Activation Of Cellular Immune Response Research Articles

Neutralizing Antibodies in COVID-19 Serum from Tatarstan, Russia.

The severity of COVID-19 is a result of the complex interplay between various branches of the immune system. However, our understanding of the role of neutralizing antibodies and the activation of cellular immune response in COVID-19 pathogenesis remains limited. In this study, we investigated neutralizing antibodies in patients with mild, moderate, and severe COVID-19, analyzing their cross-reactivity with the Wuhan and Omicron variants. We also assessed the activation of the immune response by measuring serum cytokines in patients with mild, moderate, and severe COVID-19. Our findings suggest the early activation of neutralizing antibodies in moderate COVID-19 compared to mild cases. We also observed a strong correlation between the cross-reactivity of neutralizing antibodies to the Omicron and Wuhan variants and the severity of the disease. In addition, we found that Th1 lymphocyte activation was present in mild and moderate cases, while inflammasomes and Th17 lymphocytes were activated in severe COVID-19. In conclusion, our data indicate that the early activation of neutralizing antibodies is evident in moderate COVID-19, and there is a strong correlation between the cross-reactivity of neutralizing antibodies and the severity of the disease. Our findings suggest that the Th1 immune response may play a protective role, while inflammasome and Th17 activation may be involved in severe COVID-19.

Urgency and necessity of Epstein-Barr virus prophylactic vaccines.

Epstein-Barr virus (EBV), a γ-herpesvirus, is the first identified oncogenic virus, which establishes permanent infection in humans. EBV causes infectious mononucleosis and is also tightly linked to many malignant diseases. Various vaccine formulations underwent testing in different animals or in humans. However, none of them was able to prevent EBV infection and no vaccine has been approved to date. Current efforts focus on antigen selection, combination, and design to improve the efficacy of vaccines. EBV glycoproteins such as gH/gL, gp42, and gB show excellent immunogenicity in preclinical studies compared to the previously favored gp350 antigen. Combinations of multiple EBV proteins in various vaccine designs become more attractive approaches considering the complex life cycle and complicated infection mechanisms of EBV. Besides, rationally designed vaccines such as virus-like particles (VLPs) and protein scaffold-based vaccines elicited more potent immune responses than soluble antigens. In addition, humanized mice, rabbits, as well as nonhuman primates that can be infected by EBV significantly aid vaccine development. Innovative vaccine design approaches, including polymer-based nanoparticles, the development of effective adjuvants, and antibody-guided vaccine design, will further enhance the immunogenicity of vaccine candidates. In this review, we will summarize (i) the disease burden caused by EBV and the necessity of developing an EBV vaccine; (ii) previous EBV vaccine studies and available animal models; (iii) future trends of EBV vaccines, including activation of cellular immune responses, novel immunogen design, heterologous prime-boost approach, induction of mucosal immunity, application of nanoparticle delivery system, and modern adjuvant development.

Enhancement of tumor immunogenicity by the introduction of non- proteinogenic amino acid azetidine-2-carboxylic acid

ABSTRACT Despite the clinical success in the treatment of several types of cancers, the immune checkpoint inhibitors (ICIs) show limited response rates in cancers with low tumor mutational burden (TMB) and antigenicity. Here, we aim to enhance tumor antigenicity at the protein translation level by using non-proteinogenic amino acids (NPAs) that cause regional mistranslation and mutated proteins. We utilized proline analogue azetidine-2-carboxylic acid (AZA), which can be discharged into proline tRNA by prolyl-tRNA synthetase, leading to the generation of a proportion of mutated proteins with proline residues substituted with Aze in tumor cells undergoing active protein synthesis. To specifically produce mutated proteins in tumor cells, the anti-Cd44 antibody-coated liposome nanoparticles (NPs) were used to deliver Aze specifically into the breast cancer cells. The Aze delivered by NPs can be incorporated into proteins in the 4T1 tumor allografts in mice, resulting in the activation of cellular immune responses and hence the significant inhibition of the growth of 4T1 allografts and the pulmonary metastasis, eventually prolonging the survival of tumor-bearing mice. Interestingly, Aze increases the response of 4T1 breast cancer allografts to anti-PD1 antibody treatment, suggesting Aze is able to sensitize tumors to the ICIs treatment in the immunotherapy of tumors.

Molecular and biological characterization of an Asian-American isolate of Chikungunya virus

Chikungunya virus is an arthropod-transmitted virus that causes chikungunya fever, a disease characterized by severe muscle and joint pain. In 2013, the virus was introduced to the Americas and caused approximately 2.7 million cases of infection during the subsequent two years. The lack of knowledge regarding the biological behavior of the viral strains circulating during the outbreak motivated the characterization of an isolate from the Colombian outbreak, starting from analysis of the complete genome to the biological behavior in vitro. The full genome was retrieved using next-generation sequencing. The infective and replicative capacities were evaluated in HEK293T, Huh-7, and MRC-5 cell lines. The infection rates were determined by flow cytometry, and the cytopathic effect was assessed by a resazurin fluorescent metabolic assay. The viral yield was quantified using the virus plaque formation assay, while the viral proteins and genomic RNA kinetics were subsequently evaluated by western-blot and RT-qPCR. The COL7624 isolate clustered with other American and Caribbean sequences in the Asian American lineage. The T669A substitution in E2 protein distinguished it from other Colombian sequences reported in 2014. After 48 h post infection (hpi), the three cell lines analyzed reached infection percentages exceeding 65%, generating a high load of infectious viral progeny. The infection kinetics indicated that the replication peak of this CHIKV isolate is around 24 hpi, although gRNA is detectable in the culture supernatant from 4 hpi onwards. The infection caused the overexpression of interferon and pro-inflammatory cytokines, such as IL-1β, TNF-α, and IL-8. The COL7624 CHIKV isolate exhibited a high infective and replicative capacity as well as activation of cellular immune responses, similar to isolates belonging to the other genotypes.

Immunogenicity of Multiple Doses of pDNA Vaccines against SARS-CoV-2.

Since its identification in Wuhan, China, in December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), has resulted in 46 million cases and more than one million deaths worldwide, as of 30 October 2020. Limited data exist on the magnitude and durability of antibodies generated by natural infection with SARS-CoV-2 and whether they can provide long-lasting immunity from reinfection. Vaccination has proven the most effective measure for controlling and preventing pandemics and, thus, development of a vaccine against COVID-19 is a top priority. However, the doses required to induce effective, long-lasting antibody responses against SARS-CoV-2 remain undetermined. Here, we present the development of SARS-CoV-2 vaccine candidates encoding the viral spike (S) gene, generated using plasmid (p)DNA technology, and we demonstrate the eliciting of S-specific antibodies in mice after three and four doses. The magnitude of binding and neutralizing antibody responses with three doses of synthetic, codon-optimized, full-length S (S.opt.FL) vaccine is comparable to that generated after four doses, suggesting that three doses are sufficient to elicit robust immune responses. Conversely, four doses of S1.opt pDNA vaccine, containing the S globular head, are required to elicit high levels of neutralizing antibodies. Furthermore, the S.opt.FL pDNA vaccine induces the highest serum levels of interferon (IFN)-γ, a marker for activation of cellular immune responses. Overall, our data show that three doses of S.FL pDNA vaccine elicit potent neutralizing antibody responses, with preclinical data that support the immunogenicity of these COVID-19 vaccine candidates and provide justification for further translational studies.

Activation of cellular immune response in insect model host Galleria mellonella by fungal α-1,3-glucan.

Alpha-1,3-glucan, in addition to β-1,3-glucan, is an important polysaccharide component of fungal cell walls. It is reported for many fungal species, including human pathogenic genera: Aspergillus, Blastomyces, Coccidioides, Cryptococcus, Histoplasma and Pneumocystis, plant pathogens, e.g. Magnaporthe oryzae and entomopathogens, e.g. Metarhizium acridum. In human and plant pathogenic fungi, α-1,3-glucan is considered as a shield for the β-1,3-glucan layer preventing recognition of the pathogen by the host. However, its role in induction of immune response is not clear. In the present study, the cellular immune response of the greater wax moth Galleria mellonella to Aspergillus niger α-1,3-glucan was investigated for the first time. The changes detected in the total hemocyte count (THC) and differential hemocyte count (DHC), formation of hemocyte aggregates and changes in apolipophorin III localization indicated activation of G. mellonella cellular mechanisms in response to immunization with A. niger α-1,3-glucan. Our results, which have clearly demonstrated the response of the insect immune system to this fungal cell wall component, will help in understanding the α-1,3-glucan role in immune response against fungal pathogens not only in insects but also in mammals, including humans.

Combating viral contaminants in CHO cells by engineering innate immunity

Viral contamination in biopharmaceutical manufacturing can lead to shortages in the supply of critical therapeutics. To facilitate the protection of bioprocesses, we explored the basis for the susceptibility of CHO cells to RNA virus infection. Upon infection with certain ssRNA and dsRNA viruses, CHO cells fail to generate a significant interferon (IFN) response. Nonetheless, the downstream machinery for generating IFN responses and its antiviral activity is intact in these cells: treatment of cells with exogenously-added type I IFN or poly I:C prior to infection limited the cytopathic effect from Vesicular stomatitis virus (VSV), Encephalomyocarditis virus (EMCV), and Reovirus-3 virus (Reo-3) in a STAT1-dependent manner. To harness the intrinsic antiviral mechanism, we used RNA-Seq to identify two upstream repressors of STAT1: Gfi1 and Trim24. By knocking out these genes, the engineered CHO cells exhibited activation of cellular immune responses and increased resistance to the RNA viruses tested. Thus, omics-guided engineering of mammalian cell culture can be deployed to increase safety in biotherapeutic protein production among many other biomedical applications.

Vaccination with three tandem repeats of M2 extracellular domain fused to Leismania major HSP70 protects mice against influenza A virus challenge

Influenza viruses are globally important respiratory pathogens with high degree of morbidity and mortality during annual epidemics. Influenza A vaccination has been challenged due to genetic evolution. M2 protein is the surface antigen of the virus and facilitates virus entry into the host cells. N-terminal 24 amino acid residues that constitute the extracellular domain of M2 protein (M2e) show remarkable conservation among all subtypes of influenza A viruses. The aim of the present study was to investigate the effects of using HSP70 as an adjuvant fused to three tandem repeats of M2e (3M2e) to enhance the immune responses against influenza A challenge.The mice were immunized three times by intradermal inoculations of 3M2e alone or in combination with Alum adjuvant or in fused form to HSP70. The specific immune responses were evaluated by measuring the serum antibody titers, lymphocyte proliferation, as well as Th1 and Th2 cytokines.The results showed that, although 3M2e with no adjuvant could induce secretion of specific antibodies, significantly higher humoral immune responses were stimulated in combination with Alum adjuvant (p < 0.05). Moreover, analysis of specific immune responses revealed that the 3M2e-HSP70 chimer protein mainly stimulated IgG2a and IFN-γ responses indicating aTh1 bias which shows the ability of HSP as a powerful adjuvant for activation of cellular immune responses. This was supported by a higher IgG2a/IgG1 ratio, significantly increased IL-4 production and lymphocyte proliferation (P ˂ 0.001) compared with mice vaccinated with 3M2e alone or supplemented with Alum, suggesting a mixture of Th1 and Th2 type cellular immune response with a Th1 bias.The findings of this study indicated that 3M2e-HSP70 enhances humoral and cellular immune responses and improves immune protection against influenza challenge in mice. Thus, it has the potential to be used as a promising vaccine candidate.

Characterization of BIP protein of G. lamblia as a potential immunogen in a mouse infection model

Giardia lamblia is a protozoan parasite that causes one of the most common gastrointestinal diseases worldwide. To eliminate the parasite from the host intestine, it is necessary the activation of B-cell and T-cell dependent mechanisms. The knowledge about Giardia antigens that can stimulate the host immune response is limited. Recently, it has been described the Binding Immunoglobulin Protein (BIP) of G. lamblia (71kDa) as a potential immunogen. Additionally, our group has identified a highly immunogenic antigen (5G8 protein) of G. lamblia with a relative molecular mass of approximately 70kDa. There is some evidence suggesting that the 5G8 protein may activate both humoral and cellular immune responses. Based on these observations and preliminary mass spectrometry analyses, we hypothesized that the antigen 5G8 could be the BIP protein. In the present study, we characterize immunochemically the BIP protein of Giardia. Flow cytometric assays and western blotting were used to determine the expression profile of BIP and 5G8 antigens in Giardia trophozoites. The differences in expression profile indicated that BIP and 5G8 are not the same molecule. ELISA and Western blotting assays revealed that BIP protein was recognized by antibodies produced during G. lamblia infection in C3H/HeN mice. MTT assays did not reveal the activation of cellular immune response induced by BIP protein in vitro. In addition, we identified the potential B-cell and T-cell epitopes of G. lamblia BIP protein. This molecule is a conserved protein among Giardia strains and other pathogens. The complete immunological characterization of this antigen will contribute to a better understanding of the host–parasite interactions in Giardia infection.

Adjuvant use of the NKT cell agonist alpha-galactosylceramide leads to enhancement of M2-based DNA vaccine immunogenicity and protective immunity against influenza A virus.

DNA vaccines can induce both humoral and cellular immune responses in animals. However, DNA vaccines suffer from limited vaccine potency due to low immunogenicity. Therefore, different strategies are required for significant improvement of DNA vaccine efficacy such as inclusion of strong adjuvants. The aim of the present study was to investigate the effects of using α-Galactosylceramide (α-GalCer) as an adjuvant to enhance the immune responses induced by a DNA vaccine, encoding influenza A virus matrix protein 2 (M2), against influenza A challenge. BALB/c mice were immunized three times by intramuscular inoculations of DNA vaccine encoding M2 alone or in combination with α-GalCer adjuvant. The adjuvant effect was evaluated by measuring the serum antibody titers, using ELISA, lymphocyte proliferation, using MTT assay as well as Th1 (IFN-γ and IL-12) and Th2 (IL-4) cytokines. The results showed that co-administration of α-GalCer with the vaccine exert protective effects by influencing the magnitude and quality of humoral responses. Adjuvanted DNA-vaccinated mice revealed a higher IgG titer and IgG2a/IgG1 ratio than mice vaccinated with DNA alone. Furthermore, analysis of M2-specific responses revealed that the DNA vaccine triggered predominately IgG1 and IL-4 responses indicating a Th2 bias. The data also showed that α-GalCer is a potent adjuvant for activation of cellular immune responses to DNA vaccine. This was supported by a higher IgG2a/IgG1 ratio, significantly increased IFN-γ and IL-4 production and CD4+ proliferation, compared with mice receiving the DNA vaccine alone, suggesting a mixed Th1/Th2-type cellular immune response with a Th1 bias. The findings of this study indicate that α-GalCer has the potential to be used as a potent adjuvant for a DNA vaccine encoding M2, since it enhances humoral and cellular immune response and improves immune protection against influenza challenge in mice.

How serious are health impacts in one of the most polluted regions of Central Europe?

The long-term exposure to pollutants in ambient air is associated with higher mortality and occurrence of respiratory and cardiopulmonary diseases. The longitudinal cross-section study focuses on the associations between long-term exposures to carcinogenic and non-carcinogenic pollutants and the prevalence and incidence of such specific diseases including immunodeficiencies. The data on health status from industrial and non-industrial regions were obtained from health documentation for a 5-year period from 2007 to 2011 and represent the whole population living in polluted (1,249,323 inhabitants) and unpolluted (631,387 inhabitants) regions. The data on concentrations of PM10, PM2,5, NO2, SO2, benzene and benzo[a]pyrene were collected. The concentrations of pollutants were estimated from measured data by using dispersion models. The average population-weighted concentration of pollutants, which is representative for a defined geographic area and time period from 2007 to 2011, was calculated from the obtained data. The logistic regression and the Mantel-Haenszel χ2 test were used to determine the odds ratios (OR) and p-values for a linear trend. Moreover, the relative risks of mortality and morbidity to specific diseases were calculated according to theoretical dose-response association published by World Health Organization (WHO). The probability of incidence of chronic obstructive pulmonary disease and bronchial asthma is statistically significantly higher in the population living in the polluted region compared to the population living in the unpolluted region. The association between long-term exposure to pollutants and the prevalence of immunodeficiency with predominantly antibody defects (D80) was confirmed. The strongest association was found for exposures to particulate matter (PM2,5). The prevalence of immunodeficiency with predominantly antibody defects was also observed in both regions depending on the age of the population and statistically significant difference was only found in the group of adults (20 and over). These associations encourage the hypothesis, that the long-term exposure to PM2.5 might cause the activation of cellular immune response. Further research is needed to explore the correlative immunoregulatory mechanism linking PM2.5 (or other pollutants - SO2) and immune cells. Nowadays, it is also believed that these associations are important in the increase of incidence of immune inflammatory response which is proven risk factor for cardiovascular disease (atherosclerotic disease, coronary heart disease and sudden cardiac death). Positive association between long-term exposure and prevalence of bronchial asthma and chronic obstructive pulmonary disease might be skewed due to important socio-economic factors (especially smoking).

Comparative transcriptomic analysis of immune responses of the migratory locust, Locusta migratoria, to challenge by the fungal insect pathogen, Metarhizium acridum.

BackgroundThe migratory locust, Locusta migratoria manilensis, is an immensely destructive agricultural pest that forms a devastating and voracious gregarious phase. The fungal insect pathogen, Metarhizium acridum, is a specialized locust pathogen that has been used as a potent mycoinsecticide for locust control. Little, however, is known about locust immune tissue, i.e. fat body and hemocyte, responses to challenge by this fungus.MethodsRNA-seq (RNA sequencing) technology were applied to comparatively examine the different roles of locust fat body and hemocytes, the two major contributors to the insect immune response, in defense against M. acridum. According to the sequence identity to homologies of other species explored immune response genes, immune related unigenes were screened in all transcriptome wide range from locust and the differential expressed genes were identified in these two tissues, respectively.ResultsAnalysis of differentially expressed locust genes revealed 4660 and 138 up-regulated, and 1647 and 23 down-regulated transcripts in the fat body and hemocytes, respectively after inoculation with M. acridum spores. GO (Gene Ontology) enrichment analysis showed membrane biogenesis related proteins and effector proteins significantly differentially expressed in hemocytes, while the expression of energy metabolism and development related transcripts were enriched in the fat body after fungal infection. A total of 470 immune related unigenes were identified, including members of the three major insect immune pathways, i.e. Toll, Imd (immune deficiency) and JAK/STAT (janus kinase/signal transduction and activator of transcription). Of these, 58 and three were differentially expressed in the insect fat body or hemocytes after infection, respectively. Of differential expressed transcripts post challenge, 43 were found in both the fat body and hemocytes, including the LmLys4 lysozyme, representing a microbial cell wall targeting enzyme.ConclusionsThese data indicate that locust fat body and hemocytes adopt different strategies in response to M. acridum infection. Fat body gene expression after M. acridum challenge appears to function mainly through activation of innate immune related genes, energy metabolism and development related genes. Hemocyte responses attempt to limit fungal infection primarily through regulation of membrane related genes and activation of cellular immune responses and release of humoral immune factors.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-2089-9) contains supplementary material, which is available to authorized users.

Recruitment of PLANT U-BOX13 and the PI4Kβ1/β2 phosphatidylinositol-4 kinases by the small GTPase RabA4B plays important roles during salicylic acid-mediated plant defense signaling in Arabidopsis.

Protection against microbial pathogens involves the activation of cellular immune responses in eukaryotes, and this cellular immunity likely involves changes in subcellular membrane trafficking. In eukaryotes, members of the Rab GTPase family of small monomeric regulatory GTPases play prominent roles in the regulation of membrane trafficking. We previously showed that RabA4B is recruited to vesicles that emerge from trans-Golgi network (TGN) compartments and regulates polarized membrane trafficking in plant cells. As part of this regulation, RabA4B recruits the closely related phosphatidylinositol 4-kinase (PI4K) PI4Kβ1 and PI4Kβ2 lipid kinases. Here, we identify a second Arabidopsis thaliana RabA4B-interacting protein, PLANT U-BOX13 (PUB13), which has recently been identified to play important roles in salicylic acid (SA)-mediated defense signaling. We show that PUB13 interacts with RabA4B through N-terminal domains and with phosphatidylinositol 4-phosphate (PI-4P) through a C-terminal armadillo domain. Furthermore, we demonstrate that a functional fluorescent PUB13 fusion protein (YFP-PUB13) localizes to TGN and Golgi compartments and that PUB13, PI4Kβ1, and PI4Kβ2 are negative regulators of SA-mediated induction of pathogenesis-related gene expression. Taken together, these results highlight a role for RabA4B and PI-4P in SA-dependent defense responses.

Association between -173 G/C polymorphism of MIF and the susceptibility to develop lepromatous leprosy in mestizo patients from western Mexico

Association between -173 G/C polymorphism of MIF and the susceptibility to develop lepromatous leprosy in mestizo patients from western Mexico

Bridging autoantibodies and arthritis: the role of Fc receptors.

Autoantibodies represent a hallmark of Rheumatoid arthritis (RA), which is a chronic inflammatory autoimmune disease characterized by inflammation and damage in the joints. Anti-Citrullinated Protein Antibodies (ACPA) are the most prominent autoantibodies present in RA patients. These autoantibodies have been intensively investigated during the last 20years due to their diagnostic and predictive value. Furthermore, they are believed to be involved in mediating the damage associated with RA. Antibodies of the IgG isotype interact with the immune system via Fcγ receptors expressed on immune cells as well as nonimmune cells. These receptors, therefore, form the bridge between Fcγ receptor-positive cells and antibodies complexed to antigen allowing the modulation and activation of cellular immune responses that are involved in immune defense against invading microorganisms. However, in case triggered by antibodies against self-antigens, they can also play a pivotal role in the induction and perpetuation of autoimmune diseases such as RA. Mouse models have been indispensably important for understanding the role of Fcγ receptors in the development of arthritis. Here we discuss the contribution of autoantibodies to the pathogenesis of arthritis in preclinical animal models, as well as RA, in relation to their interaction with the different (immune inhibitory and activating) Fcγ receptors.

Phosphoinositide 3-kinase (PI3K) as a New Therapeutic Target for Rheumatoid Arthritis

Dysregulated activation of immune and synovial cells and their reciprocal action play a key role in the pathogenesis of rheumatoid arthritis (RA). Various signal transduction molecules regulate cellular responses and small molecular inhibitors targeting the signal molecules, such as Janus kinase (JAK) and spleen tyrosine kinase (Syk) inhibitors, which have been developed for treating RA. Phosphoinositide 3-kinase (PI3K) is one of the signal molecules, which regulates innate and adaptive immune systems and is over-expressed in RA. PI3Ks phosphorylate phosphoinositide-4,5- bisphosphate (PI-4,5-P2) generates phosphoinositide-3,4,5- triphosphate (PI-3,4,5-P3) at the cell membrane. PI3Ks are divided into class I, II and III. Two catalytic subunits, p110γ and p110δ of PI3K, modulate cellular development, differentiation, proliferation, migration, cytokine synthesis and antibody production in both innate and adaptive immune systems. In RA synovium and synovial fibroblasts, the expression of p110γ and p110δ is increased, and their upregulation results in the abnormal activation of cellular immune responses. In preclinical animal models for RA, genetic deletion of p110γ and p110δ and selective inhibitors decrease the clinical arthritis score, synovial inflammation, cellular infiltration, bone and cartilage erosion and osteoclast activity. There is a synergistic effect for controlling arthritis by dual inhibition of PI3Kγ and PI3Kδ. Through reviewing the function of PI3K in the immune system and the effect of PI3K inhibition in preclinical arthritis animal models, we can expect the PI3K inhibition as a new therapeutic target for treatment of RA.

Positive inductive effect of IL-18 on virus-specific immune responses induced by PRRSV-GP5 DNA vaccine in swine

Two DNA vaccines encoding the envelope protein GP5 of porcine reproductive and respiratory syndrome virus (PRRSV) alone (pEGFP-GP5) and co-encoding GP5 and swine interleukin-18 (IL-18) proteins (pEGFP-IL18-GP5), were constructed and comparatively evaluated for their abilities to induce humoral and cellular responses in piglets. Experimental results showed that among all vaccinated groups, the live PRRSV vaccine elicited the highest titre of serum neutralizing antibody and the strongest cell-mediated immune responses, which means that the live PRRSV vaccine is still the first option for the vaccination against PRRSV. Moreover, the piglets inoculated with pEGFP-IL18-GP5 developed significantly higher IFN-γ production response, significantly increased percentages of CD4+ and CD8+ T-lymphocytes and significantly higher specific T-lymphocyte proliferation response than the pEGFP-GP5 inoculated pigs (P<0.05). These results demonstrated the positive inductive effect of IL-18 on the activation of cellular immune responses in swines. Therefore, in order to develop a new type vaccine for PRRS prevention and control, co-encoding of GP5 and IL-18 proteins may be a good choice.

HIV-1 Vpu Interference with Innate Cell-mediated Immune Mechanisms

The HIV-1 accessory protein Vpu is emerging as a viral factor with a range of activities devoted to counteracting host innate immunity. Here, we review recent findings concerning the role of Vpu in hampering activation of cellular immune responses mediated by CD1d-restricted invariant natural killer T (iNKT) cells and natural killer (NK) cells. The two key findings are that Vpu interferes with CD1d expression and antigen presentation, and also with expression of the NK cell activation ligand NK-T and B cell antigen (NTB-A). Both these activities are mechanistically distinct from CD4 and Tetherin (BST-2) down-modulation. We summarize the mechanistic insights gained into Vpu interference with CD1d and NTB-A, as well as important challenges going forward, and discuss these mechanisms in the context of the role that iNKT and NK cells play in HIV-1 immunity and immunopathogenesis.

Phosphoinositide 3-kinase (PI3K)

Dysregulated activation of immune and synovial cells and their reciprocal action play a key role in the pathogenesis of rheumatoid arthritis (RA). Various signal transduction molecules regulate cellular responses and small molecular inhibitors targeting the signal molecules, such as Janus kinase (JAK) and spleen tyrosine kinase (Syk) inhibitors, which have been developed for treating RA. Phosphoinositide 3-kinase (PI3K) is one of the signal molecules, which regulates innate and adaptive immune systems and is over-expressed in RA. PI3Ks phosphorylate phosphoinositide-4,5- bisphosphate (PI-4,5-P2) generates phosphoinositide-3,4,5- triphosphate (PI-3,4,5-P3) at the cell membrane. PI3Ks are divided into class I, II and III. Two catalytic subunits, p110 γ and p110δ of PI3K, modulate cellular development, differentiation, proliferation, migration, cytokine synthesis and antibody production in both innate and adaptive immune systems. In RA synovium and synovial fibroblasts, the expression of p110γ and p110δ is increased, and their up-regulation results in the abnormal activation of cellular immune responses. In preclinical animal models for RA, genetic deletion of p110γ and p110δ and selective inhibitors decrease the clinical arthritis score, synovial inflammation, cellular infiltration, bone and cartilage erosion and osteoclast activity. There is a synergistic effect for controlling arthritis by dual inhibition of PI3Kγ and PI3Kδ. Through reviewing the function of PI3K in the immune system and the effect of PI3K inhibition in preclinical arthritis animal models, we can expect the PI3K inhibition as a new therapeutic target for treatment of RA.

Evaluation of Serum and Urinary Levels of some Pteridine Pathway Components in Healthy Turkish Children

Abstract Neopterin, as a non-conjugated pteridine, is synthesized from guanosine triphosphate and its production is upregulated upon the activation of cellular immune response. Alterations of pteridines in body fluids are known to correlate well with existing diseases and stages, prognosis, clinical outcomes and survival data. It is of advantage to have a pteridine database of healthy volunteers to determine normal values. Thereby, especially in children there is no detailed study on pteridine levels. The aim of this study is to initiate the establishment of pteridine database of healthy children in our country. Serum neopterin levels were analysed by enzyme-linked immunosorbent assay. Urinary neopterin and biopterin levels and serum kynurenine, tryptophan levels and kynurenine/tryptophan ratio as an estimate of tryptophan breakdown were assessed with high-pressure liquid chromatography in serum and urine samples of 55 children aged between 3 months and 10 years. The results were evaluated within the subgroups of different ages and sex. Pteridine pathway components were found to be higher in children compared to adults. Higher levels of pteridine pathway components observed within the first years of life may reflect the rapid maturation of the immune system, and environmental adaptation and/or insufficiency of defence systems. On the other hand, it may also relate to a higher frequency of infections not (yet) manifested clinically.