ,Humans ,Post-exposure vaccination ,biology ,business.industry ,Antibody titer ,General Medicine ,medicine.disease ,Virology ,Vaccination ,Titer ,Infectious Diseases ,Rabies Vaccines ,Immunology ,biology.protein ,Antibody ,business - Abstract
SummaryObjectivesCurrently three tests are approved for the estimation of neutralizing antibodies after rabies vaccination: the mouse neutralization test (MNT), the rapid fluorescent focus inhibition test (RFFIT), and the fluorescent antibody virus neutralization (FAVN) test. Performance of these tests requires a lot of expertise and is generally carried out in reference laboratories and, hence, they are not available to many people. The aim of the present study was to develop and evaluate a competitive ELISA (C-ELISA) for estimation of neutralizing antibodies in order to make this testing more widely available.MethodsThe C-ELISA was designed based on competition between a murine neutralizing monoclonal antibody (Mab) and the antibodies in serum of vaccinated people. The test was initially standardized using known negative and known positive serum samples for determining the optimal dilution of the Mab as well as the cut-off value (%) for ascertaining the level of inhibition. Nine hundred and ninety serum samples were tested from 250 people who had been administered purified chick embryo cell vaccine (PCECV). Serum samples were collected on days 0, 14, 30 and 90 post-vaccination, and were tested by C-ELISA.ResultsAll the serum samples that were positive by RFFIT were also positive by C-ELISA. The titers obtained with C-ELISA were marginally higher than the RFFIT titers, but a significant correlation was noted between the two tests (r=0.897). None of the negative controls were detected to be positive for rabies antibodies by either of these tests. Therefore the C-ELISA was found to be 100% specific and sensitive in comparison to RFFIT. Further, the initial rise and fall of antibody titers on different days post-vaccination was comparable for both tests.ConclusionsThe C-ELISA described herein can be used to quantify rabies neutralizing antibody levels after vaccination. This test is simple and can be conveniently used under field conditions for monitoring seroconversion after post-exposure rabies vaccination. Moreover it does not require handling of infectious virus by the end user.
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107. Laboratory diagnosis of japanese encephalitis using monoclonal antibodies and correlation of findings with the outcome
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Vasanthapuram Ravi, S. Vanajakshi, Anke Gowda, and A. Chandramuki
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Adolescent ,medicine.drug_class ,viruses ,Antibodies, Viral ,Monoclonal antibody ,Virus ,Mice ,Cerebrospinal fluid ,Antigen ,Virology ,medicine ,Animals ,Humans ,Child ,Encephalitis, Japanese ,Antigens, Viral ,Encephalitis Virus, Japanese ,biology ,Antibodies, Monoclonal ,Infant ,Japanese encephalitis ,medicine.disease ,biology.organism_classification ,Flavivirus ,Infectious Diseases ,Immunoglobulin M ,Child, Preschool ,Immunoglobulin G ,Immunology ,biology.protein ,Viral disease ,Antibody - Abstract
Detection of virus, viral antigen, and class-specific antibody was carried out in cerebrospinal fluid (CSF) and sera of 27 children with Japanese encephalitis. The diagnosis could be confirmed in 78.57% of cases (22/27) by demonstration of virus-specific IgM in CSF (15/22), viral antigen in CSF (5/22), or by virus isolation (2/22). Absence of virus specific IgM in CSF was associated with a fatal outcome (P = 0.05).
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- 1989
108. Correlation of tumor necrosis factor levels in the serum and cerebrospinal fluid with clinical outcome in Japanese encephalitis patients
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Vasanthapuram Ravi, Shreemanta K. Parida, Georges E. Grau, Mandaville Gourie-Devi, A. Chandramuki, and Anita Desai
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Necrosis ,biology ,business.industry ,medicine.medical_treatment ,Japanese encephalitis ,medicine.disease ,biology.organism_classification ,Virology ,Central nervous system disease ,Flaviviridae ,Infectious Diseases ,Cytokine ,Cerebrospinal fluid ,biology.protein ,medicine ,Tumor necrosis factor alpha ,Antibody ,medicine.symptom ,business - Abstract
To investigate the prognostic role of tumour necrosis factor (TNF) in Japanese encephalitis virus (JEV) infection, we measured the immunoreactive forms of TNF concentrations in the serum and cerebrospinal fluid (CSF) of 47 laboratory-confirmed cases of JE. It was observed that TNF levels were elevated (>15 pgm/ml) in all the 47 serum samples (range 19.4–923.8 pg/ml), while in 46/47 CSF samples TNF was elevated (range 10.8–376 pg/ml). The mean (SD) TNF levels in the serum of fatal cases was 234.34 pg/ml (304.40) as compared to the mean of 85.31 pg/ml (SD 153.92) in nonfatal cases. Similar observations were also made with respect to the TNF levels in the CSF; the mean of fatal cases was 69.39 pg/ml (SD 39.00) in contrast to the mean of 62.41 pg/ml (SD 75.25) of nonfatal cases. The increase in TNF levels did not show any correlation to the duration of illness. It was further observed that the mortality rate increased with increasing concentrations of TNF in the serum and CSF. Correlation of laboratory parameters to final outcome revealed that TNF concentrations above 50 pg/ml in serum correlated significantly (P = .05) with a fatal outcome, whilst high levels of JEV-IgM antibodies (>500 units) in the CSF correlated with a nonfatal outcome (P = .03). These results suggest that TNF can be used as a possible prognosticator of a fatal outcome in JEV infection. J Med Virol 51:132–136, 1997. © 1997 Wiley-Liss, Inc.
109. Identification of unique B/C recombinant strains of HIV-1 in the southern state of Karnataka, India
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Narayana Jayasuryan, Udaykumar Ranga, Nagadenahalli B. Siddappa, Prashanta Kumar Dash, Anita Mahadevan, Parthasarathy Satishchandra, Vasanthapuram Ravi, Susarla K. Shankar, and Anita Desai
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Adult ,Male ,Adolescent ,Immunology ,Human immunodeficiency virus (HIV) ,India ,HIV Infections ,Biology ,medicine.disease_cause ,Virus ,law.invention ,law ,medicine ,Immunology and Allergy ,Humans ,Phylogeny ,Recombination, Genetic ,Middle Aged ,biology.organism_classification ,Virology ,Infectious Diseases ,Lentivirus ,Recombinant DNA ,HIV-1 ,Female ,Viral disease - Abstract
We characterized the molecular nature of a large number of primary HIV-1 isolates in the four southern states of India. In addition to confirming a predominance of subtype C infection, for the first time we identified three B/C recombinant viruses in a subset of 115 samples. Unexpectedly, env sequences of two of the three B/C recombinants phylogenetically clustered with subtype B strains of the USA. The determination of the real incidence of the recombinant viruses is of importance.
110. Does the HIV virus piggy back into the brain within inflammatory cells following opportunistic infections?
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Mahadevan, A., Shankar, Susarla K., Satishchandra, Parthasarathy, Siddappa, N. B., Ranga, Udaykumar, Chickabasaviah, Yasha Thagadur, Santosh, Vani, Vasanthapuram, Ravi, and Nath, Avindra
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HIV ,BRAIN diseases ,OPPORTUNISTIC infections ,ANTIVIRAL agents ,AIDS dementia complex - Abstract
Background: HIV-Clade C is the commonest subtype in Africa and Asia, but it remains unknown if this clade can invade the brain and cause neuronal damage. CNS opportunistic infections (OI) are common and frequently cause death. It remains unknown if OI can serve as a portal of HIV entry into the brain, putting patients at risk of developing HIV encephalitis and dementia. Methods: Formalin fixed tissues from 15 patients (toxoplasma encephalitis=5, tuberculous meningitis-5 and cryptococcal meningitis-5, head injury without OI-3) who came to autopsy at NIMHANS, Bangalore were immunostained for HIV-p24, CD68 and GFAP. All died within 6 months of onset of neurological symptoms and did not receive antiretroviral therapy. Results: Cerebral toxoplasmosis had the largest largest load of HIV infected cells around the foci of toxoplasma encephalitis. In tuberculosis, the HIV infected cells were prominent in the meningeal infiltrate with focal infiltration into the superficial cortex in few cases. Patients with cryptococcal meningitis had the least amount of inflammatory infiltrates restricted to meninges. HIV infected cells were occasionally present in the choroid plexus, suggesting that this could be a portal of entry for these cells into the sub-arachanoid space. Conclusions: The finding of large amounts of viral antigen within the brain in conjunction with various OI suggests that HIV dementia may supervene once the OI is successful treated. On the other hand, effective treatment of OI may inhibit OI induced pathology and help limit viral burden. This will have important public health implications in addressing the HIV epidemic in developing countries [ABSTRACT FROM AUTHOR]
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- 2007
111. Tracking the international spread of SARS-CoV-2 lineages B.1.1.7 and B.1.351/501Y-V2 with grinch.
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O'Toole Á, Hill V, Pybus OG, Watts A, Bogoch II, Khan K, Messina JP, Tegally H, Lessells RR, Giandhari J, Pillay S, Tumedi KA, Nyepetsi G, Kebabonye M, Matsheka M, Mine M, Tokajian S, Hassan H, Salloum T, Merhi G, Koweyes J, Geoghegan JL, de Ligt J, Ren X, Storey M, Freed NE, Pattabiraman C, Prasad P, Desai AS, Vasanthapuram R, Schulz TF, Steinbrück L, Stadler T, Parisi A, Bianco A, García de Viedma D, Buenestado-Serrano S, Borges V, Isidro J, Duarte S, Gomes JP, Zuckerman NS, Mandelboim M, Mor O, Seemann T, Arnott A, Draper J, Gall M, Rawlinson W, Deveson I, Schlebusch S, McMahon J, Leong L, Lim CK, Chironna M, Loconsole D, Bal A, Josset L, Holmes E, St George K, Lasek-Nesselquist E, Sikkema RS, Oude Munnink B, Koopmans M, Brytting M, Sudha Rani V, Pavani S, Smura T, Heim A, Kurkela S, Umair M, Salman M, Bartolini B, Rueca M, Drosten C, Wolff T, Silander O, Eggink D, Reusken C, Vennema H, Park A, Carrington C, Sahadeo N, Carr M, Gonzalez G, de Oliveira T, Faria N, Rambaut A, and Kraemer MUG
- Abstract
Late in 2020, two genetically-distinct clusters of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with mutations of biological concern were reported, one in the United Kingdom and one in South Africa. Using a combination of data from routine surveillance, genomic sequencing and international travel we track the international dispersal of lineages B.1.1.7 and B.1.351 (variant 501Y-V2). We account for potential biases in genomic surveillance efforts by including passenger volumes from location of where the lineage was first reported, London and South Africa respectively. Using the software tool grinch (global report investigating novel coronavirus haplotypes), we track the international spread of lineages of concern with automated daily reports, Further, we have built a custom tracking website (cov-lineages.org/global_report.html) which hosts this daily report and will continue to include novel SARS-CoV-2 lineages of concern as they are detected., Competing Interests: No competing interests were disclosed., (Copyright: © 2021 O'Toole Á et al.)
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- 2021
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