Expansion of CD4+ CD25+ FoxP3+ regulatory T cells in chronic hepatitis C virus infection

BACKGROUND

Regulatory T cells (Tregs) have been involved in impaired immunity and may have a pivotal role in persistence of viral infections.

OBJECTIVE

To develop a simple and reliable in-house three color flow cytometery of peripheral blood to understand the role of HCV infection in the increase of Tregs.

METHODS

The level of naturally occurring CD4+ CD25+ FoxP3+ regulatory T cells (nTregs) in 20 chronically infected with hepatitis C virus (HCV) patients was compared to those of 15 healthy individuals by flowcytometry. In a different approach we performed permeabilization and intracellular staining before surface staining which allows the preservation of the surface molecules in the combined detection process and results in the normal frequency of nTregs in blood.

RESULTS

Using the optimized method, it was shown that a significantly higher proportion of nTregs in the total CD4+ T cell population was seen in the peripheral blood of chronic HCV patients (0.83 ± 0.21%, p=0.05) as compared to controls (0.26 ± 0.1, p=0.05).

CONCLUSIONS

In accordance with other studies, we showed that HCV infection induces a dramatic increase in Tregs, which might contribute to the immune response failure during HCV infection.

The effect of herpes simplex virus virion host shutoff gene- a new suicide gene- on tumor cells

BACKGROUND

The herpes simplex virus (HSV) UL41 gene product, virion host shutoff (Vhs) protein, mediates the rapid degradation of both viral and cellular mRNA. This ability suggests that Vhs protein can be used as a suicide gene in cancer gene therapy applications. The recent reports have shown that the degradation of cellular mRNA during herpes simplex infection is selective. RNA containing AU-rich elements (ARE) in their 3' untranslated ends are the targets for the Vhs protein. RNA that are not subject to Vhs protein-dependent degradation are up-regulated during HSV infection. ARE are frequently found in mRNA that encode proto-oncogenes, nuclear transcription factors, and cytokines. In many human cancers, the AU-rich stretch of proto-oncogenes and regulatory genes has impaired.

METHODS

To investigate whether Vhs protein might be useful for inhibition of tumor cell proliferation, a eukaryotic expression vector containing Vhs protein gene was constructed. Cell degradation and RNA content of HeLa and MRC-5 tumor cells after transfection with the constructed vector were studied.

RESULTS

The results showed a strong inhibitory activity in proliferation of transfected tumor cells and a sharp decrease in their RNA content.

CONCLUSION

These data suggest that Vhs protein can be considered as a candidate for suicide cancer gene therapy.

[A kinetic study of gamma interferon production in herpes simplex virus-1 DNA prime-protein boost regimen comparing to DNA or subunit vaccination]

The vast majority of the world's population is infected with Herpes simplex virus (HSV). Although antiviral therapy can reduce the incidence of reactivation and asymptomatic viral shedding, and limit morbidity and mortality from active disease, it cannot cure infection. Therefore, the development of an effective vaccine is an important global health priority. In this study, the induction of IFN-gamma production was compared by different herpes simplex virus 1 (HSV1) vaccines. Glycoprotein D (gD1) as a major immunogenic HSV1 glycoprotein was chosen to our study. Balb/c mice were administered with DNA vaccine encoding gD1, subunit glycoprotein vaccine including insect cells infected by a gD1 recombinant Baculovirus, prime DNA vaccine boosted by subunit glycoprotein vaccine, inactivated KOS strain as a positive control, PcDNA3 plasmid and Sf9 cells as a negative control. Evaluation tests showed kinetics of IFN-gamma mRNA at 8, 16 and 32 hours after restimulation sharply decreased whereas, IFN-gamma protein is significantly increased. Our results revealed that at 14 days after immunization IFN-gamma secretion of stimulated cells in all of the vaccinate groups dramatically raised rather than secreted IFN-gamma levels in mice that were analyzed at 7 days after vaccination. In comparison to other groups; Prime-Boost immunization dramatically caused vigorous and prompt IFN-gamma production at 7 days after immunization and 8 hours after restimulation.

Kinetics of primary and memory cytotoxic T lymphocyte responses to herpes simplex virus 1 infection: granzyme B mediated CTL activity

BACKGROUND

Herpes simplex virus type 1 is one of the most common viruses among human population. Studies demonstrate the essential role of cell mediated immunity, especially CD8+ T cells, in prevention and clearance of HSV1.

OBJECTIVE

It is of great importance to improve our knowledge about the kinetics of CTL responses to primary and secondary HSV-1 infection.

METHODS

Using a sensitive technique for detection and analysis of CD8+ T cells, granzyme B ELISA, the CTL activity in the spleens of Balb/c mice at various time points after intraperitoneal administration of HSV1 (strain KOS) in primary and secondary infections were determined.

RESULTS

During acute HSV-1 infection, virus specific cytotoxic T cells were detected at day 5 post virus inoculation and peaked at day 7. Six hours after secondary infection the activity of memory CD8+ T cells was detected and peaked at 12 hours post infection.

CONCLUSION

The peak of CTL activity was found to be day 7 post infection in primary HSV-1 infections which decreased with time. In secondary infections, the activity of CTLs reached the highest level at 12 hours post infection.

A novel adjuvant, the general opioid antagonist naloxone, elicits a robust cellular immune response for a DNA vaccine

While many adjuvants have been discovered and used in research, only a few adjuvants have been permitted for use with human vaccination. We have previously shown that the administration of naloxone (NLX), a general opioid antagonist, during infection with a non-virulent strain of herpes simplex virus type 1 (HSV-1) could enhance protection against HSV-1 challenge. Here, the adjuvant activity of NLX has been evaluated using a DNA vaccine for HSV-1 as a model. BALB/c mice were divided into four groups; for experimental groups, mice received the glycoprotein D1 (gD1) DNA vaccine alone or in combination with the adjuvant NLX. A positive control group received the KOS strain of HSV-1, and a negative control group received PBS. All mice were immunized three times on days 0, 21 and 42. Three weeks after the last immunization, immune responses against HSV-1 were assessed. Our results indicate that the administration of NLX as an adjuvant increased the ability of the gD1 DNA vaccine to enhance cytolytic T lymphocyte activity, lymphocyte proliferation, delayed-type hypersensitivity and shifting the immune response toward a T helper (Th)1 pattern and improved protective immunity against HSV-1. NLX also increased the IgG2a/IgG1 ratio, though it did not affect the production of HSV-1 antiserum. In conclusion, administration of NLX as an adjuvant in combination with the gD1 DNA vaccine can enhance cell-mediated immunity and shift the immune responses to Th1.

Enrichment of cerebrospinal fluid samples on cell culture for enhancement of sensitivity of mumps and enterovirus detection by multiplex RT-PCR

It has been demonstrated that the detection of enteroviruses and mumps virus nucleic acid in cerebrospinal fluid (CSF) specimens improves the management of the patients with aseptic meningitis. To determine the effect of overnight enrichment of mumps and enteroviruses in CSF samples on cell culture for increasing the sensitivity of viral detection, we developed a multiplex reverse transcriptase-polymerase chain reaction (RT-PCR). CSFs were collected from 100 patients younger than 7 years. The samples were tested for the presence of enteroviruses and mumps virus by multiplex RT-PCR method. Negative samples in Multiplex RT-PCR were enriched for viral template RNAs by overnight culture of CSF samples on cells and followed by the optimized Multiplex RT-PCR. Overall, 35% of the CSF samples were positive for enteroviruses, whereas only 1% of CSF samples were positive for both viruses. After enriching in cell culture, 34% of the negative samples showed a positive polymerase chain reaction band for enteroviruses, and a 3% increase was observed for both viruses. The results showed that enrichment of viral template RNAs in cell culture can increase the sensitivity of the multiplex RT-PCR assay and provide a rapid and sensitive method for detection of viral infections.

Naloxone, an opioid receptor antagonist, enhances induction of protective immunity against HSV-1 infection in BALB/c mice

The immunomodulatory effects of exogenous opioids on induction of acquired immunity during microbial infection are now well known; however, our knowledge about the relationship between endogenous opioid response and microbial infections is rudimentary. Here, we report the effect of administration of Naloxone (NLX), an opioid receptor antagonist, on induction of acquired immunity during primary herpes simplex virus type 1 (HSV-1) infection. BALB/c mice received NLX, twice daily, 2 h before infection with HSV-1 until 7 days after infection. Cell-mediated immunity was assessed by evaluating lymphocyte proliferation, interferon-gamma (IFN-gamma) production, delayed type hypersensitivity (DTH) and mortality rate after acute HSV-1 challenge. The findings showed that a higher level of cell-mediated immunity was induced in the NLX-treated animals compared to the control group after induction of HSV-1 infection. However, the data indicate similar neutralizing antibody production in NLX-treated animals and control animals. This observation and further studies in this field may lead to the use of NLX as an adjuvant for designing microbial vaccines and adjunctive therapy of viral infections.

Induction of humoral and cellular immunity against latent HSV-1 infections by DNA immunization in BALB/c mice

Previously, we have reported that the injection of an expression vector containing Herpes simplex virus (HSV) Glycoprotein D-1 (gD-1) generated a significant antibody response in mice and protected them against HSV lethal challenge. We tested its potential to induce antibody and cell mediated immune responses in latently infected mice. Positive control group (KOS) and HSV gD-1 vaccinated mice demonstrated protection against a lethal ocularly challenge of 10(5.5) plaque-forming units (pfu)/eye of wild HSV-1 versus negative control groups. For neutralizing antibody titers, delayed-type hypersensitivity (DTH), lymphocyte proliferation responses, clinical evaluation and survival following lethal challenge, no considerable difference was observed between mice vaccinated with DNA plasmid and those vaccinated with KOS. KOS-vaccinated mice demonstrated the ability to completely prevent latency whereas DNA vaccinated group showed some degree of protection and displayed less latency than negative control groups and had considerably high levels of IFN-gamma and strong CTL responses versus negative control groups. It can be concluded that although immunization with the DNA vaccine is more effective in both protecting mice and induction of immune response, however it could not completely block the latent infection in sensory nerves.

DNA vaccine-encoded glycoprotein B of HSV-1 fails to protect chronic morphine-treated mice against HSV-1 challenge

The use of morphine has been demonstrated to increase susceptibility to infections. Herpes simplex virus type 1 (HSV-1) is a highly successful pathogen among immunocompromised individuals. In the present study, due to the importance of HSV vaccination in morphine abusers, the effects of chronic morphine exposure on the host response to a HSV-1 gB DNA-based vaccine have been investigated. The study is addressing an important aspect of vaccine development among the susceptible (immunocompromised) hosts. BALB/c mice were exposed to morphine over 11 days. They were then vaccinated with DNA vaccine or KOS strain as a live vaccine. The findings showed that the morphine-treated animals failed to respond to DNA vaccination evaluated by the anti-HSV gB antibody titer, delayed type hypersensitivity (DTH) and lethal HSV-1 challenge. Under the same conditions, the KOS vaccine showed a reduced Ab titer and DTH response in morphine-treated mice, but could protect mice against the lethal challenge and was safe for vaccination of morphine-treated animals.

Acute morphine administration reduces white blood cells' capability to induce innate resistance against HSV-1 infection in BALB/c mice

OBJECTIVE

It has been reported that acute morphine administration modulates innate immune response to herpes simplex virus 1 (HSV-1) infection. In this study, the effect of acute morphine on innate resistance and its probable mechanisms in increasing the mortality rate during HSV-1 infection were investigated.

METHODS

Mice were infected with HSV-1 24 h prior to different doses of morphine or saline administration and the mortality rate was recorded. Spleen cells were obtained from morphine- or saline-treated mice, then natural killer (NK) cell activity and interferon-gamma (IFN-gamma) production were evaluated. The effect of morphine on white blood cells' capacity to induce protection against HSV-1 infection was evaluated by adoptive transfer of spleen cells to cyclophosphamide-treated mice that were previously infected with HSV-1. Furthermore, in a separate experiment, a different group of mice received corticosterone 24 h after HSV-1 infection.

RESULTS

Mortality rate in high-dose acute morphine-treated mice increased significantly compared to saline-treated mice (p = 0.035). NK cell cytotoxicity and IFN-gamma mRNA levels also showed a significant reduction compared to those of control groups (p < 0.001 and p = 0.014, respectively). Corticosterone administration reduces innate resistance against HSV-1 infection compared to saline-treated mice (p = 0.044). Furthermore, adoptive transfer of normal but not morphine-treated spleen cells induces resistance against HSV infection in cyclophosphamide-injected mice (p = 0.009).

CONCLUSIONS

The current study shows that acute morphine administration reduces white blood cells' capability to induce protection against HSV-1 infection via suppression of IFN-gamma production and NK cells activity. This may be due to the increase in corticosteroids. Further studies are needed to test the effect of acute morphine on other immune cells.

Intercellular trafficking of VP22, a herpes simplex virus type 1 tegument protein

BACKGROUND

The herpes simplex virus type 1 (HSV-1) tegument protein, VP22 has been reported to have the property of intercellular transport. The previous studies have shown that following expression of a fusion protein containing VP22; it spreads to every cell in a monolayer and concentrates in the nucleus. In spite of these reports, some studies have shown that VP22 trafficking and its nucleus accumulation is an artifact and no improvement in translocation of proteins fused to VP22 has been detected.

METHODS

To better understand about VP22 translocation, VP22-GFP (Green Fluorescent Protein) vector was constructed and its nuclear accumulation, transportation to the nomtransfected cells and translocation between different cell types were studied by fluorescent microscope.

RESULTS

VP22-fusion protein was detected in nontransfected cells which in some of them the fusion protein was shown in nucleus.

CONCLUSION

The results demonstrated that VP22 can easily transport between different cells but nuclear accumulation of the protein is not common in all of the recipient cells.

Prevalence of HI antibody titer against rubella virus to determine the effect of mass vaccination in Tehran

BACKGROUND

Rubella is an infectious viral disease, has a worldwide distribution and is normally a mild childhood disease. Infection during early pregnancy may cause fetal death or congenital rubella syndrome. The highest risk of CRS is found in countries with high susceptibility rates among women of childbearing age. In many developed and some developing countries, large-scale rubella vaccination during the past decade has drastically reduced or practically eliminated rubella and CRS. Mass vaccination campaigns and Expanded Program of Immunization (EPI) have increased vaccine coverage in the world with a substantial impact on the reduction of rubella infections, such as CRS.

OBJECTIVE

The present study was preformed to evaluate the immune status against rubella before and after the mass campaign vaccination on 22 December 2003.

STUDY DESIGN

A total of 320 samples were collected from the healthy subjects before and after the vaccination and 80 paired sera were collected and tested for the presence of rubella antibody using HI test.

RESULTS AND CONCLUSIONS

Based on the results, 98.1% of the population has gained anti-rubella antibody, compared with 92.2% before the vaccination. The data revealed that 98.75% of the paired subjects had rubella antibody after mass vaccination which is statistically significant.

The effect of DNA priming-protein boosting on enhancing humoral immunity and protecting mice against lethal HSV infections

Herpes simplex virus produces primary and latent infections with periodic recurrency. The prime-boost immunization strategies were studied using a DNA vaccine carrying the full-length glycoprotein D-1 gene and a baculovirus-derived recombinant glycoprotein D, both expressing herpes simplex virus glycoprotein D-1 protein. Immunization with recombinant DNAs encoding antigenic proteins could induce cellular and humoral responses by providing antigen expression in vivo. Higher immune response, however, occurred when the recombinant proteins followed DNA inoculation. While all groups of the immunized mice and positive control group could resist virus challenge, a higher virus neutralizing antibody level was detected in the animals receiving recombinant protein following DNA vaccination.

Immunogenicity and protective effect of a DNA construct encoding certain neutralizing epitopes of herpes simplex virus type-1 glycoprotein B

Much attention is presently focused on the vaccination with certain epitopes of an antigen. To further study the ability of neutralizing epitopes mapped in the first 1515 nucleotides of glycoprotein B of herpes simplex virus type-1 (gB-1) to induce neutralizing antibodies, a DNA immunization approach was employed. Vaccination of mice with a plasmid expressing the neutralizing epitopes induced humoral immune responses, although the antibody titre was significantly lower than that of antibodies induced by the full-length gB-1 gene. Furthermore, the plasmid DNA could not protect the mice against HSV-1 lethal challenge, but could significantly prolong the survival time compared to mock-vaccinated group.