Zoltan Kis

Chlamydophila (Chlamydia) pneumoniae induces histidine decarboxylase production in the mouse lung

Chlamydophila (Chlamydia) pneumoniae (C. pneumoniae) is the third most common cause of community-acquired pneumonia and is probably involved in the development of certain chronic inflammatory diseases, including atherosclerosis and adult-onset asthma. Histamine, synthesized by histidine decarboxylase (HDC) from L-histidine, plays an essential role in allergic and inflammatory processes and in cell differentiation. The effect of C. pneumoniae infection on the expression of HDC has not been examined. In the present study, normal Balb/c mice and HDC knockouts, and control mice with a CD1 background were infected intranasally with C. pneumoniae. On days 1, 3, 7, 16 and 31 after infection, the normal Balb/c mice were sacrificed and divided into three groups. In the homogenized lungs of the first group, C. pneumoniae titres were determined and demonstrated peak levels on day 7. HDC production was revealed by a Western blot assay throughout the observation period of 1-16 days, and cytokine concentrations were determined by ELISA. The interleukin-3 (IL-3) and interleukin-6 (IL-6) levels were highest on day 1 and on days 1-3, respectively; the interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) levels reached the maximum on day 7, but the quantity of IL-4 was still three times higher than that in the control group 16 days after infection. The lungs of the mice in the second group were processed for the in situ demonstration of HDC activity, while the lungs in the third group were stained for C. pneumoniae antigen. The HDC activity was increased predominantly in the bronchial epithelial cells, while C. pneumoniae antigens were expressed especially in the interstitial macrophages. The HDC knockout mice exhibited a higher survival rate after C. pneumoniae infection than did the control mice. These results point to a strong association between local histamine production and other inflammatory mediators and are novel in demonstrating the role of histamine in the pathomechanism of C. pneumoniae infections.

Detection of Human Bocavirus from Fecal Samples of Hungarian Children with Acute Gastroenteritis

Objectives: Human bocavirus (HBoV), a newly identified member of the Parvoviridae family is associated with respiratory tract and gastroenteric infections, mostly of young children. HBoV infections show a seasonal distribution with the peak in temperate areas being in the winter months. Methods: In our study, 35 throat swabs from children under 5 years with acute respiratory symptoms and 61 stool samples from children (<5 years) with acute gastroenteritis were collected in the period of October 2007–March 2008. A HBoV-specific polymerase chain reaction for detection of the virus, and sequence analysis for identification of virus variants were performed. Results: Although respiratory samples were all negative, 3.3% of stool samples (2/61) proved to be positive for HBoV. The virus carrier children were 3 and 5 years old. The ratio of HBoV positive samples is similar to international results (2.1–5.5%). Conclusions: According to the result of sequence analysis of HBoV, the occurrence of genotype 2 of HBoV in Hungary is confirmed.

Chronic infections and histamine, CRP and IL-6 levels after percutaneous transluminal coronary angioplasty

Abstract.Objective and design:Our hypothesis was that percutaneous transluminal coronary angioplasty (PTCA) reactivates certain pathogens that contribute to inflammatory processes after the intervention.Subjects:We determined the levels of antibodies to human Hsp60 and levels of histamine, CRP and IL-6 in sera from 28 patients of unstable angina prior to and on days 4 and 14 after PTCA. We compared the presence of Chlamydophila pneumoniae (Cpn) and human cytomegalovirus (HCMV) DNA in peripheral blood, and levels of antibodies to Cpn, HCMV, herpes simplex virus, Epstein-Barr virus and mycobacterial Hsp65 in the serum.Results:Higher prevalence of Cpn and HCMV DNA was demonstrated after PTCA than before, but titers of antibodies to the pathogens did not increase. Levels of histamine, CRP and IL-6 were enhanced after PTCA. There was no association between the levels of histamine, CRP and IL-6 and the rate of pathogen DNA, or antibody titers to the pathogens, except an association between Cpn IgA and histamine levels before PTCA.Conclusions:Reactivation of Cpn and HCMV and inflammatory change characterized by increased levels of histamine, CRP and IL-6 following PTCA are suggested. An association might exist between Cpn IgA antibody and histamine levels in patients of unstable angina.

Inflammatory- and immune responses in relation to bacterial replication in mice following re-infections with Chlamydophila pneumoniae

Abstract.Objective:Investigation of chronic infections with Chlamydophila pneumoniae.Methods:BALB/c mice were repeatedly infected with C. pneumoniae and tested during a 1-year period. Production of histamine, IFN-γ, IL-6 and antibodies was monitored by ELISA. Live bacteria were cultured and DNA was detected by PCR. Cellular immunity was tested by ELISPOT.Results:After re-infections, culture positivity and persistence of DNA in lungs and blood were shorter. Detection of DNA at late time points indicated persistent infection in a few mice. Histamine was produced after primary and re-infections, and the level correlated with the number of viable bacteria in lung. IFN-γ, IL-6 levels, IgG2/IgG1 ratio, IgA titres, and level of chlamydial heat-shock protein antibodies were higher after re-infections. IgM antibodies were demonstrated even after re-infections. High number of IFN-γ-producing splenocytes was observed after the third inoculation.Conclusion:These results promote an understanding of the patho- and immune mechanisms after C. pneumoniae re-infections.

Expression of bacterial genes and induction of INF‐γ in human myeloid dendritic cells during persistent infection with Chlamydophila pneumoniae

The interactions between human monocyte-derived dendritic cells (DCs) and Chlamydophila pneumoniae (Cpn) infection were investigated. Cpn infection induced the maturation and functional activation of DCs, and Cpn antigens were present in all of the subpopulations during the maturation process. Chlamydial antigens were detected in DCs during an observation period of 28 days. The exponential production of infectious elementary bodies was not observed. Chlamydial transcripts of the 16S rRNA gene, groEL-1 and omcB genes were expressed, as determined by a quantitative real-time PCR, but the expression of the ftsK gene was limited. DC cultures produced IFN-gamma, but the presence of IFN-gamma in the culture medium was not the major factor that decreased the growth of Cpn, as was shown by neutralization of the IFN-gamma. A cell population identified as producing IFN-gamma had no markers for T, B, natural killer, monocyte cells or macrophages but displayed DC morphology and the expression of specific DC markers, such as CD11c and HLA-DR. These results reveal a persistent infection of DCs with the expression of some, but not cell division-related genes and the production of IFN-gamma that may contribute to the pathomechanism of chronic inflammatory diseases associated with persistent Cpn infection.

A soluble factor(s) released by MRC-5 cells early and late after human cytomegalovirus infection induces maturation of monocyte-derived dendritic cells

Summary.A human cytomegalovirus (HCMV) strain passaged 10 times on MRC-5 human fibroblast cells failed to express immediate early (IE) antigens in immature dendritic cells (iDCs) after infection. However, both the early and the late HCMV conditioning medium, harvested from MRC-5 cells at 24u2009h or 7–9 days after infection, respectively, induced a higher ratio of DCs expressing maturation markers (CD40, CD83, CD86 and HLA-DR) on the surface of the cells. HCMV conditioning medium, ultracentrifuged to remove virus particles, exhibited a similarly enhanced expression of DC maturation markers. DCs treated with HCMV conditioning medium harvested late after infection increased the percentages of autologous CD4+ and CD8+ cells of seropositive donors to produce IFN-γ and stimulated HCMV-specific lymphoproliferative responses. The early HCMC conditioning medium was also able to induce the functional maturation of DCs, as demonstrated by supplementing this medium with a Chlamydia pneumoniae antigen.

High-Level Cellular and Humoral Immune Responses in Guinea Pigs Immunized Intradermally with a Heat-Inactivated Varicella-Zoster Virus Vaccine

ABSTRACT The threat of varicella and herpes zoster in immunocompromised individuals necessitates the development of a safe and effective varicella-zoster virus (VZV) vaccine. The immune responses of guinea pigs to the intradermal (i.d.) or subcutaneous (s.c.) administration of a heat-inactivated or live VZV vaccine were investigated. Relative to nonimmunized animals, a single 399-PFU dose of vaccine induced nonsignificant increases in gamma interferon (IFN-γ), granzyme B, and perforin mRNA expression in the splenocytes of all groups, while two i.d. administrations of the inactivated vaccine increased IFN-γ mRNA expression significantly (P < 0.005). A single 1,995-PFU dose significantly increased the expression of IFN-γ mRNA in the groups receiving the vaccine either i.d. (P < 0.005) or s.c. (P < 0.05), that of granzyme B mRNA in the groups immunized i.d. with the inactivated (P < 0.005) or live (P < 0.005) vaccine, and that of perforin mRNA in the animals that received the inactivated vaccine i.d. (P < 0.005). Importantly, increases in the expression of IFN-γ (P = 0.025), granzyme B (P = 0.004), and perforin (P > 0.05) mRNAs were observed in the animals immunized i.d. with 1,995 PFU of inactivated vaccine relative to those immunized s.c. with the same dose. The proportion of animals expressing IFN-γ mRNA mirrored the proportion expressing IFN-γ protein (correlation coefficient of 0.88). VZV glycoprotein-specific and virus-neutralizing antibodies were produced with no significant intergroup differences. A booster i.d. administration of the 399-PFU dose of heat-inactivated vaccine enhanced the antibody responses. These results demonstrate that i.d. administration of an inactivated VZV vaccine can be an efficient mode of immunization against VZV.

Protection of Chinese painted quails (Coturnix chinensis) against a highly pathogenic H5N1 avian influenza virus strain after vaccination

Chinese painted quails immunized with a single dose (6xa0μg HA) of inactivated H5N1 (clade 1) influenza vaccine NIBRG-14 and challenged with 100 LD50 of the heterologous A/Swan/Nagybaracska/01/06(H5N1) (clade 2.2) strain were protected, whereas unvaccinated quails died after challenge. No viral antigens or RNA were detected in cloacal swabs from immunized animals. Sera obtained post-immunization gave low titres in serological assays against the vaccine and the challenge viruses. Our results demonstrate the protective efficacy of the NIBRG-14 strain against the challenge virus and the usefulness of these small birds in protection studies of influenza vaccines.

Correction for Sarkadi et al., High-Level Cellular and Humoral Immune Responses in Guinea Pigs Immunized Intradermally with a Heat-Inactivated Varicella-Zoster Virus Vaccine

Volume 22, no. 5, p. [570–577][1], 2015. Page 576: The first paragraph of the Acknowledgments section should read as follows. “We thank the FastVac and the UNISEC consortia funded by the Health and the Research Programmes of the European Union and the participating member states for their