Harlan P. Jones

Psychological Stress and the Cutaneous Immune Response: Roles of the HPA Axis and the Sympathetic Nervous System in Atopic Dermatitis and Psoriasis

Psychological stress, an evolutionary adaptation to the fight-or-flight response, triggers a number of physiological responses that can be deleterious under some circumstances. Stress signals activate the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic nervous system. Elements derived from those systems (e.g., cortisol, catecholamines and neuropeptides) can impact the immune system and possible disease states. Skin provides a first line of defense against many environmental insults. A number of investigations have indicated that the skin is especially sensitive to psychological stress, and experimental evidence shows that the cutaneous innate and adaptive immune systems are affected by stressors. For example, psychological stress has been shown to reduce recovery time of the stratum corneum barrier after its removal (innate immunity) and alters antigen presentation by epidermal Langerhans cells (adaptive immunity). Moreover, psychological stress may trigger or exacerbate immune mediated dermatological disorders. Understanding how the activity of the psyche-nervous -immune system axis impinges on skin diseases may facilitate coordinated treatment strategies between dermatologists and psychiatrists. Herein, we will review the roles of the HPA axis and the sympathetic nervous system on the cutaneous immune response. We will selectively highlight how the interplay between psychological stress and the immune system affects atopic dermatitis and psoriasis.

Depletion of CD8+ T Cells Exacerbates CD4+ Th Cell-Associated Inflammatory Lesions During Murine Mycoplasma Respiratory Disease

Mycoplasma infection is a leading cause of pneumonia worldwide and can lead to other respiratory complications. A component of mycoplasma respiratory diseases is immunopathologic, suggesting that lymphocyte activation is a key event in the progression of these chronic inflammatory diseases. The present study delineates the changes in T cell populations and their activation after mycoplasma infection and determines their association with the pathogenesis of murine Mycoplasma respiratory disease, due to Mycoplasma pulmonis infection. Increases in T cell population numbers in lungs and lower respiratory lymph nodes were associated with the development of mycoplasma respiratory disease. Although both pulmonary Th and CD8+ T cells increased after mycoplasma infection, there was a preferential expansion of Th cells. Mycoplasma-specific Th2 responses were dominant in lower respiratory lymph nodes, while Th1 responses predominated in spleen. However, both mycoplasma-specific Th1 and Th2 cytokine (IL-4 and IFN-γ) responses were present in the lungs, with Th1 cell activation as a major component of the pulmonary Th cell response. Although a smaller component of the T cell response, mycoplasma-specific CD8+ T cells were also a significant component of pulmonary lymphoid responses. In vivo depletion of CD8+ T cells resulted in dramatically more severe pulmonary disease, while depletion of CD4+ T cells reduced its severity, but there was no change in mycoplasma numbers in lungs after cell depletion. Thus, mycoplasma-specific Th1 and CD8+ T cell activation in the lung plays a critical regulatory role in development of immunopathologic reactions in Mycoplasma respiratory disease.

The Pulmonary Environment Promotes Th2 Cell Responses After Nasal-Pulmonary Immunization with Antigen Alone, but Th1 Responses Are Induced During Instances of Intense Immune Stimulation

The purpose of this study was to determine the nature of the CD4+ Th cell responses induced after nasal-pulmonary immunization, especially those coinciding with previously described pulmonary inflammation associated with the use of the mucosal adjuvant, cholera toxin (CT). The major T cell population in the lungs of naive mice was CD4+, and these cells were shown to be predominantly of Th2 type as in vitro polyclonal stimulation resulted in IL-4, but not IFN-γ, production. After nasal immunization with influenza Ag alone, Th2 cytokine mRNA (IL-4 and IL-5) levels were increased, whereas there was no change in Th1 cytokine (IL-2 and IFN-γ) mRNA expression. The use of the mucosal adjuvant, CT, markedly enhanced pulmonary Th2-type responses; however, there was also a Th1 component to the T cell response. Using in vitro Ag stimulation of pulmonary lymphocytes, influenza virus-specific cytokine production correlated with the mRNA cytokine results. Furthermore, there was a large increase in CD4+ Th cell numbers in lungs after nasal immunization using CT, correlating with the pulmonary inflammatory infiltrate previously described. Coincidentally, both macrophage-inflammatory protein-1α (MIP-1α) and MIP-1β mRNA expression increased in the lungs after immunization with Ag plus CT, while only MIP-1β expression increased when mice were given influenza Ag alone. Our study suggests a mechanism to foster Th1 cell recruitment into the lung, which may impact on pulmonary immune responses. Thus, while Th2 cell responses may be prevalent in modulating mucosal immunity in the lungs, Th1 cell responses contribute to pulmonary defenses during instances of intense immune stimulation.

Immunoglobulin A (IgA) responses and IgE-associated inflammation along the respiratory tract after mucosal but not systemic immunization.

ABSTRACT The purpose of the present study was to determine the extent of immunologic responses, particularly immunopathologic responses, within the upper and lower respiratory tracts after intranasal immunization using the mucosal adjuvant cholera toxin (CT). BALB/c mice were nasally immunized with influenza virus vaccine combined with CT. The inclusion of the mucosal adjuvant CT clearly enhanced generation of antibody responses in both the nasal passages and lungs. After nasal immunization, antigen-specific immunoglobulin A (IgA) antibody-forming cells dominated antibody responses throughout the respiratory tract. However, IgG responses were significant in lungs but not in nasal passages. Furthermore, parenteral immunization did not enhance humoral immunity in the upper respiratory tract even after a nasal challenge, whereas extrapulmonary lymphoid responses enhanced responses in the lung. After nasal immunization, inflammatory reactions, characterized by mononuclear cell infiltration, developed within the lungs of mice but not in nasal passages. Lowering dosages of CT reduced, but did not eliminate, these adverse reactions without compromising adjuvancy. Serum IgE responses were also enhanced in a dose-dependent manner by inclusion of CT. In summary, there are differences in the generation of humoral immunity between the upper respiratory tract and the lung. As the upper respiratory tract is in a separate compartment of the immune system from that stimulated by parenteral immunization, nasal immunization is an optimal approach to generate immunity throughout the respiratory tract. Despite the promise of nasal immunization, there is also the potential to develop adverse immunopathologic reactions characterized by pulmonary airway inflammation and IgE production.

Co-expression of granulocyte-macrophage colony-stimulating factor with antigen enhances humoral and tumor immunity after DNA vaccination

Granulocyte-macrophage colony-stimulating factor (GM-CSF) was used to enhance humoral and tumor immunity resulting from DNA immunization. The genes encoding GM-CSF and antigen were cloned onto the same plasmid backbone, but separate promoters drove expression of each gene. beta-Galactosidase was used as the model antigen to generate antibody responses while the human tumor antigen, MAGE-1, was used to monitor tumor resistance. Immunization with a DNA vaccine co-expressing GM-CSF and beta-gal resulted in higher antigen-specific IgG responses than immunization with antigen encoding plasmid alone or co-inoculated with GM-CSF expressing plasmid. Similarly, DNA vaccines expressing both MAGE-1 antigen and GM-CSF were more effective in protecting against B16-MAGE-1 melanoma. However, both GM-CSF co-expressing DNA vaccines and co-inoculation with plasmids encoding the cytokine or antigen enhanced the generation antigen-specific IFN-gamma and IL-6 responses. These results demonstrate that co-expressing both GM-CSF and antigen on a DNA vaccine enhances humoral and tumor immune responses.

Epinephrine-primed murine bone marrow-derived dendritic cells facilitate production of IL-17A and IL-4 but not IFN-γ by CD4+ T cells

Sympathetic activation leading to the release of epinephrine and norepinephrine, is known as an important regulatory circuit related to immune-mediated diseases. However, questions still remain on the behavior of antigen presenting cells (APC) dictated by stress-induced sympathetic neurotransmitters. The purpose of this study was to examine the fate of bone marrow-derived dendritic cell (BMDC)-associated influences on resting CD4(+) T cell activation. We hypothesize that pre-exposure of dendritic cells (DCs) can modify the intensity of cytokine production, leading to preference in resting CD4(+) T cell activation. BMDCs were pre-treated with epinephrine for 2h followed by subsequent treatment of lipopolysaccharide (LPS). Subsequently, BMDCs were cocultured with purified CD4(+) T cells from mouse spleen in the absence or presence of anti-CD3 stimulation in epinephrine-free media. Epinephrine pre-treatment enhanced surface expression of MHCII, CD80 and CD86. Quantitative RT-PCR showed that epinephrine pre-treatment induced a significant transcriptional decrease of IL-12p40 and a significant increase of IL-12p35 and IL-23p19. In addition, β2-adrenergic-blockade was shown to reverse these effects. Epinephrine pre-treatment also induced a significant decrease of IL-12p70 and a significant increase of IL-23 and IL-10 cytokine production. Importantly, these changes corresponded with increased IL-4 and IL-17A, but not IFN-g cytokine production by CD4(+) T cells in a b2-adrenergic receptor-dependent manner. These results suggest that exposure to stress-derived epinephrine dictates dendritic cells to generate a dominant Th2/Th17 phenotype in the context of subsequent exposure to a pathogenic stimulus.

The Upper and Lower Respiratory Tracts Differ in Their Requirement of IFN-γ and IL-4 in Controlling Respiratory Mycoplasma Infection and Disease

The purpose of this study is to evaluate the significance of IFN-γ and IL-4 production in controlling mycoplasma infection and the pathogenesis of disease in the upper and lower respiratory tract. By using IFN-γ knockout and IL-4 knockout BALB/c mice, we were able to study the contribution of these cytokines in the development of pathogenesis and/or protection in response to mycoplasma respiratory infection, in both the upper and lower respiratory tracts. The loss of either IFN-γ or IL-4 does not affect disease pathogenesis or mycoplasma organism numbers in the upper respiratory tract. However, in the absence of IL-4, the nasal passages developed a compensatory immune response, characterized by higher numbers of macrophages and CD8+ T cells, which may be masking detrimental effects due to IL-4 deficiency. This is in contrast to the lower respiratory tract, where the loss of IFN-γ, but not IL-4, leads to higher mycoplasma numbers and increased disease severity. The loss of IFN-γ impacted the innate immune system’s ability to effectively clear mycoplasma, as the number of organisms was higher by day 3 postinfection. This higher organism burden most likely impacted disease pathogenesis; however, the development of Th2 cell-mediated adaptive immune response most likely contributed to lesion severity at later time points during infection. Our studies demonstrate that the upper and lower respiratory tracts are separate and distinct in their cytokine requirements for generating immunity against mycoplasma infection.

Cytokine and Chemokine Transcription Profile during Mycoplasma pulmonis Infection in Susceptible and Resistant Strains of Mice: Macrophage Inflammatory Protein 1β (CCL4) and Monocyte Chemoattractant Protein 2 (CCL8) and Accumulation of CCR5+ Th Cells

ABSTRACT The progression of murine mycoplasma pneumonia is dependent on T cells and other immune cells. The role of cytokines in immunity are complex, and identifying the network of cytokines produced after infection of mice is essential in dissecting the key cytokine cascades involved mycoplasma disease pathogenesis. In the present study, mRNA expression of 143 different cytokines, chemokines, or receptors were evaluated in lung tissues from both susceptible (BALB/c and C3H/HeN) and resistant (C57BL/6) mice after Mycoplasma pulmonis infection. To accomplish this, membrane-based cDNA microarrays were used to monitor changes mRNA expression in lungs. There was a clear association with disease susceptibility and development of cytokine mRNA expression. In addition to proinflammatory cytokines, mRNA expression of an anti-inflammatory cytokine, interleukin-10, increased with disease severity, suggesting an attempt to moderate the severity of the inflammatory response. Furthermore, it is clear that an array of chemokines produced in susceptible mice could contribute to the recruitment and maintenance of inflammatory cells at the site of disease. In support of this, there was an increase in macrophage inflammatory protein 1β (MIP-1β; CCL4) and monocyte chemoattractant protein 2 (MCP-2; CCL8) mRNA levels from mycoplasma-infected mice and a corresponding accumulation of CD4+ Th cells expressing the MIP-1β/MCP-2 receptor, CCR5, in the lungs of mice. Furthermore, MIP-1β- and MCP-2-producing cells and CD4+ T cells were found to be in close association in pulmonary lesions. Thus, there was a significant cytokine response associated with disease pathogenesis, and these studies provide important leads and insights into ongoing cytokine- and chemokine-mediated processes in this persistent inflammatory disease.

Hyperbaric oxygen treatment attenuates the pro-inflammatory and immune responses in apolipoprotein E knockout mice

Chronic hyperbaric oxygen (HBO) therapy significantly attenuates atherosclerosis in New Zealand white rabbits as well as the apoE knockout (KO) mice, independent of plasma lipid concentrations and lipoprotein profiles. Because atherosclerosis has many features of a chronic inflammatory disease, in which both cell-mediated and humoral immune responses participate, we examined the effect of HBO treatment on various aspects of the immune response. We now demonstrate that in apoE KO mice, HBO treatment significantly reduces the circulating levels of antibodies to (MDA)LDL, both in the IgG and IgM class, as well as the delayed-type hypersensitivity (DTH) response to oxLDL challenge. Furthermore, HBO treatment results in a profound attenuation in the production of pro-inflammatory cytokines in response to an inflammatory stimulus (LPS), which is accompanied by a marked increase in the constitutive production of the anti-inflammatory cytokine IL-10 by spleen cells, independent of antigen specificity, as indicated by polyclonal activation of T cells. Our results demonstrate that HBO treatment results in the dampening of T and B cell-mediated responses to oxLDL or inflammatory stimuli.

Stress-induced differences in primary and secondary resistance against bacterial sepsis corresponds with diverse corticotropin releasing hormone receptor expression by pulmonary CD11c+ MHC II+ and CD11c-MHC II+ APCs

Stress responses have been associated with altered immunity and depending upon the type of stressor, can have diverse effects on disease outcomes. As the first line of defense against potential pathogens, alterations in cellular immune responses along the respiratory tract can have a significant impact on the manifestation of local and systemic disease. Utilizing a murine model of respiratory pneumonia, the current study investigated the effects of restraint stress on the induction of primary and secondary immunity along the respiratory tract, influencing host susceptibility. Female CD-1 mice were subjected to three hours of restraint stress over a period of four days followed by primary and secondary Streptococcus pneumoniae infection via intranasal route. Stress exposure led to increased retention of bacterial carriage in the lungs, enhanced polymorphonuclear cells and a preferential decrease in pulmonary CD11c(+) MHC II(+) cells resulting in delayed lethality during primary infection but significant impairment of acquired immune protection after secondary infection. We also provide evidence to support a role for lung-associated corticotropin releasing hormone regulation through peripheral CRH and diverse CRH receptor expression by MHC II(+) antigen presenting cells (APCs). We conclude that repeated restraint stress has distinct influences on immune cell populations that appear to be important in the generation of innate and adaptive immune responses along the respiratory tract with the potential to influence local and systemic protection against disease pathogenesis.