T-cell immunity is critical for survival of hosts infected with Toxoplasma gondii. Among the cells in the T-cell population, CD8(+) T cells are considered the major effector cells against this parasite. It is believed that CD4(+) T cells may be crucial for induction of the CD8(+)-T-cell response against T. gondii. ...

The gE glycoprotein of varicella zoster virus (VZV) is involved with cell entry and it is the most abundant glycoprotein produced in VZV-infected cells. It is also the first glycoprotein to be recognized by the immune system and induces neutralizing antibodies and cellular immunity. We have shown previously that immunization ...

Can self-specific T cells that have escaped intrathymic deletion be exploited to generate antitumor immunity? To determine whether antitumor immunity to a self-Ag for which central tolerance exists can be generated, a mouse model is used in which a fragment of the influenza nucleoprotein (NP) is expressed as a transgene ...

Viral persistence following infection with invasive strains of lymphocytic choriomeningitis virus (LCMV) can be achieved by selective down-regulation of virus-specific T lymphocytes. High viral burden in the onset of infection drives responding cells into functional unresponsiveness (anergy) that can be followed by their physical elimination. In this report, we studied ...

It is known that both animal and human retroviruses typically cause immunosuppression in their respective hosts, but the mechanisms by which this occurs are poorly understood. The present study uses Friend virus (FV) infections of mice as a model to determine how major histocompatibility complex (MHC) genes influence immunosuppression. Previously, ...

There is mounting evidence suggesting that infection with respiratory syncytial virus (RSV) in early life increases the risk of developing reactive airway disease (RAD) later in childhood. A recent prospective study demonstrated that children hospitalized with RSV bronchiolitis in infancy face a significantly increased risk of recurrent wheezing and allergy ...

Differential cytokine production by T cells plays an important role in regulating the nature of an immune response. In the rat, Brown-Norway (BN) and Lewis (LEW) strains differ markedly in their susceptibility to develop either type 1 or type 2-mediated autoimmune manifestations. BN rats are susceptible to type 2-dependent systemic ...

Heat shock proteins loaded with viral peptides were shown to induce a CD8+ T cell response and confer protective immunity against challenge with herpes simplex virus (HSV). The delivery system consisted of recombinant human hsp70 coupled to the peptide SSIEFARL, which is the immunodominant peptide epitope, recognized by HSV specific ...

Immune containment of measles virus (MV) infection has long been a focus of interest for investigators. An emerging theme is that MV immunity is conferred by appropriately polarized antiviral CD4+ and CD8+ T cell populations. Recent technological advances permit the analysis of the composition and dynamics of these CD4+ and ...

Cytomegalovirus (CMV) causes high morbidity and mortality in immunocompromised patients. The host immune response to CMV comprises specific and nonspecific cellular and humoral responses, but current knowledge supports a protective role only for cell-mediated immune responses. Although complete CMV eradication is unusual even in immunocompetent hosts, its morbidity can be ...

Viral bronchiolitis is the most common cause of hospitalization in infants under 6 months of age, and 70% of all cases of bronchiolitis are caused by respiratory syncytial virus (RSV). Early RSV infection is associated with respiratory problems such as asthma and wheezing later in life. RSV infection is usually ...

CD8 T cells respond to viral infections but also participate in defense against bacterial and protozoal infections. In the last few years, as new methods to accurately quantify and characterize pathogen-specific CD8 T cells have become available, our understanding of in vivo T cell responses has increased dramatically. Pathogen-specific T ...

B16F10 melanoma is a tumor derived from C57BL/6 mice that has been found to be poorly immunogenic and highly aggressive. Here we have shown that vaccination of mice with irradiated B16F10 cells followed by treatment with a combination of staphylococcal enterotoxins A and B (SEA/SEB) leads to significant and specific ...

The presence and phenotype of apoptotic lymphocytes was studied in spleen cell suspensions taken from CB6F1 mice infected with Plasmodium chabaudi chabaudi AS. High levels of apoptotic cells were found, associated with high parasitaemias and splenomegaly. This was also accompanied by expansion and disarray of spleen white pulp. Apoptosis levels ...

There is now compelling evidence that CD4(+) T cells that specialize in the suppression of immune responses play a key role in the control of immune pathology. Recently, there have been a number of reports that have provided information on the generation of CD4(+) regulatory T cells in the thymus ...

Killed or inactivated vaccines targeting intracellular bacterial and protozoal pathogens are notoriously ineffective at generating protective immunity. For example, vaccination with heat-killed Listeria monocytogenes (HKLM) is not protective, although infection with live L. monocytogenes induces long-lived, CD8 T cell-mediated immunity. We demonstrate that HKLM immunization primes memory CD8 T lymphocyte ...

Regional differences in immune responsiveness have been studied by comparing the frequency of cytokine producing T cells in healthy African children and adults and their age-matched European counterparts. By use of flow cytometry for the intracellular detection of cytokines an overall expansion of CD4+ and CD8+ T cells producing the ...

BACKGROUND: Immunostimulatory DNA sequences (ISS) activate the innate immune system to generate antiviral cytokines, such as IFN-gamma. OBJECTIVE: This study investigated whether ISS could reduce viral load, mucus secretion, airway inflammation, and airway hyperreactivity to methacholine in a mouse model of respiratory syncytial virus (RSV) infection. METHODS: Mice were pretreated ...

Neonates are highly susceptible to diseases and display biased type 2 immune responses, although no skewing to type 2 cytokines has been reported. In view of the emerging importance of IL-13 in type 2 inflammatory responses and clinical allergy, we analyzed IL-13 production by neonatal T cells. We found that, ...

Immunization of mice with live bradyzoites of a low-virulent Beverley strain of Toxoplasma gondii has been shown to increase CD8+ T-cell mediated immunity against a highly virulent RH strain. We found that preimmunization with an RH homogenate further enhanced this immunity. Using this model, we investigated the mechanism of CD8+ ...

It has long been recognized that some viral infections result in generalized immune suppression. In acute infections, this period of suppressed immunity is relatively short. However, chronic infections associated with a prolonged period of immune suppression present far greater risks. Here, we examined the role of CD8 T cell responses ...

The purpose of this study was to identify the cell populations involved in recovery from oral infections with Candida albicans. Monoclonal antibodies specific for CD4+ cells, CD8+ cells, and polymorphonuclear leukocytes were used to deplete BALB/c and CBA/CaH mice of the relevant cell populations in systemic circulation. Monocytes were inactivated ...

We have reported that macrophages expressing heat-shock protein 65 play an essential role in protection of mice infected with Plasmodium yoelii. In this study, we investigated the function and expression mechanism of HSP65 in macrophages of mice infected with P. yoelii. C57BL/6 (B6) mice are susceptible to infection with the ...

We identified specialized B helper and tissue inflammatory CD4(+) T cell subsets that developed concurrently from common naïve precursors during the primary immune response. These separable populations were distinguishable by their expression of adhesion and chemoattractant receptors that directed their homing to the appropriate effector sites in vivo and also ...

West Nile virus (WNV) is a vectorborne pathogen that induces brain inflammation and death. Recently, confirmed cases of infection and deaths have occurred in the United States Mid-Atlantic region. In this study, a DNA vaccine encoding the WNV capsid protein was constructed, and the in vivo immune responses generated were ...

Immunopathology that is caused by re-infection with Chlamydia trachomatis is very common in humans despite regular responses to multiple, often conserved, antibody and T cell epitopes. Recurrent mutations that disrupt T cell epitopes in the major outer membrane protein in clinical isolates and the reduced transcription of HLA genes by ...

The effects of self-hypnosis training on immune function and mood were examined in medical students at exam time. Hypnosis involved relaxation and imagery directed at improved immune function and increased energy, alertness and concentration. Hypotheses were made about activated and withdrawn personality differences. Eight high and eight low hypnotically susceptible ...

OBJECTIVE: To construct a eukaryotic expression system with pcDNA3-PfCSP/Hela for the Circumsporozoite protein (CSP) gene of Plasmodium falciparum (P. falciparum), to observe the immune responses in BALB/c mice induced by the expressed proteins. METHODS: The recombinant plasmid pcDNA3-PfCSP was transformed into the Hela cell line. The expressed protein was isolated ...

Subdominant CD8(+) T-cell responses contribute to control of several viral infections and to vaccine-induced immunity. Here, using the lymphocytic choriomeningitis virus model, we demonstrate that subdominant epitopes can be more reliably identified by DNA immunization than by other methods, permitting the identification, in the virus nucleoprotein, of two overlapping subdominant ...

There is a strong link between virus specific CD8 T-cell function and the efficiency of regulatory CD4 helper T cells. Controlling viraemia in HIV-1-infected individuals requires the maintenance of strong CD4 and CD8 T-cell responses. These responses should be elicited by prophylactic vaccination and by postexposure immunotherapy. This review will ...

Experiments designed to distinguish virus-specific from non-virus-specific T cells showed that bystander T cells underwent apoptosis and substantial attrition in the wake of a strong T-cell response. Memory CD8 T cells (CD8(+) CD44(hi)) were most affected. During acute viral infection, transgenic T cells that were clearly defined as non-virus specific ...

Engineering gene therapy vectors to modulate the immune response is an important goal. In this regard, costimulation of T cells is a critical determinant in immune activation. The costimulatory molecule CD40, expressed on antigen-presenting cells, is thought to interact with CD40 ligand (CD40L) expressed on activated CD4(+) or CD8(+) T ...

Vertebrates express three cytokine-inducible proteasome subunits that are incorporated in the place of their constitutively synthesized counterparts. There is increasing evidence that the set of peptides generated by proteasomes containing these subunits (immunoproteasomes) differs from that produced by standard proteasomes. In this study, we use mice lacking one of the ...

Mycobacterial infection is associated with granuloma formation in which the presence of apoptosis has been recognized. The role of CD4+ T and CD8+ T cells in host protection against mycobacterial infections has been demonstrated. Previous studies, however, have shown that CD8+ T cells have a limited role in host defense ...

The successful induction of T cell-mediated protective immunity against poorly immunogenic malignancies remains a major challenge for cancer immunotherapy. Here, we demonstrate that the induction of tumor-protective immunity by IL-12 in a murine neuroblastoma model depends entirely on the CXC chemokine IFN-gamma-inducible protein 10 (IP-10). This was established by in ...

We have recently described a novel population of CD8+ phagocytes that are strongly recruited to focal ischemic lesions of the rat brain but absent from axotomized central fiber tracts. To assess the relative contribution of infiltrating macrophages and resident microglia to the CD8+ phagocyte response, we selectively depleted peripheral macrophages ...

SH2D1A, which encodes signaling lymphocyte activation molecule (SLAM)-associated protein (SAP), is altered in patients with X-linked lymphoproliferative disease (XLP), a primary immunodeficiency. SAP-deficient mice infected with lymphocytic choriomeningitis virus had greatly increased numbers of CD8+ and CD4+ interferon-gamma-producing spleen and liver cells compared to wild-type mice. The immune responses of ...

BACKGROUND: Surgical trauma and anesthesia are known to cause transient postoperative suppression of the immune system. In randomized controlled trials, it has been shown that laparoscopic colorectal resections have short-term benefits not observed with conventional colorectal resections. We hypothesized that these benefits were due to the reduction in surgical trauma, ...

The present study demonstrates that the quality of the virus-specific CD8(+) T cell responses, as detected by both enzyme-linked immunospot assay and specific MHC-peptide tetramers, changed in relation to the different disease activity in chronically hepatitis C virus-infected patients. Indeed, both the serum alanine transaminase and the hepatic flogosis levels ...

Major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocytes (CTLs) clear respiratory tract infections caused by the pneumovirus respiratory syncytial virus (RSV) and also mediate vaccine-induced pulmonary injury. Herein we examined the mechanism for RSV-induced MHC class I presentation. Like infectious viruses, conditioned medium from RSV-infected cells (RSV-CM) induces naive ...

In this study, we evaluated the effects of respiratory syncytial virus (RSV) infection on nitric oxide (NO) production in human airway epithelial cells. In addition, we evaluated whether T-helper type 1 (Th1)- and Th2-type cytokines modulate the release of NO in response to RSV infection. To do this, we infected ...

The poor correlation between cellular immunity to respiratory virus infections and the numbers of memory CD8(+) T cells in the secondary lymphoid organs suggests that there may be additional reservoirs of T cell memory to this class of infection. Here we identify a substantial population of Ag-specific T cells in ...

The first naturally processed peptide synthesized by a virus and recognized by classical CD8(+) T cells in association with the RT1.A(l) major histocompatibility complex class I molecule of the Lewis rat is reported. Borna disease virus-specific CD8(+) T cells recognize syngeneic target cells pulsed with peptides extracted from Borna disease ...

Recent observations have indicated that viral persistence and tumor spreading could occur because of effector function-defective CD8(+) T cells. Although chronic exposure to Ag, lack of CD4 help, and epitope dominance are suggested to interfere with CTL differentiation, mechanisms underlying the defective effector function remain obscure. We demonstrate in this ...

The respiratory syncytial virus (RSV)-specific frequencies and cytokine expression patterns of acute and memory CD4(+) T cells from RSV strain-A- and strain-B-infected BALB/c mice were determined following restimulation with a panel of 14 predicted RSV I-E(d) peptides from NSP-2, M, SH, F, and L proteins. Ten of fourteen peptides stimulated ...

The strong macrophage response occurring during Wallerian degeneration in the peripheral but not central nervous system has been implicated in tissue remodeling and growth factor production as key requirements for successful axonal regeneration. We have previously identified a population of CD8+ phagocytes in ischemic brain lesions that differed in its ...

Understanding the interactions between a host and a pathogen relies crucially on quantitative measurements of immune responses. Until recently, measurements of the levels of cellular immune responses, i.e. those mediated by CD4+ and CD8+ T lymphocytes have depended largely on culture in vitro and subsequent measurement of specific functions (such ...

Functions of macrophage are known to be altered by acute infection with respiratory syncytial virus (RSV). However, it is unknown whether the persistent presence and expression of the RSV genome have any effect on the functions of these cells. We used a murine macrophage-like cell line (P388D1) persistently infected with ...

Respiratory virus infections, such as those caused by influenza and parainfluenza viruses, are a major cause of morbidity and mortality worldwide. Current vaccines against these pathogens rely on the induction of humoral immune responses that target viral coat proteins. Although this type of immunity provides solid protection against homologous virus ...

Contact hypersensitivity (CHS) is a T cell-mediated immune response to cutaneous sensitization and subsequent challenge with haptens such as dinitrofluorobenzene and oxazolone. Many aspects concerning the development and regulation of CHS remain unknown. Using CHS as a model of T cell-mediated immune responses to antigens deposited in the skin we ...