IMMUNOLOGY IN CROATIA 40th anniversary of the Croatian Immunological Society

This special issue is dedicated to the 40th Anniversary of organized activities of the Croatian Immunological Society. On this occasion the Annual Meeting of Croatian Immunological Society will be organized in [ibenik, October 9-12 2008, where this supplement will be introduced and distributed. The idea for such a collection of data was born (conceived) during my first presidency 10 years ago, when the first account of Croatian Immunological Society activities was published, in Croatian. This time, we have tried to include not only the founding and activities of Croatian Immunological Society but also all research groups working in the field of immunology in Croatia during the past 40 years. I wish to express my warmest thanks to all authors for their contributions. Especially for collecting all the relevant data, references and achievements of their research groups. From the collected data it is evident that Immunology in Croatia developed very fast (rapidly), and achieved a prominent place among scientific disciplines. Both national and international collaboration resulted in the establishment of new groups, not only at universities where immunology first started, but also at several institutes and hospitals in Zagreb and Rijeka. The number of Croatian Immunological Society members varies, being always more than one hundred and less than two hundred, but with a very good renewal rate of young members each year. We hope that, with improved financing policy of basic science in Croatia, more novices will be attracted, and that immunologists will remain as active as they were throughout this past 40 years, despite some quite untoward conditions. Sabina Rabatić guest edito

Targeting Toll-Like Receptors: a step closer to effective recombinant subunit vaccines

The control and prevention of infectious diseases through immunization is one of the greatest achievements of modern medicine since Edward Jenner pioneered smallpox vaccination. However, future challenges in improving the efficacy of existing vaccines, development of new prophylactic vaccines for infectious diseases and therapeutic immunization for noninfectious diseases require extensive work to reveal key components of the molecular immune mechanism involved. Successful activation of innate immune response is a prerequisite for successful immunization and activation of adaptive immunity. Innate immune system comprises numerous evolutionary conserved pattern-recognition receptors (PRRs) that bind structural components shared by many pathogens. Upon binding the ligand, cascade reaction results in de novo gene expression required for immediate immune response by innate immunity and the activation of specific immune response mediated by the humoral and cellular mediators. Appropriate selection of specific pattern-recognition receptor ligands (adjuvants) enables formulation of the next generation vaccines, with controlled minimal adverse symptoms and efficient adaptive immunity development

Expression of chemokine receptor CX3CR1 in infants with respiratory syncytial virus bronchiolitis

Respiratory syncytial virus (RSV) glycoprotein G mimics fractalkine, a CX(3)C chemokine, which mediates chemotaxis of leukocytes expressing its receptor, CX(3)CR1. The aim of this study was to examine the relationship between RSV infection and expression of perforin and IFN-gamma in CX(3)CR1-expressing peripheral blood CD8(+) T cells. Samples were collected from infants with RSV bronchiolitis, both in the acute and convalescence phase (n = 12), and from their age- and sex-matched healthy controls (n = 15). Perforin expression and IFN-gamma secretion in CX(3)CR1(+) CD8(+) T cells were assessed by four-color flow cytometry. The NF-kappaB p50 and p65 subunit levels were also determined as markers of RSV-induced inflammation. Study results showed perforin and CX(3)CR1 expression to be significantly lower in the convalescent phase of infected infants than in healthy controls. There was no significant difference in IFN-gamma secretion and NF-kappaB binding activity between two time-points in RSV-infected infants, or when compared with healthy controls. Infants with prolonged wheezing had lower acute-phase CX(3)CR1 levels in peripheral blood. These data indicate existence of an event persisting after acute RSV infection that is able to modulate effector functions of cytotoxic T cells, and also link disease severity with CX(3)CR1 expression

Circulating Lymphocyte Subsets, Natural Killer Cell Cytotoxicity, and Components of Hypothalamic-Pituitary-Adrenal Axis in Croatian War Veterans with Posttraumatic Stress Disorder: Cross-Sectional Study

Aim: To determine peripheral blood lymphocyte subsets – T cells, helper T cells, cytotoxic T cells, B cells, and natural killer cells, natural killer cell cytotoxicity, serum cortisol concentration, and lymphocyte glucocorticoid receptor expression in Croatian combat veterans diagnosed with chronic posttraumatic stress disorder (PTSD); and to examine the relationship between the assessed parameters and the time passed since the traumatic experience. Methods: Well-characterized group of 38 PTSD patients was compared to a group of 24 healthy civilians. Simultaneous determination of lymphocyte subsets and the expression of intracellular glucocorticoid receptor was performed using three-color flow cytometry. Natural killer cell cytotoxicity was measured by 51Cr-release assay and the serum cortisol concentration was determined by radioimmunoassay. Results: We found higher lymphocyte counts in PTSD patients than in healthy controls (2294.7 ± 678.0/μL vs 1817.2 ± 637.0/μL, P = 0.007) and a positive correlation between lymphocyte glucocorticoid receptor expression and the number of years that passed from the traumatic experience (rs = 0.43, P = 0.008). Lymphocyte glucocorticoid receptor expression positively correlated with serum cortisol concentration both in PTSD patients (r = 0.46, P = 0.006) and healthy controls (r = 0.46, P = 0.035). Conclusion: This study confirmed that the immune system was affected in the course of chronic PTSD. Our findings also indicated that the hypothalamic-pituitary-adrenal axis profile in PTSD was associated with the duration of the disorder. Due to the lack of power, greater sample sizes are needed to confirm the results of this study

Circulating Lymphocyte Subsets, Natural Killer Cell Cytotoxicity, and Components of Hypothalamic-Pituitary-Adrenal Axis in Croatian War Veterans with Posttraumatic Stress Disorder: Cross-Sectional Study

Aim: To determine peripheral blood lymphocyte subsets – T cells, helper T cells, cytotoxic T cells, B cells, and natural killer cells, natural killer cell cytotoxicity, serum cortisol concentration, and lymphocyte glucocorticoid receptor expression in Croatian combat veterans diagnosed with chronic posttraumatic stress disorder (PTSD); and to examine the relationship between the assessed parameters and the time passed since the traumatic experience. Methods: Well-characterized group of 38 PTSD patients was compared to a group of 24 healthy civilians. Simultaneous determination of lymphocyte subsets and the expression of intracellular glucocorticoid receptor was performed using three-color flow cytometry. Natural killer cell cytotoxicity was measured by 51Cr-release assay and the serum cortisol concentration was determined by radioimmunoassay. Results: We found higher lymphocyte counts in PTSD patients than in healthy controls (2294.7 ± 678.0/μL vs 1817.2 ± 637.0/μL, P = 0.007) and a positive correlation between lymphocyte glucocorticoid receptor expression and the number of years that passed from the traumatic experience (rs = 0.43, P = 0.008). Lymphocyte glucocorticoid receptor expression positively correlated with serum cortisol concentration both in PTSD patients (r = 0.46, P = 0.006) and healthy controls (r = 0.46, P = 0.035). Conclusion: This study confirmed that the immune system was affected in the course of chronic PTSD. Our findings also indicated that the hypothalamic-pituitary-adrenal axis profile in PTSD was associated with the duration of the disorder. Due to the lack of power, greater sample sizes are needed to confirm the results of this study

The Increased Type-1 and Type-2 Chemokine Levels in Children with Acute RSV Infection Alter the Development of Adaptive Immune Responses

Severe RSV infections and frequent recurrence could be related to the altered polarization of type-2/type-1 T cells. This increases the importance of determining distinctive chemokines and chemokine receptor profiles on memory T cells. We analyzed systemic adaptive T cell response in the acute (n=17) and convalescent phase (n=7) of RSV-infected children, in the acute (n=11) and convalescent phase (n=6) of children with other viral respiratory infections (adenovirus and influenza virus), and in healthy children (n=18). Expression of CCR4 and CXCR3 on effector-memory (TEM) and central-memory (TCM) T cells was compared between tested groups. Serum concentrations of specific chemokines were determined. High CXCL10 levels were detected in acutely infected children regardless of virus pathogen, whereas increased CCL17 production was RSV-specific. Higher percentages of CCR4+ CD4 TEM cells in acute RSV infection were accompanied with higher percentages of CXCR3+ CD8 TEM cells, whereas the development of long-lived memory CXCR3+ CD4 and CD8 TCM cells seems to be compromised, as only children with other viral infections had higher percentages in the convalescent phase. Presence of type-2 and type-1 adaptive antiviral immune response, together with insufficient development of long-lived type-1 T cell memory, could play an important role in RSV pathogenesis and reinfection

Expression of chemokine receptor CX3CR1 in infants with respiratory syncytial virus bronchiolitis

Respiratory syncytial virus (RSV) glycoprotein G mimics fractalkine, a CX(3)C chemokine, which mediates chemotaxis of leukocytes expressing its receptor, CX(3)CR1. The aim of this study was to examine the relationship between RSV infection and expression of perforin and IFN-gamma in CX(3)CR1-expressing peripheral blood CD8(+) T cells. Samples were collected from infants with RSV bronchiolitis, both in the acute and convalescence phase (n = 12), and from their age- and sex-matched healthy controls (n = 15). Perforin expression and IFN-gamma secretion in CX(3)CR1(+) CD8(+) T cells were assessed by four-color flow cytometry. The NF-kappaB p50 and p65 subunit levels were also determined as markers of RSV-induced inflammation. Study results showed perforin and CX(3)CR1 expression to be significantly lower in the convalescent phase of infected infants than in healthy controls. There was no significant difference in IFN-gamma secretion and NF-kappaB binding activity between two time-points in RSV-infected infants, or when compared with healthy controls. Infants with prolonged wheezing had lower acute-phase CX(3)CR1 levels in peripheral blood. These data indicate existence of an event persisting after acute RSV infection that is able to modulate effector functions of cytotoxic T cells, and also link disease severity with CX(3)CR1 expression