scholarly journals Stable Integration Vector for Nutrient Broth-Based Selection of Attenuated Listeria monocytogenes Strains with Recombinant Antigen Expression

2008 ◽  
Vol 15 (9) ◽  
pp. 1414-1419 ◽  
Author(s):  
Laurel L. Lenz ◽  
William A. Huang ◽  
Chenghui Zhou ◽  
Zhongxia Li ◽  
Richard Calendar
Keyword(s):  
Listeria Monocytogenes ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Antigen Expression ◽  
Vector System ◽  
Antigen Delivery ◽  
Integration Vector ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Cellular Immune

ABSTRACT Recombinant Listeria monocytogenes strains induce strong cellular immune responses and may prove useful for antigen delivery for the vaccination of humans. However, the genetic systems currently available for the stable expression of recombinant antigens by L. monocytogenes rely on the use of antibiotic resistance genes. We report on a derivative, pPL2dalGlnA, of the Listeria monocytogenes pPL2 integration vector that completely lacks drug resistance genes. The selectable markers in pPL2dalGlnA are glutamine synthetase (GlnA) and alanine racemase (Dal). This novel vector was stably maintained in auxotropic L. monocytogenes strains that normally require d-alanine. The pPL2dalGlnA vector also partially restored the ability of an L. monocytogenes Δdal Δdat strain to colonize the spleens and livers of infected mice. A novel, highly attenuated strain of L. monocytogenes with quadruple deletions was also engineered by deleting the L. monocytogenes actA and plcB virulence genes from a Δdal Δdat strain. Infection of mice with recombinants of this mutant strain that express the antigen from pPL2dalGlnA were shown to elicit CD8+ T-cell responses to human immunodeficiency virus Tat. This vector system is thus useful for stable antigen expression and vaccination studies.

scholarly journals Comprehensive Epitope Analysis of Human Immunodeficiency Virus Type 1 (HIV-1)-Specific T-Cell Responses Directed against the Entire Expressed HIV-1 Genome Demonstrate Broadly Directed Responses, but No Correlation to Viral Load

2003 ◽  
Vol 77 (3) ◽  
pp. 2081-2092 ◽  
Author(s):  
M. M. Addo ◽  
X. G. Yu ◽  
A. Rathod ◽  
D. Cohen ◽  
R. L. Eldridge ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Responses ◽  
Protein Subunits ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Immunodeficiency Virus ◽  
Total Magnitude ◽  
Cellular Immune ◽  
Hiv 1

ABSTRACT Cellular immune responses play a critical role in the control of human immunodeficiency virus type 1 (HIV-1); however, the breadth of these responses at the single-epitope level has not been comprehensively assessed. We therefore screened peripheral blood mononuclear cells (PBMC) from 57 individuals at different stages of HIV-1 infection for virus-specific T-cell responses using a matrix of 504 overlapping peptides spanning all expressed HIV-1 proteins in a gamma interferon-enzyme-linked immunospot (Elispot) assay. HIV-1-specific T-cell responses were detectable in all study subjects, with a median of 14 individual epitopic regions targeted per person (range, 2 to 42), and all 14 HIV-1 protein subunits were recognized. HIV-1 p24-Gag and Nef contained the highest epitope density and were also the most frequently recognized HIV-1 proteins. The total magnitude of the HIV-1-specific response ranged from 280 to 25,860 spot-forming cells (SFC)/106 PBMC (median, 4,245) among all study participants. However, the number of epitopic regions targeted, the protein subunits recognized, and the total magnitude of HIV-1-specific responses varied significantly among the tested individuals, with the strongest and broadest responses detectable in individuals with untreated chronic HIV-1 infection. Neither the breadth nor the magnitude of the total HIV-1-specific CD8+-T-cell responses correlated with plasma viral load. We conclude that a peptide matrix-based Elispot assay allows for rapid, sensitive, specific, and efficient assessment of cellular immune responses directed against the entire expressed HIV-1 genome. These data also suggest that the impact of T-cell responses on control of viral replication cannot be explained by the mere quantification of the magnitude and breadth of the CD8+-T-cell response, even if a comprehensive pan-genome screening approach is applied.

scholarly journals Aviremia 10 Years Postdiscontinuation of Antiretroviral Therapy Initiated During Primary Human Immunodeficiency Virus-1 Infection and Association With Gag-Specific T-Cell Responses

2015 ◽  
Vol 2 (4) ◽  
Author(s):  
Sabine Kinloch-de Loes ◽  
Lucy Dorrell ◽  
Hongbing Yang ◽  
Gareth A. D. Hardy ◽  
Sabine Yerly ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Antiretroviral Therapy ◽  
Viral Reservoir ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Cellular Immune ◽  
Drug Free ◽  
Human Immunodeficiency Virus 1

Abstract Combination antiretroviral therapy during primary human immunodeficiency virus-1 infection may enable long-term drug-free virological control in rare individuals. We describe a female who maintained aviremia and a normal CD4+/CD8+ T cell ratio for 10 years after stopping therapy, despite a persistent viral reservoir. Cellular immune responses may have contributed to this outcome.

scholarly journals Effects of Regulatory T Cell Depletion on NK Cell Responses against Listeria monocytogenes in Feline Immunodeficiency Virus Infected Cats

Viruses ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 984
Author(s):  
Simões ◽  
LaVoy ◽  
Dean
Keyword(s):  
Immune Response ◽  
Listeria Monocytogenes ◽  
Dendritic Cell ◽  
Innate Immune Response ◽  
Feline Immunodeficiency Virus ◽  
Innate Immune ◽  
Treg Depletion ◽  
Cell Responses ◽  
Immunodeficiency Virus

Regulatory T cells (Treg) are key players in the maintenance of peripheral tolerance, preventing autoimmune diseases and restraining chronic inflammatory diseases. Evidence suggests Treg cells and NK cells have important roles in feline immunodeficiency virus (FIV) pathogenesis; however, in vivo studies investigating the interplay between these two cell populations are lacking. We previously described innate immune defects in FIV-infected cats characterized by cytokine deficits and impaired natural killer cell (NK) and NK T cell (NKT) functions. In this study, we investigated whether in vivo Treg depletion by treatment with an anti-feline CD25 monoclonal antibody would improve the innate immune response against subcutaneous challenge with Listeria monocytogenes (Lm). Treg depletion resulted in an increased overall number of cells in Lm-draining lymph nodes and increased proliferation of NK and NKT cells in FIV-infected cats. Treg depletion did not normalize expression of perforin or granzyme A by NK and NKT cells, nor did Treg depletion result in improved clearance of Lm. Thus, despite the quantitative improvements in the NK and NKT cell responses to Lm, there was no functional improvement in the early control of Lm. CD1a+ dendritic cell percentages in the lymph nodes of FIV-infected cats were lower than in specific-pathogen-free control cats and failed to upregulate CD80 even when Treg were depleted. Taken together, Treg depletion failed to improve the innate immune response of FIV-infected cats against Lm and this may be due to dendritic cell dysfunction.

scholarly journals Conditional Lethality Yields a New Vaccine Strain of Listeria monocytogenes for the Induction of Cell-Mediated Immunity

2005 ◽  
Vol 73 (8) ◽  
pp. 5065-5073 ◽  
Author(s):  
Zhongxia Li ◽  
Xinyan Zhao ◽  
Darren E. Higgins ◽  
Fred R. Frankel
Keyword(s):  
Listeria Monocytogenes ◽  
Inducible Promoter ◽  
Vector System ◽  
Cell Mediated Immunity ◽  
Multicopy Plasmid ◽  
Listeriolysin O ◽  
Delivery Vector ◽  
Immunodeficiency Virus ◽  
Dependent Growth

ABSTRACT Listeria monocytogenes is a gram-positive intracellular pathogen that can enter phagocytic and nonphagocytic cells and colonize their cytosols. Taking advantage of this property to generate an intracellular vaccine delivery vector, we previously described a mutant strain of L. monocytogenes, Δdal Δdat, which is unable to synthesize cell wall by virtue of deletions in two genes (dal and dat) required for d-alanine synthesis. This highly attenuated strain induced long-lived protective systemic and mucosal immune responses in mice when administered in the transient presence of d-alanine. We have now increased the usefulness of this organism as a vaccine vector by use of an inducible complementation system that obviates the need for exogenous d-alanine administration. The strain expresses a copy of the Bacillus subtilis racemase gene under the control of a tightly regulated isopropyl-β-d-thiogalactopyranoside (IPTG)-inducible promoter present on a multicopy plasmid. This bacterium demonstrates strict dose-dependent growth in the presence of IPTG. After removal of inducer, bacterial growth ceased within two replication cycles. Following infection of mice in the absence of IPTG or d-alanine, the bacterium survived in vivo for less than 3 days. Nevertheless, a single immunization elicited a state of long-lasting protective immunity against wild-type L. monocytogenes and induced a subset of effector listeriolysin O-specific CD11a+ CD8+ T cells in spleen and other tissues that was strongly enhanced after secondary immunization. This improved L. monocytogenes vector system may have potential use as a live vaccine against human immunodeficiency virus, other infectious diseases, and cancer.

scholarly journals Magnitude and Quality of Vaccine-Elicited T-Cell Responses in the Control of Immunodeficiency Virus Replication in Rhesus Monkeys

2008 ◽  
Vol 82 (17) ◽  
pp. 8812-8819 ◽  
Author(s):  
Yue Sun ◽  
Sampa Santra ◽  
Jörn E. Schmitz ◽  
Mario Roederer ◽  
Norman L. Letvin
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
Rhesus Monkeys ◽  
T Cell Responses ◽  
Viral Control ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Immunodeficiency Virus ◽  
Cellular Immune ◽  
Functional Profiles

ABSTRACT While a diversity of immunogens that elicit qualitatively different cellular immune responses are being assessed in clinical human immunodeficiency virus vaccine trials, the consequences of those varied responses for viral control remain poorly understood. In the present study, we evaluated the induction of virus-specific T-cell responses in rhesus monkeys using a series of diverse vaccine vectors. We assessed both the magnitude and the functional profile of the virus-specific CD8+ T cells by measuring gamma interferon, interleukin-2, and tumor necrosis factor alpha production. We found that the different vectors generated virus-specific T-cell responses of different magnitudes and with different functional profiles. Heterologous prime-boost vaccine regimens induced particularly high-frequency virus-specific T-cell responses with polyfunctional repertoires. Yet, immediately after a pathogenic simian-human immunodeficiency virus (SHIV) challenge, no significant differences were observed between these cohorts of vaccinated monkeys in the magnitudes or the functional profiles of their virus-specific CD8+ T cells. This finding suggests that the high viral load shapes the functional repertoire of the cellular immune response during primary infection. Nevertheless, in all vaccination regimens, higher frequency and more polyfunctional vaccine-elicited virus-specific CD8+ T-cell responses were associated with better viral control after SHIV challenge. These observations highlight the contributions of both the quality and the magnitude of vaccine-elicited cellular immune responses in the control of immunodeficiency virus replication.

scholarly journals Regulated Antigen Expression in Live RecombinantSalmonella enterica Serovar Typhimurium Strongly Affects Colonization Capabilities and Specific CD4+-T-Cell Responses

2001 ◽  
Vol 69 (12) ◽  
pp. 7493-7500 ◽  
Author(s):  
Dirk Bumann
Keyword(s):  
T Cell ◽  
T Cell Responses ◽  
Antigen Expression ◽  
Cell Receptor ◽  
Cell Responses ◽  
Wide Range ◽  
Serovar Typhimurium ◽  
Cellular Immune

ABSTRACT Regulated antigen expression can influence the immunogenicity of live recombinant Salmonella vaccines, but a rational optimization has remained difficult since important aspects of this effect are incompletely understood. Here, attenuated Salmonella enterica serovar Typhimurium SL3261 strains expressing the model antigen GFP_OVA were used to quantify in vivo antigen levels by flow cytometry and to simultaneously follow the crucial early steps of antigen-specific T-cell responses in mice that are transgenic for a T-cell receptor recognizing ovalbumin. Among seven tested promoters,P pagC has the highest activity in murine tissues combined with low in vitro expression, whereasP tac has a comparable in vivo and a very high in vitro activity. Both SL3261 (pPpagCGFP_OVA) and SL3261 (pPtacGFP_OVA) cells can induce potent ovalbumin-specific cellular immune responses following oral administration, but doses almost 1,000-fold lower are sufficient for the in vivo-inducible construct SL3261 (pPpagCGFP_OVA) compared to SL3261 (pPtacGFP_OVA). This efficacy difference is largely explained by impaired early colonization capabilities of SL3261 (pPtacGFP_OVA) cells. Based on the findings of this study, appropriate in vivo expression levels for any given antigen can be rationally selected from the increasing set of promoters with defined properties. This will allow the improvement of recombinantSalmonella vaccines against a wide range of pathogens.

scholarly journals Of mice, macaques and men: scaling of virus dynamics and immune responses

2015 ◽  
Author(s):  
Christian L Althaus
Keyword(s):  
Immune Responses ◽  
Allometric Scaling ◽  
Rhesus Macaques ◽  
Lymphocytic Choriomeningitis ◽  
The Body ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Infection Dynamics ◽  
Immunodeficiency Virus ◽  
Cellular Immune

In this Opinion piece, I argue that the dynamics of viruses and the cellular immune response depend on the body size of the host. I use allometric scaling theory to interpret observed quantitative differences in the infection dynamics of lymphocytic choriomeningitis virus (LCMV) in mice (Mus musculus), simian immunodeficiency virus (SIV) in rhesus macaques (Macaca mulatta) and human immunodeficiency virus (HIV) in humans. There are indications that viral replication and the proliferation of CD8+ T cell responses are slower in larger animals. Whether this influences the ability of the cellular immune responses to eradicate viruses during the acute phase of an infection remains unclear, however.

scholarly journals Antimicrobial Susceptibility, Serotyping, and Molecular Characterization of Antibiotic Resistance Genes in Listeria monocytogenes Isolated from Pregnant Women with a History of Abortion

2021 ◽  
Author(s):  
Siamak HEIDARZADEH ◽  
Mohammad Reza POURMAND ◽  
Saeedeh HASANVAND ◽  
Reyhaneh PIRJANI ◽  
Davoud AFSHAR ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Pregnant Women ◽  
Resistance Genes ◽  
Antimicrobial Agents ◽  
Tertiary Care ◽  
Antibiotic Resistance Genes ◽  
Diffusion Method ◽  
Care Hospital ◽  
Disk Diffusion Method ◽  
History Of

Background: Listeria monocytogenes show high mortality among pregnant women and newborns. This study aimed to detect L. monocytogenes in pregnant women with a history of abortion and assess the serotypes, antibiotic susceptibility patterns, and its resistance genes. Methods: Overall, 400 vaginal swabs were taken from pregnant women with a history of abortion in the past few years in a tertiary care hospital in Tehran, Iran, during 2015-2018. Antibiotics susceptibility to a panel of 10 antibiotics was determined using the standard disk diffusion method and the isolates serotyped by the agglutination method. The antimicrobial-resistant isolates were also screened for the presence of tetM, ermB and dfrD genes by PCR. Results: Overall, 22 L. monocytogenes isolates were identified. High rates of resistance were observed for trimethoprim (50%; n=11), sulphamethoxazole (50%; n=11), tetracycline (45.45%; n=10) and gentamicin (36.36%; n=8). From 22 L. monocytogenes isolates, 13 (59.10 %), 5 (22.73%), 3 (13.63%) and 1 (4.54%) belonged to serotypes 4b, 1/2a, 1/2b, and 3c, respectively. The genetic determinant tetM was detected in 70% of the tetracycline-resistant isolates. Out of 11 trimethoprim-resistant isolates, 27.27% isolates contained dfrD. Moreover, the ermB gene was found in 83.33% of the erythromycin-resistant isolates. Conclusion: Ampicillin and partly penicillin consider to be suitable antimicrobial agents to treat human listeriosis. Moreover, due to resistance against many antibiotics, it is necessary to continue monitoring and managing antimicrobial resistance.

scholarly journals Dynamics of T-Cell Responses and Memory T Cells during Primary Simian Immunodeficiency Virus Infection in Cynomolgus Macaques

2007 ◽  
Vol 81 (24) ◽  
pp. 13456-13468 ◽  
Author(s):  
Ingrid Karlsson ◽  
Benoît Malleret ◽  
Patricia Brochard ◽  
Benoît Delache ◽  
Julien Calvo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Peripheral Blood ◽  
Primary Infection ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Immunodeficiency Virus ◽  
Cynomolgus Macaques ◽  
Cellular Immune

ABSTRACT Cellular immune responses make an important contribution to both the control of human immunodeficiency virus (HIV) replication and disease progression. We used a pathogenic model of SIVmac251 infection of cynomolgus macaques to longitudinally evaluate cellular immune responses in association with various rates of disease progression. We found an inverse relationship between plasma viral load and the simian immunodeficiency virus (SIV)-specific T cells responses in peripheral blood and lymph nodes. SIV-specific T-cell responses in peripheral blood were transient during primary infection, with the highest responses detected around 3 months after infection. There was also a transient increase of central memory CD8+ T cells in peripheral blood during primary infection, and effector memory T-cell counts in peripheral lymph nodes were increased. This study emphasizes the importance of the early virus-specific immune responses in the outcome of HIV/SIV disease and provides details about the changes of virus-specific immune responses over time.

scholarly journals Optimal Induction of T-Cell Responses against Hepatitis C Virus E2 by Antigen Engineering in DNA Immunization

2003 ◽  
Vol 77 (21) ◽  
pp. 11596-11602 ◽  
Author(s):  
Jin-Won Youn ◽  
Su-Hyung Park ◽  
Jae Ho Cho ◽  
Young Chul Sung
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
T Cell ◽  
Immune Responses ◽  
Transmembrane Domain ◽  
T Cell Responses ◽  
Dna Immunization ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Cellular Immune

ABSTRACT Although DNA immunization is a safe and efficient method for inducing cellular immune responses, it generates relatively weak and slow immune responses. Here, we investigated the effect of hepatitis C virus (HCV) antigen modifications on the induction of T-cell responses in DNA immunization. It is likely that the strength of T-cell responses has an inverse relationship with the length of the insert DNA. Interestingly, a mixture of several plasmids carrying each gene induced a higher level of T-cell responses than a single plasmid expressing a long polyprotein. Moreover, the presence of a transmembrane domain in HCV E2 resulted in stronger T-cell responses against E2 protein than its absence. Taken together, our results indicate that the tailored modifications of DNA-encoded antigens are capable of optimizing the induction of T-cell responses which is required for eliminating the cells chronically infected with highly variable viruses such as HCV and human immunodeficiency virus.

Sign in / Sign up

Export Citation Format

Share Document