Correlates of GLA family adjuvants' activities.

Lipopolysaccharide (LPS) is a well-defined agonist of Toll-like receptor (TLR) 4 that activates innate immune responses and influences the development of the adaptive response during infection with Gram-negative bacteria. Many years ago, Dr. Edgar Ribi separated the adjuvant activity of LPS from its toxic effects, an effort that led to the development of monophosphoryl lipid A (MPL). MPL, derived from Salmonella minnesota R595, has progressed through clinical development and is now used in various product-enabling formulations to support the generation of antigen-specific responses in several commercial and preclinical vaccines. We have generated several synthetic lipid A molecules, foremost glucopyranosyl lipid adjuvant (GLA) and second-generation lipid adjuvant (SLA), and have advanced these to clinical trial for various indications. In this review we summarize the potential and current positioning of TLR4-based adjuvant formulations in approved and emerging vaccines.

The molecular genetics of inflammatory, autoimmune, and infectious diseases of the sinonasal tract: a review.

CONTEXT: The sinonasal tract is frequently affected by a variety of nonneoplastic inflammatory disease processes that are often multifactorial in their etiology but commonly have a molecular genetic component. OBJECTIVE: To review the molecular genetics of a variety of nonneoplastic inflammatory diseases of the sinonasal tract. DATA SOURCES: Inflammatory lesions of the sinonasal tract can be divided into 3 main categories: (1) chronic rhinosinusitis, (2) infectious diseases, and (3) autoimmune diseases/vasculitides. The molecular diagnosis and pathways of a variety of these inflammatory lesions are currently being elucidated and will shed light on disease pathogenesis and treatment. CONCLUSIONS: The sinonasal tract is frequently affected by inflammatory lesions that arise through complex interactions of environmental, infectious, and genetic factors. Because these lesions are all inflammatory in nature, the molecular pathology surrounding them is most commonly due to upregulation and down-regulation of genes that affect inflammatory responses and immune regulation.

Immune reconstitution inflammatory syndrome and tropical dermatoses.

The human immunodeficiency virus (HIV) pandemic has disproportionately affected tropical regions of the world, where dermatoses, such as leprosy and leishmaniasis, rarely encountered in temperate climates, are endemic. Although the introduction of highly active antiretroviral therapy (HAART) has been lifesaving, a few patients undergoing HAART experience clinical deterioration caused by immune reconstitution inflammatory syndrome (IRIS). This article explores the range of tropical dermatoses that are reported to date with associated IRIS events.

Anti-desmoglein-1 antibodies in onchocerciasis, leishmaniasis and Chagas disease suggest a possible etiological link to Fogo selvagem.

Pemphigus foliaceus (PF) and the endemic form Fogo Selvagem (FS) are mediated by pathogenic antibodies to the EC1-2 domains of desmoglein-1. There is a preclinical phase with antibodies to only EC5. Based on geographic clustering of cases, FS is thought to have an, as yet unidentified, environmental trigger. In this study we have searched for anti-desmoglein-1 antibodies in sera from parasitic (leishmaniasis, Chagas, and onchocerciasis), and infectious diseases (leprosy and South American (SA) blastomycosis), which are prevalent in the same geographic regions of Brazil as FS. A specific and sensitive desmoglein-1 ELISA detected antibodies in 34 of 41 onchocerciasis (83%), 38 of 88 leishmaniasis (43%), 18 of 31 Chagas disease (58%), 7 of 28 SA blastomycosis (25%), and 14 of 83 leprosy sera (17%). These sera recognized epitopes restricted to the EC5 domain. These findings identify several etiological factors for FS. It is hypothesized that a component of insect vector saliva, rather than the parasite itself may trigger an antibody response to EC-5. In persons with the known HLA susceptibility alleles and living in endemic areas, a response to the EC1-2 domains may subsequently develop by epitope spreading with associated clinical signs of FS.

Macrophage NRAMP1 and its role in resistance to microbial infections.

The identification and characterization of genetic factors influencing natural susceptibility to infectious diseases in humans and in model organisms, such as the laboratory mouse, can provide new insight into the basic mechanisms of host defense against infections. In the mouse, resistance or susceptibility to infection with intracellular pathogens such as Salmonella, Mycobacterium and Leishmnania is controlled by the Natural resistance associated macrophage protein (Nramp1) gene on chromosome 1, which influences the rate of intracellular replication of these parasites in macrophages. Nramp1 codes for an integral membrane protein, which is expressed exclusively in macrophage/monocytes and polymorphonuclear leukocytes. The protein is localized to the endosomal/lysosomal compartment of the macrophage and is rapidly recruited to the membrane of the particle-containing phagosome upon phagocytosis. Nramp defines a novel family of functionally related membrane proteins including Nramp2, which was recently shown to be the major transferrin-independent uptake system of the intestine in mammals. This observation supports the hypothesis that the phagocyte-specific Nramp1 protein may regulate the intraphagosomal replication of antigenically unrelated bacteria by controlling divalent cation concentrations at that site. Recent genetic studies have found that allelic variants at the human NRAMP1 locus are associated with susceptibility to leprosy (Mycobacterium leprae) and tuberculosis (Mycobacterium tuberculosis) and possibly with the onset of rheumatoid arthritis.

Genetics of host resistance and susceptibility to intramacrophage pathogens: a study of multicase families of tuberculosis, leprosy and leishmaniasis in north-eastern Brazil.

Genetic analysis of disease phenotypes segregating in recombinant inbred, congenic and recombinant haplotype mouse strains permitted us to effectively "scan" the murine genome for genes controlling resistance and susceptibility to leishmanial infections. Five major regions were implicated which, because they show conserved synteny with regions of the human genome, immediately provide candidate gene regions for human disease susceptibility genes. A common intramacrophage niche for leishmanial and mycobacterial pathogens, and a similar spectrum of immune response and disease phenotypes, also led to the prediction that the same genes/candidate gene regions might be responsible for genetic susceptibility to mycobacterial infections such as leprosy and tuberculosis. Indeed, one of the murine genes (Nramp1) was identified for its role in controlling a range of intramacrophage pathogens, including leishmanial, salmonella and mycobacterial infections. In recent studies, multicase families of visceral leishmaniasis, tuberculosis and leprosy, from north-eastern Brazil have been analysed to determine the role of these candidate genes/regions in humans. Complex segregation analysis provides evidence for one or two major genes controlling susceptibility to these diseases in this population. Family-based linkage analyses (e.g., combined segregation and linkage analysis; sib-pair analyses) and transmission disequilibrium testing have been used to examine the role of four regions in disease susceptibility and/or immune response phenotypes. Results to date demonstrate: (1) the major histocompatibility complex (MHC:H-2 in mouse, HLA in humans: mouse chromosome 17/human 6p; candidates class II and class III including tumour necrosis factor alpha/beta genes) shows both linkage to, and allelic association with, leprosy per se, but is only weakly associated with visceral leishmaniasis and shows neither linkage to, nor allelic association with, tuberculosis; (2) no evidence for linkage between NRAMP1, the positionally cloned candidate for the murine macrophage resistance gene Ity/Lsh/Bcg (mouse chromosome 1/human 2q35), and susceptibility to tuberculosis or visceral leishmaniasis; (3) the region of human chromosome 17q (candidates NOS2A, SCYA2-5) homologous with distal mouse chromosome 11 is linked to tuberculosis susceptibility; and (4) the "T helper 2" cytokine gene cluster (proximal murine chromosome 11/human 5p; candidates IL4, IL5, IL9, IRF1, CD14) is not linked to human disease susceptibility for any of the three infections, but shows linkage to and highly significant allelic association with ability to mount an immune response to mycobacterial antigens. The demonstration of an allelic association between IL4 and immune response to mycobacterial antigen may provide a genetic explanation for the inverse association recently demonstrated between delayed hypersensitivity T helper 1 responses to mycobacterial antigen and atopic disorder in Japanese children. These studies demonstrate that the "mouse-to-human" strategy, refined by our knowledge of the human immune response to infection, can lead to the identification of important candidate gene regions in humans.

Infection genomics: Nramp1 as a major determinant of natural resistance to intracellular infections.

The scope of the tuberculosis (TB) epidemic in the world today is enormous, with about 30 million active cases. Current research into preventing the spread of TB is focused on development of new drugs to inactivate Mycobacterium tuberculosis, the causative agent of TB, as well as on identifying the critical steps of host defense to infection with Mycobacteria, which might also yield therapeutic targets. Our infection genomics approach toward the latter strategy has been to isolate and characterize a mouse gene, Bcg (Nramp1), which controls natural susceptibility to infection with Mycobacteria, as well as Salmonella and Leishmania. Through comparative genomics, we have identified the homologous human NRAMP1 gene, alleles of which are now being used for tests of linkage with TB and leprosy.

Cytokine networks with infection: mycobacterial infections, leishmaniasis, human immunodeficiency virus infection, and sepsis.

Distinct cytokine profiles are clearly associated with and relate to the severity of several types of infections. Cytokine networks are apparent with selected human infectious diseases, such as mycobacterial infections (leprosy, tuberculosis), the parasitic infection leishmaniasis, human immunodeficiency virus (HIV) infection, and gram-negative sepsis. Cytokine profiles are determined to some extent by two functional subsets of T lymphocytes, Th1 and Th2. The Th1 cytokines (interferon gamma, interleukin-2 [IL-2], IL-12) enhance cell-mediated immunity, inhibit humoral immunity, and result in protective effect for pathogens that are removed primarily through cell-mediated immunity (Mycobacterium tuberculosis, Mycobacterium leprae, Leishmania). The Th2 cytokines (IL-4, IL-5, IL-10, IL-13) enhance humoral immunity and inhibit cell-mediated immunity, and result in protective effect for pathogens removed primarily through humoral mechanisms. Progression of HIV infection is associated with a switch from a Th1 to a Th2 profile. For sepsis, uncontrolled activation of proinflammatory cytokines (IL-1, tumor necrosis factor-alpha, interferon-gamma) may be a fundamental defect that promotes the detrimental aspects of inflammation, whereas Th2 cytokines may be beneficial in controlling inflammation. Knowledge of basic cytokine immunopharmacology, networks, and relationships with infectious processes will aid clinicians in determining treatment approaches that are likely to be effective.

Serodiagnosis of leishmaniasis.

Leishmaniasis is a spectrum of diseases ranging in severity from cutaneous (CL), post-kala-azar dermal (PKDL), and diffuse cutaneous (DCL) to mucocutaneous (MCL) and visceral (VL) infections that are endemic in 86 tropical and subtropical countries around the world, accounting for 75,000 deaths per year. Different forms of leishmaniases are generally caused by different distinct species of Leishmania having a digenetic life cycle alternating between an aflagellated amastigote form replicative within the macrophages of the host and a flagellated promastigote form that multiplies within the gut of the sandfly. VL, MCL, PKDL, DCL, and CL forms of the disease can be arranged on a priority basis in accordance with the humoral immune responses of host. Generally, the cell-mediated immunity, particularly the delayed-type hypersensitivity to leishmanial antigens, is associated with CL, MCL, PKDL, and cured VL cases. The serodiagnosis of leishmaniasis appears to be an alternative to parasite detection in biopsy samples either by the staining of amastigotes or by culturing the amastigotes, which transform to a promastigote form and replicate. A battery of immunological procedures have been developed or adapted to demonstrate either humoral or cell-mediated immune responses against Leishmania for diagnosis and epidemiological survey. The sensitivity and specificity of such diagnostic methods depend on the type, source, and purity of antigen employed, as some of the leishmanial antigens have common cross-reactive epitopes shared with other microorganisms, particularly Trypanosoma, Mycobacteria, Plasmodia, and Schistosoma. Serodiagnostic techniques for the detection of antileishmanial antibodies have been employed with about 72 to 100, 23 to 90, 83, and 33 to 100% success in VL, CL, MCL, and PKDL patients, respectively. The Leishmanin skin test (LST) is useful to detect MCL and CL, with about 100 and 84% success, respectively. In PKDL, the gradual fall of antileishmanial antibody titer to some extent and the rise of delayed hypersensitivity to the parasite antigen are the characteristic features associated with the chronicity of the disease. The use of whole promastigote as the source of antigens in the direct agglutination test (DAT) and immunofluorescent test (IFAT) gave cross-reactions with the sera of leprosy, tuberculosis, and African trypanosomiasis patients. Again, the use of cell-free extracts of promastigotes generally gave false positive results with the sera of normal human and Chagas' disease, leprosy, tuberculosis, and malaria patients in enzyme-linked immunosorbent assay (ELISA), dot ELISA, immunodiffusion, immunoelectrophoresis, and counter-current immunoelectrophoresis tests.(ABSTRACT TRUNCATED AT 400 WORDS)

Lymphocytes bearing antigen-specific gamma delta T-cell receptors accumulate in human infectious disease lesions.

The majority of T cells bear the T-cell receptor (TCR) alpha beta complex which recognizes foreign antigen peptides only in the context of self major histocompatibility complex (MHC) molecules. Such T cells function in a variety of effector roles and secrete cytokines that mediate the activation and differentiation of other cells in the immune system. Recently, a small subpopulation T cells was found to bear a distinct TCR composed of gamma and delta subunits. In man, TCR gamma delta+ cells are distributed as approximately 5 per cent of the CD3+ cells in all organized lymphoid organs as well as in the skin- and gut-associated lymphoid tissues. Although a limited number of germ-line genes encode the TCR gamma and delta subunits, extensive junctional variation particularly in the delta gene, results in unprecedented diversity for this receptor. The nature of the specificity and immunological functions of these T cells remains enigmatic. We report here that in contrast to the normal low frequency of gamma delta-bearing cells in lymphoid tissues, peripheral blood, or normal skin, the frequency is increased five to eightfold in particular granulomatous reactions of leprosy. TCR gamma delta+ lymphocyte lines from these leprosy skin lesions proliferate in vitro specifically to mycobacterial antigens. This reactivity to foreign antigens appears to require presentation in the context of self-molecules. Moreover, culture supernatants from activated gamma delta T lymphocytes induce adhesion and aggregation of bone-marrow monocytes in the presence of granulocyte monocyte-colony stimulating factor (CSF), suggesting that products of gamma delta-bearing T cells may play a role in the immune response, possibly by stimulating granuloma formation.

Differential recognition of Leishmania aethiopica antigens by lymphocytes from patients with local and diffuse cutaneous leishmaniasis. Evidence for antigen-induced immune suppression.

Data are presented to suggest that differential Ag expression by parasites derived from diffuse (DCL) vs local (LCL) cutaneous leishmaniasis patients may be responsible for the Ag-specific anergy seen in DCL patients. The evidence suggests that promastigotes derived from DCL patients express epitopes which preferentially stimulate suppressor activities in DCL patients. These determinants appear to be expressed less, if at all by promastigotes derived from LCL patients. The Ag-specific suppression or nonresponsiveness which dominates the immune response in DCL patients during an active infection can be abrogated by drug treatment or removal of live DCL parasites, which suggests that Ag-induced regulatory cells, probably of T cell lineage, are most likely responsible for the nonresponsiveness seen in untreated DCL patients. Thus the mechanisms of immune regulation operating in this disease differ from that of lepromatous leprosy where the specific unresponsiveness (anergy) is irreversible even after successful treatment.

Gamma interferon production induced by antigens in patients with leprosy and American cutaneous leishmaniasis.

In this study, we measured gamma interferon production in mononuclear cell cultures from patients with diverse forms of leprosy and American cutaneous leishmaniasis. We studied patients with lepromatous, borderline lepromatous, borderline, and borderline tuberculoid forms of leprosy, as well as a Mitsuda-negative contact. In leishmaniasis we studied patients with localized cutaneous, mucocutaneous, and diffuse cutaneous forms of the disease. High correlation was observed between gamma interferon production and lymphocyte proliferation assays in both diseases. Resistant forms of both diseases showed significant reactivity, while the severe progressive forms were characterized by insignificant responses in both assays. Localized cutaneous leishmaniasis is characterized by variability in gamma interferon production, which may be of prognostic value in longitudinal studies.

The expression of a gamma interferon-induced protein (IP-10) in delayed immune responses in human skin.

Our knowledge of the induction of new molecules by IFN-gamma has led to the characterization of IP-10 and the preparation of a monospecific, polyclonal antibody. Using this reagent we have now examined inflammatory states occurring in human skin and used immunocytochemical staining for the expression of both Ia and IP-10 determinants. After evoking a delayed-type response to purified protein derivative of tuberculin (PPD), we noted the presence of IP-10 in dermal macrophages and endothelial cells. Intense staining of the basal layer of epidermal keratinocytes was prominent at 41 h, and by 1 wk the entire epidermis was staining. The comparison of the amount of IP-10 secreted by keratinocytes vs. macrophages, fibroblasts, and endothelial cells revealed that keratinocytes were by far the major producers of this molecule. The expression of Ia occurred in conjunction with IP-10. The injection of rIFN-gamma mimicked many of the features of the PPD response, including the expression of both Ia and IP-10 by epidermal keratinocytes. Coexpression was also found in the natural lesions of tuberculoid leprosy and cutaneous Leishmaniasis. However, it was absent in lepromatous leprosy, a state where activated T lymphocytes are not present. We suggest that the local production of IFN-gamma by T cells of the dermal infiltrate induces IP-10 formation in both the dermis and epidermis. IP-10 and Ia then serve as specific markers of immune IFN and its possible influence on effector cells of the cell mediated immune response.