Lawrence Transfer Factor: Transference of Specific Immune Memory by Dialyzable Leukocyte Extract from a CD8+ T Cell Line

Lawrence transfer factor (TF) is defined as dialyzable leukocyte extract (DLE) that can transfer antigen-specific cell-mediated immunity from a person testing positive for the antigen in a delayed type hypersensitivity skin test manner to a person negative for the same antigen. A recent article by Myles et al1 has identified a DLE isolated from an established CD8+ T cell line capable of transferring antigen-specific immunity. The DLE contains a portion of the beta chain of the T cell receptor and additional nucleotide and protein factors that are being subjected to further modern biochemical analysis. After months of study that included interviews of TF physician-scientists, we conclude that an antigen-specific TF exists for most, if not all, antigens. By working from a CD8+ T cell line with modern biochemical technology, it should be possible to identify and patent products capable of treating infectious diseases, antigen-responsive cancers, and autoimmune disorders.

Leprosy as a model to understand cancer immunosurveillance and T cell anergy

Leprosy is a disease caused by Mycobacterium leprae that presents on a spectrum of both clinical manifestations and T cell response. On one end of this spectrum, tuberculoid leprosy is a well-controlled disease, characterized by a cell-mediated immunity and immunosurveillance. On the opposite end of the spectrum, lepromatous leprosy is characterized by M. leprae proliferation and T cell anergy. Similar to progressive tumor cells, M. leprae escapes immunosurveillance in more severe forms of leprosy. The mechanisms by which M. leprae is able to evade the host immune response involve many, including the alterations of lipid droplets, microRNA, and Schwann cells, and involve the regulation of immune regulators, such as the negative checkpoint regulators CTLA-4, programmed death 1, and V-domain Ig suppressor of T cell activation-important targets in today's cancer immunotherapies. The means by which tumor cells become able to escape immunosurveillance through negative checkpoint regulators are evidenced by the successes of treatments, such as nivolumab and ipilimumab. Many parallels can be drawn between the immune responses seen in leprosy and cancer. Therefore, the understanding of how M. leprae encourages immune escape during proliferative disease states has potential to add to our understanding of cancer immunotherapy.

Diphencyprone Treatment of Alopecia Areata: Postulated Mechanism of Action and Prospects for Therapeutic Synergy with RNA Interference

Diphencyprone (DPCP) is a potent topical sensitizing agent that has been used since the late 1970s by physicians for the treatment of alopecia areata (AA), viral warts (human papillomavirus) and cutaneous metastases of melanoma. Although to date the compound is not approved as a drug by the FDA or EMA, physicians have continued to use DPCP because of its proven effects in these dermatological conditions. The use of the drug has been highly variable because of differences in compounding, and as a result, the literature reports vary widely in the concentrations used for sensitization and challenge treatment with DPCP. The efficacy of DPCP has generally been ascribed to immunological reactions by the host. Inducing inflammation with a contact sensitizer is counterintuitive to treating AA, an autoimmune disorder. We have hypothesized that the body's attempt to downregulate the inflammation caused by the contact sensitizer may also ameliorate AA. Studies using microarray and miRNA profiling may provide information about how DPCP induces inflammation in human skin at different times. Gene targets and microRNAs identified through these data may be modulated by an RNA interference approach to enhance DPCP efficacy and response rates. In addition, this approach may result in the discovery and development of drugs that are more potent and selective for the treatment of AA.

A potential role for miRNAs in topical drug development

MicroRNAs (miRNAs) are small, noncoding regulatory RNAs demonstrated to play a role in regulating diverse physiologic and pathologic processes in humans. The understanding of their role in dermatologic disorders has been rapidly expanding, and technological advances in the field of small RNA therapeutics have provided a window into the possibilities for using our understanding of miRNA activities as a stepping-stone to treating a variety of skin diseases. The topical immunomodulator diphenylcyclopropenone (DPCP) has been used for the treatment of skin cancers and alopecia areata and represents one of many drug targets with potential for manipulation of miRNA pathways to enhance clinical efficacy. By exploring the miRNA pathways involved in specific skin diseases and the miRNAs impacted by drug treatments, investigators will discover new ways to treat skin disease and improve preexisting therapies.

Pseudoepitheliomatous hyperplasia and transepidermal elimination in lepromatous leprosy: does T-cell plasticity play a role?

BACKGROUND

The longstanding concept of a Th1-Th2 dichotomy in leprosy, with Th1-predominant tuberculoid leprosy and Th2-predominant lepromatous leprosy (LL), has recently been challenged, and Cbl-b overexpression may emerge as an important factor in anergy and progression of LL. Moreover, Th17 and Th22 subsets have been identified as Th1-Th2 modulators in inflammatory skin diseases, most notably psoriasis, but their roles in leprosy have not yet been elucidated. The occurrence of pseudoepitheliomatous hyperplasia (PEH) with transepidermal elimination of mycobacteria in LL patients, which could theoretically be a portal for contact transmission, thus raises important immunological questions: Do Th17 and/or Th22 subsets mediate epidermal proliferation akin to Th1-driven psoriasis in supposedly Th2-predominant LL disease, and is the Th1-Th2 immunostat set systemically or locally? Furthermore, which microRNAs (miRs), signal transducers, and activators of transcription (STAT) proteins regulate this transition in leprosy, if any, and does differential Cb1-b expression play a role?

OBSERVATION

A 71-year-old man presented with an infiltrative dermopathy characteristic of LL, as well as several hyperkeratotic plaques. Microscopic examination of the hyperkeratotic lesions demonstrated PEH with loss of the grenz zone and transepidermal elimination of acid-fast bacilli, whereas classic histopathologic features of LL were present at other sites.

HYPOTHESES

We hypothesize that: Th17 and Th22 T-cell subsets act locally to induce T-cell plasticity in LL lesions, manifesting PEH; miR-181a is normal or increased in LL lesions with PEH compared to its expressional loss in classic LL lesions; miR-21 and STAT3 are increased in LL lesions with PEH, given their association with epithelial hyperproliferation; and Cbl-b is diminished in LL lesions with PEH compared to classic LL lesions.

CONCLUSION

By understanding the factors that regulate T-cell and cytokine responses in leprosy, it should be possible to recognize these dynamic immunologic processes clinically and histopathologically and devise specific immunologic interventions.

Ingenol mebutate: potential for further development of cancer immunotherapy

Ingenol mebutate is a diterpene ester derived from the plant Euphorbia peplus and is FDA approved for the topical treatment of actinic keratoses (AK). Shown to be efficacious with as little as a 3-day trial, this compound is being further tested for the topical treatment of other nonmelanoma skin cancers with promising preclinical data. In an effort to elucidate the molecular mechanism of this novel drug, Stahlhut et al. (2012) suggest a role for calcium and apoptosis. Further studies are needed to evaluate the intracellular mechanisms of ingenol mebutate-mediated cytotoxicity. Additionally, studies such as this not only shed light on the mechanism of ingenol mebutate and its derivatives, but also pave the way for evaluating the involvement of the immune system in eliminating drug-treated cells and tissues. This has important implications for the development of novel topical immune modulatory products and the field of topical immunotherapy.

The study of simple chemicals in animals and man: mechanisms of contact sensitivity

When simple chemical are applied to the skin, a series of events ensues that under some conditions ultimately results in contact sensitivity (CS), a proven cell-mediated immune response (CMI). Since the discovery of CMI using picryl-Cl (PCl) in 1942, we have learned a great deal on the cellular mechanisms involved in CS, including the potential to treat warts, skin cancer, autoimmune disorders, and allergies. In this review we summarize some of the basic mechanisms of both the innate and acquired immune systems involved in CS.

Lessons of leprosy: the emergence of TH17 cytokines during type II reactions (ENL) is teaching us about T-cell plasticity

BACKGROUND

Leprosy was the first disease classified according to the thymus derived T-cell in the 1960s and the first disease classified by the cytokine profile as intact interferon-γ (IFN-γ) and interleukin-2 (IL2) or TH1 (tuberculoid) and deficient IFN-γ and IL2 or TH2 (lepromatous), in the 1980s.

OBJECTIVE

In the present study, we set out to explore the T helper 17 (TH17) lymphocyte subset, the hallmark of T-cell plasticity, in skin biopsies from patients with erythema nodosum leprosum (ENL) who were treated with thalidomide.

METHOD

RNA was extracted from paraffin embedded tissue before and after thalidomide treatment of ENL and RT-PCR was performed.

RESULTS

IL17A, the hallmark of TH17, was consistently seen before and after thalidomide treatment, confirming the TH17 subset to be involved in ENL and potentially up-regulated by thalidomide.

CONCLUSION

A reduction in CD70, GARP, IDO, IL17B (IL-20), and IL17E (IL-25), coupled with increases in RORγT, ARNT, FoxP3, and IL17C (IL-21) following thalidomide treatment, opens the door to understanding the complexity of the immunomodulatory drug thalidomide, which can operate as an anti-inflammatory while simultaneously stimulating cell-mediated immunity (CMI). We conclude that TH17 is involved in the immunopathogenesis of ENL and that thalidomide suppresses inflammatory components of TH17, while enhancing other components of TH17 that are potentially involved in CMI.

CD70 and Th17 are involved in human contact sensitivity

CD70 (CD27L) has been shown to be preferentially expressed on Th1, but not Th2, CD4+ lymphocytes in murine contact sensitivity. The CD70-CD27 co-stimulatory pathway as well as the Th17 subset of lymphocytes have also been identified in human contact sensitivity reactions. The authors have previously reported increased expression of CD70 and the Th17-specific transcription factor retinoid orphan receptor gamma T in the elicitation phase of allergic contact dermatitis by reverse transcriptase-polymerase chain reaction. The manipulation of these pathways has potential for ameliorating autoimmune and inflammatory disorders such as allergic contact dermatitis, psoriasis and rheumatoid arthritis. Also, upregulation of the CD70-CD27 and Th17 pathways has been associated with the remarkable ability of topical sensitizers to treat warts and skin cancers including melanoma. As natural killer and natural killer T cells are also involved in contact sensitivity, future studies investigating the function of these cells are necessary to elucidate the transition between innate and acquired immune responses in the context of the Th1/Th2/Th17 and regulatory T cell paradigm.

TH17 is involved in the remarkable regression of metastatic malignant melanoma to topical diphencyprone

The authors provide an update on a previously reported patient with in-transit metastatic melanoma of the scalp treated with topical diphencyprone (DPCP). Molecular studies implicate the thymus-derived TH17 lymphocyte subset in a remarkable immunotherapeutic regression. The authors performed RT-PCR of total RNA from paraffin-embedded tissue before and after treatment with DPCP. Before treatment with DPCP, the authors found elevated expression of IL 17C/D/E/F; after treatment there was no detectable expression. Conversely, increased expression of PLZF/CD27 and CTLA4 was seen after treatment with no expression before treatment. No expression of IL17A/B, CD7, RORgTand FoxP3 were before or after treatment. Conclusions are limited to only the time samples were obtained. Remarkable regression of an in-transit metastatic melanoma treated with the immunomodulatory agent DPCP showed gain and loss of gene expression of the TH17 pathway. Further study of this pathway from NK to NK-T to TH7 and TH1 cells both with and without accessory or dendritic cells will improve understanding of contact sensitizers as topical immunomodulators.

The role of complement in dendritic cell (DC) control of T-cell subsets

This section of the Journal of Drugs in Dermatology (JDD) is dedicated to Dendreon's Provenge (Sipuleucel-T), the first therapeutic DC vaccine proven effective and approved by the United States (U.S.) Food and Drug Administration (FDA) for advanced cancer. This editorial will discuss three articles in this issue, their relationship to Provenge and the recent TH17-Treg subsets that are regulated by CD46.

Thalidomide and analogues: potential for immunomodulation of inflammatory and neoplastic dermatologic disorders

Thalidomide and analogues are a class of immunomodulatory drugs or IMiDS. Thalidomide was initially approved by the U.S. Food and Drug Administation for treatment of erythema nodosum in leprosy and is now approved for multiple myeloma as well. A second generation IMiD, lenalidomide, is also approved for multiple myeloma and refractory myelodysplastic syndrome. Discovery of this class of drugs has been serendipitous and empirical, as the drug targets have been unknown. In this review, the authors integrate recent identification of drug targets of IMiDS, which include the inducible form of nitric oxide synthase (iNOS), Rho GTPase and caspase-1, with the developments in the understanding of the molecular biology of human inflammatory, infectious and neoplastic skin disorders. Because thalidomide reemerged through leprosy, the original disease classified by the T cell, the authors have also emphasized advances in the understanding of T-cell subsets in human skin disorders.

Effect of thalidomide on nitric oxide production in lipopolysaccharide-activated RAW 264.7 cells

Thalidomide is anti-inflammatory under some conditions, yet has been reported to up-regulate Th1 (T helper 1) immunity measured by increased IL-2 (Interleukin-2) and gamma interferon. The authors have assessed the effect of thalidomide and analogues, di- and tri-thiothalidomide, on a lipopolysaccharide (LPS) activated macrophage cell line (RAW 246.7 cells). The authors' findings showed that nitric oxide (NO) was significantly inhibited by thalidomide (15%) and its analogues (di-thiothalidomide; 15%, tri-thiothalidomide; 32%). The proinflammatory molecules TNF-alpha (tumor necrosis factor-alpha) and IL-6 were not significantly inhibited. Pretreatment with thalidomide and analogues before activation was not different from simultaneous treatment. Inhibition of inducible nitric oxide synthase (iNOS) may prove to be an important target for the anti-inflammatory and anti-cancer effects of thalidomide and related immunomodulatory drugs (IMiDs).

Lepromatous leprosy

Lepromatous leprosy is a form of chronic granulomatous disease that is caused by infection with Mycobacterium leprae. Early involvement is marked by widespread, ill-defined, erythematous papules and plaques. With early intervention, leprosy is a curable disease; however, if not recognized and treated promptly, permanent sequelae and disability result. We present a patient with long-standing lepromatous leprosy who exhibits many of these sequelae.

Expression of CD70 and the TH17 transcription factor RORgammaT in human contact dermatitis

Contact sensitizers are a major cause of inflammatory skin disease and as topical immunomodulators also have the potential for treating cancer, viral diseases and certain autoimmune disorders. In the present study, the authors identify the upregulation of the TH17 lymphocyte subset transcription factor retinoid orphan receptor gamma T (RORgammaT) and the CD70 costimulatory pathway in human contact sensitivity (CS) using molecular techniques. Identification of this important new subset of T lymphocytes and a recognized costimulatory pathway offers potential for ameliorating CS and insight into antitumor and antiviral mechanism of haptens as topical immunomodulators.

The role of the armadillo and sooty mangabey monkey in human leprosy

BACKGROUND

The armadillo was the first animal model of leprosy. Its role in the transmission of leprosy remains controversial. The sooty mangabey model of leprosy led to the discovery that rhesus monkeys were more susceptible to leprosy when coinfected with simian immunodeficiency virus (SIV), but that leprosy may play a protective role against acquired immunodeficiency syndrome (AIDS) mortality. Recently, molecular methods have been developed for leprosy and may help resolve the role of zoonoses in leprosy.

OBSERVATIONS

The recent identification of a case of leprosy in a native-born American on the east coast of the USA and the identification of leprosy as an immunologic reconstitution inflammatory syndrome (IRIS) in human immunodeficiency virus (HIV)-positive cases raise the question of what role zoonoses may play in leprosy.

CONCLUSIONS

Leprosy in armadillos and sooty mangabeys has been manipulated by human experimentation. In the case of the armadillo, further study, including molecular techniques, is required to elucidate the role of the armadillo as a zoonosis in human leprosy. Experimentation with the sooty mangabey led to the discovery of an interaction between SIV and leprosy in rhesus monkeys, and prompted the continued investigation of the relationship between HIV and leprosy.

Erythrokeratoderma variabilis

A 51-year-old woman presented with well-demarcated, erythematous patches and hyperkeratotic plaques that were arranged symmetrically on the upper extremities. Her skin lesions first appeared at age 17, and there was a family history of similar skin lesions in nine of her eleven siblings. Physical and emotional stress increased the number and intensity of her skin lesions as did chocolate. The distribution of lesions on her skin had changed over time; however, the lesions consistently appeared symmetrically and favored the extensor surfaces of her extremities. The physical examination, histopathologic findings, and family history were consistent with a diagnosis of erythrokeratoderma variabilis (EKV), a rare genodermatosis caused by various mutations in connexin genes. Connexin genes code for proteins that form intercellular channels called gap junctions that allow for transport and signaling between neighboring cells in the epidermis. Mutations in connexin-31 and connexin-30.3 are known to cause the EKV phenotype, which presents as erythematous patches and hyperkeratotic plaques. Studies to examine the effectiveness of treatment of EKV have not been performed; however, several case reports suggest the efficacy of oral retinoids. After 4 months of acitretin 25 mg per day, our patient experienced near complete clearance of her skin lesions.

Molecular origin of endemic leprosy in New York City

We report an indigenous case of leprosy in New York City in an immunocompetent patient who was infected with a Mycobacterium leprae genotype that is consistent with an exogenous origin. Physicians in the eastern United States should be alerted that, although most patients who develop leprosy in the United States are foreign born, native-born Americans are also susceptible to the infection.

Heat-shock proteins as drugs: potential applications in cancer, infections, and autoimmune and atopic diseases

Heat-shock proteins (HSPs) serve as both a valuable target as well as a potent tool in the therapy of melanoma and human papillomavirus infections. HSPs have been found to associate with key pathogenic antigens and, under different circumstances, activate or suppress both innate and adaptive immunity via several mechanisms. The dominant mechanism of HSP is as a chaperonin to upregulate antigens on antigen-presenting cell surfaces. While no HSP-based therapies are currently FDA approved, several are currently in phase III clinical trials. This study reviews the current literature on therapeutic studies of HSP and the significant role these proteins are likely to play in future therapeutic approaches to neoplasms, infections, and inflammatory diseases of the skin.

CpG oligodeoxynucleotide-enhanced humoral immune response and production of antibodies to prion protein PrPSc in mice immunized with 139A scrapie-associated fibrils

Prion diseases are characterized by conversion of the cellular prion protein (PrP(C)) to a protease-resistant conformer, the srapie form of PrP (PrP(Sc)). Humoral immune responses to nondenatured forms of PrP(Sc) have never been fully characterized. We investigated whether production of antibodies to PrP(Sc) could occur in PrP null (Prnp(-/-)) mice and further, whether innate immune stimulation with the TLR9 agonist CpG oligodeoxynucleotide (ODN) 1826 could enhance this process. Whether such stimulation could raise anti-PrP(Sc) antibody levels in wild-type (Prnp(+/+)) mice was also investigated. Prnp(-/-) and Prnp(+/+) mice were immunized with nondenatured 139A scrapie-associated fibrils (SAF), with or without ODN 1826, and were tested for titers of PrP-specific antibodies. In Prnp(-/-) mice, inclusion of ODN 1826 in the immunization regime increased anti-PrP titers more than 13-fold after two immunizations and induced, among others, antibodies to an N-terminal epitope, which were only present in the immune repertoire of mice receiving ODN 1826. mAb 6D11, derived from such a mouse, reacts with the N-terminal epitope QWNK in native and denatured forms of PrP(Sc) and recombinant PrP and exhibits a K(d) in the 10(-)(11) M range. In Prnp(+/+) mice, ODN 1826 increased anti-PrP levels as much as 84% after a single immunization. Thus, ODN 1826 potentiates adaptive immune responses to PrP(Sc) in 139A SAF-immunized mice. These results represent the first characterization of humoral immune responses to nondenatured, infectious PrP(Sc) and suggest methods for optimizing the generation of mAbs to PrP(Sc), many of which could be used for diagnosis and treatment of prion diseases.

Identification of novel hsp65 RFLPs for Mycobacterium leprae

Leprosy or Hansen's disease is a chronic infectious disease caused by an acid-fast bacillus, Mycobacterium leprae (M. leprae). The bacilli proliferate in macrophages infiltrating the skin and gain entry to the dermal nerves via the laminar surface of Schwann cells where they replicate. After entry, the Schwann cells proliferate and then die. Conclusive identification of M. leprae DNA in a sample can be obtained by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for the heat shock 65 gene (hsp65). Molecular epidemiology will make it possible to study the global distributions of M. leprae, explore the relationship between genotypes-incidence rates, mode of transmission, and the type of disease (tuberculoid vs. lepromatous). We amplified DNA using PCR for the hsp65 gene from 24 skin lesions from patients diagnosed with various types of leprosy. Fifteen out of 24 were positive for the hsp65 gene. Digestion with HaeIII-PAGE for the RFLP confirmation of the presence of M. leprae DNA showed the typical pattern in 5 out of 24 and 2 novel patterns in 10 out of 24 patients. We confirmed the presence of M. leprae DNA by sequencing the genes for gyraseA or B and folP, which contained only M. leprae specific single nucleotide polymorphisms (SNPs). Thus, we describe novel hsp65 RFLPs for M. leprae found in a high frequency making them ideal for future epidemiology and transmission studies.

Topical diphenylcyclopropenone as a measure of immune competence in HIV-seropositive subjects

BACKGROUND

CD4 T cell counts are recognized as the standard method for monitoring HIV-seropositive patients and, along with viral load, are clinically important as indicators for initiating highly active antiretrovival therapy (HAART). Skin reaction scores following topical application of diphenylcyclopropenone (DPC) also demonstrate diagnostic utility as a functional measure of immune competence.

METHODS

We used low sensitizing doses of DPC in 40 patients applied in a non-volatile, non-irritating topical delivery system to assess immune competence in 40 HIV-seropositive subjects with a range of CD4 T cell counts. Standardized patch test reading scores were used, with 2+ or greater scores (erythema and induration) indicative of a positive response. The patch test scores were then compared with CD4 counts.

RESULTS

Application of DPC in concentrations of 0.4% and 0.2% successfully resulted in 90% sensitivity skin reaction scores in subjects with >300 CD4 T cells/microL, following a single 0.1 mL application to the inner aspect of the arm. Lower DPC concentrations of 0.1% and 0.05% were too low for initial sensitization reactions. Three subjects with CD4 counts between 150 and 300 cells/microL showed positive skin reactions indicating that this DPC test gives the clinician information on cellular immunity beyond the CD4 count.

CONCLUSION

We conclude that a single topical application of DPC at concentrations between 0.2% and 0.4% can serve as a measure of immune competence in HIV-seropositive patients. As a functional measure of immunocompetence, this DPC test provides information beyond a CD4 count, which is particularly relevant to HIV-positive subjects with CD4 counts between 200 and 350 cells/microL.

Haptens as drugs: contact allergens are powerful topical immunomodulators

For the past 40 years, dermatologists have safely used contact sensitizers such as dinitrochlorobenzene (DNCB), diphenylcyclopropenone (DPCP), and squaric acid dibutylester (SADBE) for the treatment of warts, alopecia areata, and even skin cancers. Most of these studies have utilized these powerful topical immunomodulators in acetone, a volatile solvent that precludes development of contact sensitizers as products. We have overcome these problems and stabilized these topical immunomodulators in a non-volatile, nonirritating GRAS (generally regarded as safe) vehicle. The current review article covers the traditional use of contact sensitizers for a variety of benign and malignant conditions and discusses possible mechanisms in relation to developments in modem molecular immunodermatology.

Platycodin D and D3 isolated from the root of Platycodon grandiflorum modulate the production of nitric oxide and secretion of TNF-α in activated RAW 264.7 cells

Platycodon D (PD) and D3 (PD3) isolated from Platycodon grandiflorum has been previously reported to show anti-inflammatory activities in rats. In this study, the production of proinflammatory cytokines, nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) was examined in a macrophage like cell line, RAW 264.7 cells, in the presence of PD and PD3, oligosaccharide derivatives of oleanolic acid. RAW 264.7 cells activated with lipopolysaccharide (LPS; 1 microg/ml) and recombinant interferon-gamma (rIFN-gamma; 50 U/ml) were treated with various doses of PD and PD3 for 24 h. Supernatants were analyzed for the production of NO and TNF-alpha using Griess reagent and enzyme-linked immunosorbent assay (ELISA), respectively. NO was inhibited in a dose-dependent manner by PD and PD3 (IC50 of platycodin D approximately 15 uM, IC50 PD3 approximately 55 uM). The expression of inducible NOS (iNOS) was inhibited by these compounds, as measured by Western blot analysis, as well as the expression of iNOS mRNA, as measured by Northern blot analysis. RAW 264.7 cells were treated at various times after LPS and activation with PD. Treatment with PD up to 8 h after activation showed significant inhibition of NO, indicating that early signal transduction of NOS synthesis may be inhibited by PD. In contrast to NO, secretion of TNF-alpha as well as expression of TNF-alpha mRNA was increased by PD and PD3. TNF-alpha secretion from RAW 264.7 cells was measured at various times after LPS and rIFN-gamma activation. Secretion of TNF-alpha was also increased up to 8 h postactivation, suggesting that PD may stimulate TNF-alpha synthesis or inhibit degradation of TNF-alpha mRNA. Oleanolic acid was without effect on both the production of NO and secretion of TNF-alpha. These data suggest a dichotomous regulation of these important proinflammatory mediators by PD and PD3.

Reversal reaction to Hansen's disease

A 25-year-old man with a history of mid-borderline (BB) Hansen's disease developing a reversal reaction after starting dapsone and rifampin therapy is presented. His clinical features included erythematous, edematous plaques and peripheral neuropathy. Reversal reactions are caused immunologically by enhanced cell-mediated (Th-1) immunity to Mycobacterium leprae, resulting in inflammation of infected tissues, such as skin and nerves. Acute neuritis can lead to permanent nerve damage and necessitate prompt treatment with prednisone and/or clofazamine.

Pentoxifylline downregulates nitric oxide and tumor necrosis factor-alpha induced by mycobacterial lipoarabinomannan in a macrophage cell line

Pentoxifylline (PTX), a phosphodiesterase inhibitor, is known to downregulate tumor necrosis factor-alpha (TNF-alpha) secretion induced by lipopolysacchride (LPS) and gamma interferon (IFN-gamma). We have had limited success in treating leprosy reactions, including erythema nodosum leprosum (ENL), in which TNF-alpha has been identified as a major proinflammatory cytokine. PTX inhibited production of NO (IC50 approximately equal to 1.0 mg/ml) and TNF-alpha (IC50 approximately equal to 0.05 mg/ml) in a dose-dependent fashion. As little as 0.5 mg/ml of PTX decreased NO production and 0.01 mg/ml of PTX inhibited TNF-alpha production. Western blot analyses demonstrated that iNOS was suppressed by PTX. Northern blot analyses showed significant reduction of TNF-alpha mRNA. We conclude that PTX is an effective inhibitor of lipoarabinomannan (LAM)-induced TNF-alpha production at both the product and transcriptional levels in our macrophage cell line. PTX also showed moderate inhibition of NO at the product level as well as translation of iNOS.

Regulation of nitric oxide induced by mycobacterial lipoarabinomannan in murine macrophages: effects of interferon-beta and taurine-chloramine

We examined the effects of interferon beta (IFN-beta) on the production of liporabinomannan (LAM)-induced nitric oxide (NO) in peritoneal macrophages from low-responder and high-responder (C3H/HeJ and C3H/OuJ) mice. NO was produced in a dose response when induced by lipo-polysaccharide (LPS) or LAM plus interferon gamma (IFN-gamma) or IFN-beta in both high- and low-responder mice. In contrast to IFN-gamma, both high- and low-responder mice failed to induce nitrite production when IFN-beta was added, except at a high concentration of IFN-beta. Tau-Cl (0.5 mM) inhibited NO production about 50% in the high-responder strain when cells were activated with LPS or LAM in combination with either IFN-beta or IFN-gamma, and almost abolished NO production at 1.0 mM. In the low-responder strain, Tau-Cl (0.5 mM) significantly inhibited NO production when cells were activated with IFN-gamma or IFN-beta in addition to LPS or LAM, but did not completely inhibit NO production at 1.0 mM. Tau-Cl appears to play a potent role in regulating inflammatory reaction-induced bacterial or mycobacterial organisms. These data indicate a pivotal role for IFN-gamma and IFN-beta for the production of LPS and LAM initiated NO in peritoneal macrophages from low-responder (C3H/HeJ) mice.

Specific and nonspecific immunoregulatory events in the clonal response of human lymphocytes in vitro

Stimulation of sensitive leucocyte populations with near optimal concentrations of soluble microbial antigens results in vigorous lymphocyte proliferation when 3H-thymidine incorporation is measured after 4-8 days. Lymphoblasts in these cultures revert to small lymphocytes after 10-14 days, at which time they are often refractory to any stimulant including the original incubating antigen. When these primed lymphocytes are irradiated with 500-1000 R to block their proliferation and added to fresh leucocyte culture from the same individual (autologous), they usually, but not invariably, reduce the proliferation of the unirradiated fresh leucocyte cultures. Exposure to 6000 R reduced the suppressor activity. Reduction was specific for the microbial antigen with which they were originally generated, but, more often, a combination of both specific and nonspecific suppression was observed. These data provide good evidence, with reciprocal specificity, for the generation of antigen specific suppression in vitro.

Mycobacterial lipoarabinomannan induces nitric oxide and tumor necrosis factor alpha production in a macrophage cell line: down regulation by taurine chloramine

Avirulent mycobacterium H37Ra lipoarabinomannan (LAM) elicited nitric oxide (NO) and tumor necrosis factor alpha in a dose-dependent manner in a murine macrophage cell line, RAW 264.7 cells. H37Ra LAM and recombinant gamma interferon were highly synergistic for NO production. The production of NO and the release of tumor necrosis factor alpha stimulated by H37Ra LAM plus recombinant gamma interferon in RAW 264.7 cells are inhibited by taurine chloramine.