Rainfall and sea level drove the expansion of seasonally flooded habitats and associated bird populations across Amazonia

Spatial arrangement of distinct Amazonian environments through time and its effect on specialized biota remain poorly known, fueling long-lasting debates about drivers of biotic diversification. We address the late Quaternary sediment deposition that assembled the world's largest seasonally flooded ecosystems. Genome sequencing was used to reconstruct the demographic history of bird species specialized in either early successional vegetation or mature floodplain forests. Sediment deposition that built seasonally flooded habitats accelerated throughout the Holocene (last 11,700 years) under sea level highstand and intensification of the South American Monsoon, at the same time as global increases in atmospheric methane concentration. Bird populations adapted to seasonally flooded habitats expanded due to enlargement of Amazonian river floodplains and archipelagos. Our findings suggest that the diversification of the biota specialized in seasonally flooded habitats is coupled to sedimentary budget changes of large rivers, which rely on combined effects of sea level and rainfall variations.

This study found that millennial periods of higher rainfall combined with rising sea level enhanced sediment accumulation in Amazonian rivers valleys. This fuelled synchronous expansion of vegetation adapted to seasonally flooded substrates and its specialized bird populations, showing how global climate changes can affect specific Amazonian species.

Silver nanoprisms as plasmonic enhancers applied in the photodynamic inactivation of Staphylococcus aureus isolated from bubaline mastitis

Mastitis is a bacterial infection that affects all lactating mammals, and in dairy cattle, it leads to a reduction in their milk production and, in worse cases, it may lead to animal death. One viable therapeutic modality for overcoming bacterial resistance can be photodynamic inactivation (PDI), a therapeutic modality for bacterial infection treatment. One of the main factors that can lead to an efficient PDI process is the association of metallic nanoparticles in the close vicinity of photosensitizers, which has shown promising results due to localized surface plasmon resonance phenomena. In this work, methylene blue (MB) molecules were associated with Ag prismatic nanoplatelets (AgNPrs) to use as PDI photosensitizer against Staphylococcus aureus isolated from bubaline mastitis. The optical plasmonic activity of AgNPrs was tuned to the MB absorption region (600-700 nm) by inducing their growth into prismatic shapes by a seed-mediated procedure, using poly (sodium 4-styrene sulfonate) as the surfactant. A simulation on the plasmonic properties of the nanoprisms, applying particle size within the dimensions determined by TEM image analysis (d = 32 ± 6 nm), showed a 30 % increase of the incident field on the prismatic tips. Photodynamic results showed that the electrostatic AgNPr-MB conjugates promoted enhancement (ca. 15 %) of the reactive oxygen species production. Besides, PDI mediated by AgNPrs-MB led to the complete inactivation of the mastitis S. aureus strain after 6 min inactivation, in contrast to PDI mediated by MB, which reduced less than a 0.5 bacterial log. Thus, the results show this plasmonic enhanced photodynamic tool's potential to be applied in the inactivation of multi-resistant bacterial strains.

Phylogeny of the Trichogramma endosymbiont Wolbachia, an alpha-proteobacteria (Rickettsiae)

Wolbachia (Hertig) endosymbionts are extensively studied in a wide range of organisms and are known to be transmitted through the egg cytoplasm to the offsping. Wolbachia may cause several types of reproductive modifications in arthropods. In Trichogramma species, parthenogenesis-inducing Wolbachia bacteria allow females wasps to produce daughters from unfertilized eggs and these bacteria are present in at least 9% of all Trichogramma species. Phylogenetic studies have led to the subdivision of the Wolbachia clade in five supergroups (A, B, C, D and E) and Wolbachia from Trichogramma belong to supergroup B. Here, using the wsp gene, four groups of Wolbachia that infect Trichogramma species were distinguished and the addition of a new group "Ato" was suggested due to the addition of Wolbachia from Trichogramma atopovirilia (Oatman and Platner). Specific primers were designed and tested for the "Ato" group. Seventy-five percent of all evaluated Wolbachia strains from Trichogramma fell within "Sib" group.

Expression of glyceraldehyde 3-phosphate dehydrogenase is enhanced in Leishmania spp naturally resistant to nitric oxide

Leishmania spp are the causative agents of a spectrum of diseases termed leishmaniasis that affect mammals, including humans and dogs. Although reactive nitrogen species are employed in the control of parasitism by the immune system, it is known that Leishmania can withstand this oxidative stress. As the mechanism by which these species are resistant to nitric oxide (NO) is poorly understood, the main objective of this study was to evaluate the expression of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in Leishmania amazonensis and Leishmania chagasi promastigotes showing natural resistance to NO. GAPDH transcript levels were quantified by real-time polymerase chain reaction amplification, and GAPDH activity (assessed by levels of NADH oxidation) was measured by spectrophotometry. The level of nitration in total protein was assessed by immunoblotting. The results demonstrated an increase in GAPDH expression in resistant isolates of both species compared to susceptible isolates. The increase in GAPDH expression led to an increase in the activity of GAPDH in L. amazonensis human isolates resistant to NO. The pattern of protein nitration did not differ between sensitive and resistant isolates. Our results suggest that changes in expression of GAPDH may be responsible, at least in part, to natural resistance to NO found in human and canine Leishmania spp.

Leishmania chagasi naturally resistant to nitric oxide isolated from humans and dogs with visceral leishmaniasis in Brazil

Nitric oxide (NO) plays an important role as a leishmanicidal agent in murine macrophages. NO resistant Escherichia coli and Mycobacterium tuberculosis have been associated with poor outcomes of their resulting diseases. NO resistant Leishmania braziliensis has also been identified and exacerbates the clinical course of human leishmaniasis. We report, for the first time, natural resistance of Leishmania chagasi promastigotes to NO. These parasites were isolated from humans and dogs with visceral leishmaniasis. We also demonstrate that this resistance profile was associated with a greater survival capacity and a greater parasite burden in murine macrophages, independent of activation and after activation by IFN-γ and LPS.

Differential immune regulation of activated T cells between cutaneous and mucosal leishmaniasis as a model for pathogenesis

Cutaneous (CL) and mucosal leishmaniasis (ML) are characterized by a predominant type 1 immune response (IFN-gamma and TNF-alpha production) and strong inflammatory response in the lesions with few parasites. This exacerbated type 1 response is more evident in ML as compared to CL. Our main hypothesis is that a differential immune regulation of T cell activation leads to over reactive T cells in ML. In the present study, we investigated immunological factors that could explain the mechanisms behind it by comparing some immune regulatory mechanisms between ML and CL patients: frequency of cells expressing co-stimulatory molecules, apoptotic markers, T cell activation markers; and ability of neutralizing antibodies to IL-2, IL-12 and IL-15 do down-regulate IFN-gamma production in leishmania antigen-stimulated peripheral blood mononuclear cells (PBMC). Interestingly, in CL anti-IL-2 and anti-IL-15 significantly suppressed antigen-specific IFN-gamma production, while in ML only anti-IL-2 suppressed IFN-gamma production. Finally, higher frequency of CD4+ T cells expressing CD28-, CD69+ and CD62L(low) were observed in ML as compared to CL. These data indicate that an exacerbated type 1 response in ML is differentially regulated and not appropriately down modulated, with increased frequencies of activated effectors T cells, maintaining the persistent inflammatory response and tissue damage observed in ML.

Antigen specific correlations of cellular immune responses in human leishmaniasis suggests mechanisms for immunoregulation

Regulation of the immune response directed against Leishmania is critical for the establishment of effective control of the disease. It is likely that some types of immune responses directed against Leishmania can lead to more severe clinical forms of leishmaniasis causing a poor control of the pathogen and/or pathology, while others lead to resolution of the infection with little pathology as in cutaneous leishmaniasis. To gain a better understanding of the possible role that subpopulations of T cells, and their associated cytokines have on disease progression and/or protective immune responses to L. braziliensis infection, a detailed study of the frequency of activated and memory T cells, as well as antigen specific, cytokine producing T cells was carried out. Following the determination of cytokine producing mononuclear cell populations in response to total Leishmania antigen (SLA), and to the recombinant antigen LACK, correlation analysis were performed between specific cytokine producing populations to identify models for cellular mechanisms of immunoregulation in human cutaneous leishmaniasis. These studies have shown: (1) a positive correlation between ex vivo CD45RO frequencies and antigen specific cytokine (IFN-gamma or IL-10) producing cells; (2) a negative correlation between ex vivo CD69 expression and the frequency of IFN-gamma producing cells; (3) a positive correlation amongst SLA specific, IFN-gamma or TNF-alpha and IL-10 producing lymphocytes with one another; and (4) a higher frequency of IL-10 producing, parasite specific (anti-SLA or anti-LACK), lymphocytes are correlated with a lower frequency of TNF-alpha producing monocytes, demonstrating an antigen specific delivery of IL-10 inducing negative regulation of monocyte activity.

Multiclonal Leishmania braziliensis population structure and its clinical implication in a region of endemicity for American tegumentary leishmaniasis

In Corte de Pedra (CP), northeastern Brazil, Leishmania braziliensis causes three distinct forms of American tegumentary leishmaniasis (ATL). To test the hypothesis that strain polymorphism may be involved in this disease spectrum and accurately characterize the parasite population structure in CP, we compared one L. major, two non-CP L. braziliensis, one CP L. amazonensis, and 45 CP L. braziliensis isolates, obtained over a 10-year period from localized cutaneous, mucosal, and disseminated leishmaniasis patients, with randomly amplified polymorphic DNA (RAPD). Electrophoretic profiles were mostly unique across species. All typing protocols revealed polymorphism among the 45 CP L. braziliensis isolates, which displayed eight different RAPD patterns and greater than 80% overall fingerprint identity, attesting to the adequacy of the tools to assess strain variability in CP's geographically limited population of parasites. The dendrogram based on the sum of RAPD profiles of each isolate unveiled nine discrete typing units clustered into five clades. Global positioning showed extensive overlap of these clades in CP, precluding geographic sequestration as the mechanism of the observed structuralization. Finally, all forms of ATL presented a statistically significant difference in their frequencies among the clades, suggesting that L. braziliensis genotypes may be accompanied by specific disease manifestation after infection.

IgG anti-IgE autoantibodies in visceral leishmaniasis

Procedures for IgG depletion in visceral leishmaniasis (VL) and schistosomiasis sera using Sepharose-protein G beads also deplete IgE. In this study, the presence of IgG anti-IgE autoantibodies in sera from patients with VL (n = 10), and hepatic-intestinal schistosomiasis (n = 10) and from healthy individuals (n = 10) was investigated. A sandwich ELISA using goat IgG anti-human IgE to capture serum IgE and goat anti-human IgG peroxidase conjugate to demonstrate the binding of IgG to the IgE captured was performed. VL sera had higher titers (p < 0.05) of IgG anti-IgE autoantibodies (OD = 2.01 +/- 0.43) than sera from healthy individuals (OD = 1.35 +/- 0.16) or persons infected with Schistosoma mansoni (OD = 1.34 +/- 0.18). The immunoblotting carried out with eluates from Sepharose-protein G beads used to deplete IgG from these sera and goat anti-human IgE peroxidase conjugate, showed a similar pattern of bands, predominating the 75 kDa epsilon-heavy chain and also polypeptides resulting from physiological enzymatic digestion of IgE. A frequent additional band immediately above 75 kDa was observed only in VL sera.

[Evaluation of the sensitization power of Montenegro skin test]

The Montenegro skin test, used to diagnose cutaneous leishmaniasis, is now being considered to detect immunogenicity after vaccination. In this study, we evaluated the ability of this test to induce immune response and IFN-g production in subjects not previously exposed to Leishmania. The Montenegro skin test was performed using antigens of L. amazonensis produced by our laboratory (group I) or by FIOCRU-RJ (group II). At day 30, 33% of the subjects from group I and 42% from group II were positive, compared to 67% from group I and 50% from group II at day 90. IFN-y was detected in 56 % of subjects from group I and 17% from group II at day 30 (169+/-309 and 11+/-36pg/ml) and in 67% from group I and 58% from group II by day 360 (69+/-107 and 18+/-20pg/ml). These data demonstrate that the Montenegro skin test induces not only a delayed hypersensitivity reaction, but also IFN-y production.

Flow cytometric determination of cellular sources and frequencies of key cytokine-producing lymphocytes directed against recombinant LACK and soluble Leishmania antigen in human cutaneous leishmaniasis

Leishmaniasis, caused by infection with the protozoan parasite Leishmania, affects millions of individuals worldwide, causing serious morbidity and mortality. This study directly determined the frequency of cells producing key immunoregulatory cytokines in response to the recombinant antigen Leishmania homolog of receptors for activated kinase C (LACK) and soluble leishmania antigen (SLA), and it determined relative contributions of these antigens to the overall cytokine profile in individuals infected for the first time with Leishmania braziliensis. All individuals presented with the cutaneous clinical form of leishmaniasis and were analyzed for proliferative responses to LACK antigen and SLA, frequency of lymphocyte subpopulations (analyzed ex vivo), and antigen-induced (LACK and SLA) cytokine production at the single-cell level (determined by flow cytometry). The following were determined. (i) The Th1-type response previously seen in patients with cutaneous leishmaniasis is due to gamma interferon (IFN-gamma) production by several different sources, listed in order of contribution: CD4(+) T lymphocytes, CD4(-), CD8(-) lymphocytes, and CD8(+) T lymphocytes. (ii) SLA induced a higher frequency of lymphocytes producing IFN-gamma and tumor necrosis factor alpha (TNF-alpha) than did LACK. (iii) LACK induced an activation of monocyte populations as reflected by an increased percentage of CD14-positive cells. (iv) Neither SLA nor LACK induced detectable frequencies of cells producing interleukin-4 (IL-4) or IL-5. These data demonstrated a multifaceted immune response to SLA in human leishmaniasis involving Th1 CD4(+) T lymphocytes (IFN-gamma(+) and IL-10(-)/IL-4(-)), Tc1 CD8(+) T cells (IFN-gamma(+), and IL-10(-)/IL-4(-)), and a high frequency of TNF-alpha-producing lymphocytes. Moreover, it was determined that the recombinant antigen LACK acts as a weak inducer of Th1-type lymphocyte responses compared to SLA.

Down-regulation of Th1 type of response in early human American cutaneous leishmaniasis

This study examined the T cell responses in the early phase of Leishmania braziliensis infection. Cytokine profiles, lymphoproliferative responses, and skin test results in 25 patients with early cutaneous leishmaniasis (ECL; illness duration <60 days) were compared with those in persons with late cutaneous leishmaniasis (LCL; illness duration >2 months). Absent or low lymphoproliferative responses were observed in 8 (32%) of 25 patients and an absence of interferon (IFN)-gamma production in 9 (41%) of 22 patients prior to therapy. IFN-gamma production in ECL (mean +/- SD) was lower than in LCL (293+/-346 vs. 747+/-377 pg/mL, respectively; P<.01). In contrast, interleukin (IL)-10 production in ECL (mean +/- SD) was higher than in LCL (246+/-56 vs. 50+/-41 pg/mL, respectively; P<.01). Restoration of lymphoproliferative responses and IFN-gamma production was achieved when monoclonal antibody to IL-10 or IL-12 was added to the cultures. These results show that T cell responses during early-phase infection are down-regulated by IL-10 and may facilitate parasite multiplication.

Detection of specific IgE antibodies in parasite diseases

Activation of Th1 or Th2 cells is associated with production of specific immunoglobulin isotypes, offering the opportunity to use antibody measurement for evaluation of T cell function. Schistosomiasis and visceral leishmaniasis are diseases associated with Th2 activation. However, an IgE response is not always detected in these patients. In the present study we evaluated specific IgE antibodies to S. mansoni and L. chagasi antigens by ELISA after depletion of serum IgG with protein G immobilized on Sepharose beads or RF-absorbent (purified sheep IgG antibodies anti-human IgG). In schistosomiasis patients, specific IgE to SWAP antigen was demonstrable in only 10 of 21 patients (48%) (mean absorbance +/- SD = 0.102 +/- 0.195) when unabsorbed serum was used. Depletion of IgG with protein G increased the number of specific IgE-positive tests to 13 (62%) and the use of RF-absorbent increased the number of positive results to 20 (95%) (mean absorbances +/- SD = 0.303 +/- 0. 455 and 0.374 +/- 0.477, respectively). Specific IgE anti-L. chagasi antibodies were not detected in unabsorbed serum from visceral leishmaniasis patients. When IgG was depleted with protein G, IgE antibodies were detected in only 3 (11%) of 27 patients, and the use of RF-absorbent permitted the detection of this isotype in all 27 visceral leishmaniasis sera tested (mean absorbance +/- SD = 0.104 +/- 0.03). These data show that the presence of IgG antibodies may prevent the detection of a specific IgE response in these parasite diseases. RF-absorbent, a reagent that blocks IgG-binding sites and also removes rheumatoid factor, was more efficient than protein G for the demonstration of specific IgE antibodies.

Anti-leishmanial IgE antibodies: a marker of active disease in visceral leishmaniasis

Visceral leishmaniasis (VL) is characterized by a depression of the T helper cell type 1 immune response. Although mRNA expression for interleukin-4 (IL-4) is observed, evidence of the role of this cytokine in the pathogenesis of VL has been lacking. Since IL-4 is involved in IgE synthesis, we measured the total IgE and Leishmania antigen-specific IgE antibody levels in sera from patients with VL. Specific IgE antibodies detected by an ELISA technique after absorbing the sera with purified sheep IgG anti-human IgG were found in all 23 patients with VL and were not detected in subjects with subclinical Leishmania chagasi infection (n = 10), Chagas' disease (n = 10), atopic patients (n = 10), and healthy controls (n = 10). Levels of Leishmania-specific IgE (optical density values) before and after treatment were 0.100 +/- 0.03 (mean +/- SD) and 0.028 +/- 0.002, respectively (P < 0.05). These results indicate that a specific IgE response is useful in the diagnosis of active disease and to evaluate response to treatment.

Cytokine profile and pathology in human leishmaniasis

The clinical spectrum of leishmaniasis and control of the infection are influenced by the parasite-host relationship. The role of cellular immune responses of the Th1 type in the protection against disease in experimental and human leishmaniasis is well established. In humans, production of IFN-gamma is associated with the control of infection in children infected by Leishmania chagasi. In visceral leishmaniasis, an impairment in IFN-gamma production and high IL-4 and IL-10 levels (Th2 cytokines) are observed in antigen-stimulated peripheral blood mononuclear cells (PBMC). Moreover, IL-12 restores IFN-gamma production and enhances the cytotoxic response. IL-10 is the cytokine involved in down-regulation of IFN-gamma production, since anti-IL-10 monoclonal antibody (mAb) restores in vitro IFN-gamma production and lymphoproliferative responses, and IL-10 abrogates the effect of IL-12. In cutaneous and mucosal leishmaniasis, high levels of IFN-gamma are found in L. amazonensis-stimulated PBMC. However, low or absent IFN-gamma levels were observed in antigen-stimulated PBMC from 50% of subjects with less than 60 days of disease (24 +/- 26 pg/ml). This response was restored by IL-12 (308 +/- 342 pg/ml) and anti-IL-10 mAb (380 +/- 245 pg/ml) (P < 0.05). Later during the disease, high levels of IFN-gamma and TNF-alpha are produced both in cutaneous and mucosal leishmaniasis. After treatment there is a decrease in TNF-alpha levels (366 +/- 224 pg/ml before treatment vs 142 +/- 107 pg/ml after treatment, P = 0.02). Although production of IFN-gamma and TNF-alpha might be involved in the control of parasite multiplication in the early phases of Leishmania infection, these cytokines might also be involved in the tissue damage seen in tegumentary leishmaniasis.

Azurocidin, a natural antibiotic from human neutrophils: expression, antimicrobial activity, and secretion

The azurophil granules of human PMN contain four antibiotic proteins, the serprocidins, which have extensive homology to one another and to serine proteases. Azurocidin, a member of this family, is a 29-kDa glycoprotein with broad spectrum antimicrobial activity and chemotactic activity toward monocytes. Insect cells transfected with a baculovirus vector carrying azurocidin cDNA produced a recombinant azurocidin protein. We purified the recombinant azurocidin protein from the culture medium of the infected cells and showed that it retained the antimicrobial activity of the native neutrophil-derived molecule. In addition, we present evidence that a 49-amino-acid region of the recombinant azurocidin protein is required for its secretion from insect cells.

Characterization of a recombinant proteinase 3, the autoantigen in Wegener's granulomatosis and its reactivity with anti-neutrophil cytoplasmic autoantibodies

Using the baculovirus/insect cells system, we have expressed a recombinant proteinase 3 (PR3) -- the neutrophil-derived serine protease autoantigen in Wegener's granulomatosis -- as a glycosylated intracellular and membrane-associated protein. Oligosaccharides accounted for the difference in molecular weights between recombinant (34 kDa) and neutrophil-PR3 (29 kDa). Whereas rabbit-anti-PR3 IgG recognized both recombinant and neutrophil-derived PR3, autoantibodies from Wegener patient sera recognized only neutrophil-derived PR3. Although oligosaccharides were not involved in PR3 epitope recognition, autoantibodies did not recognize the amino acid primary structure of recombinant PR3. Improper disulfide bond formation and/or lack of post-translational events in insect cells, may affect the conformation and/or lack of post-translational events in insect cells, may affect the conformation of PR3, precluding its reactivity with sera from WG patients.

Biological behavior of Leishmania amazonensis isolated from humans with cutaneous, mucosal, or visceral leishmaniasis in BALB/C mice

Leishmania amazonensis causes a wide spectrum of disease in humans. In this study, we evaluated BALB/c mice infected with five strains of L. amazonensis isolated from patients with either cutaneous, mucosal, or visceral leishmaniasis. Mice infected with cutaneous and mucosal isolates developed ulcerating footpad lesions with parasite-loaded macrophages and extensive tissue destruction. Skin metastases, early dissemination of parasites to the spleen, and high anti-Leishmania antibody levels were also noted. Mice infected with L. amazonensis strains isolated from patients with visceral disease had a controlled infection, with small footpad lesions with mononuclear cell infiltration, few infected macrophages, and granuloma formation. They had no skin metastases, delayed dissemination of the parasite to the spleen, lower levels of IgG and higher levels of IgG2a against L. amazonensis. These findings demonstrate an unexpected resistance of BALB/c mice to the infection with L. amazonensis isolated from patients with visceral leishmaniasis. This resistance seems to be due to differences in these parasites that may be related to the altered course of the disease in humans and in isogenic BALB/c mice.

Characterization of the immune response in subjects with self-healing cutaneous leishmaniasis

In patients with cutaneous leishmaniasis in areas of Leishmania braziliensis transmission, ulcers may heal without therapy. In the present study, we evaluated the T cell responses of 10 subjects who two years earlier had a rapidly (less than three months) self-healing cutaneous disease. The immunologic responses of these cases were determined by intradermal skin test, measurements of antibodies, lymphocyte proliferative responses, and interferon-gamma (IFN-gamma) production in cultures stimulated with Leishmania antigens. These data were compared with those observed in 10 other patients with active cutaneous and mucosal leishmaniasis. Evidence of strong lymphocyte blastogenesis and IFN-gamma production was observed in eight of 10 patients with self-healing cutaneous leishmaniasis, with stimulation indices ranging from 32 to 506, and IFN-gamma levels ranging from 500 to 2,900 pg/ml. The mean +/- SD stimulation index of the lymphocyte proliferative responses (288 +/- 247) and the mean +/- SD of IFN-gamma production after stimulation with Leishmania antigen (970 +/- 960 pg/ml) in subjects with self-healing cutaneous leishmaniasis were similar (P > 0.05) to those observed in patients with mucosal disease (stimulation index = 308 +/- 282 and IFN-gamma level = 838 +/- 819 pg/ml). These responses were higher (P < 0.01) than those observed in patients with active cutaneous leishmaniasis (stimulation index = 50 +/- 82 and IFN-gamma level = 264 +/- 336 pg/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Increased serum HLA class I molecule levels in elderly human responders to influenza vaccination

Increased cell surface expression and serum levels of HLA class I molecules have been shown to occur in normal elderly humans. Elderly subjects (65 years and older) generally also have a poorer response to influenza vaccine than younger adults. Some 30 to 40% of elderly subjects do not respond to influenza vaccination. Sera from 20 elderly subjects with a positive response to influenza vaccine (HAI antibody titer > 40) and 20 subjects who did not respond (HAI antibody titer < 40) were randomly selected and the levels of soluble HLA class I molecules determined before and after vaccination. The subjects who responded had higher serum HLA class I levels both before and after vaccination than did non-responders. Two weeks after vaccination non-responders showed similar serum HLA class I levels (1.78 mg/ml +/- 0.62) as compared to prevaccination levels (1.73 mg/ml +/- 0.49). The responders showed significantly higher levels of soluble HLA class I molecules following vaccination (2.64 mg/ml +/- 0.99) as compared to pre-vaccination (2.08 mg/ml +/- 0.85, p = 0.00001). Our results suggest that measuring soluble HLA class I molecules in the serum may be useful in assessing the adequacy of response to influenza vaccination in the elderly population.

Antibiotic peptides and serine protease homologs in human polymorphonuclear leukocytes: defensins and azurocidin

The azurophil granule, a specialized lysosome of neutrophils, contains two families of antimicrobial proteins, each with four members. They are the defensins, comprising human neutrophil protein 1, -2, -3 and -4, on the one hand and the serprocidins, comprising cathepsin G, elastase, proteinase 3 and azurocidin, on the other. Defensins appear to contribute to mammalian as well as invertebrate immunity. Recent studies show that defensins and structurally related peptides are found not only in phagocytes but also in intestinal and respiratory cells. Aside from their antibiotic function, members of the defensin family may also act as hormonal agents. Within the serprocidin family the genes encoding the novel antibiotics and serine protease homologs azurocidin and proteinase 3 have been identified recently.

Correlation between cell-mediated immunity and degree of infection in subjects living in an endemic area of schistosomiasis

Cell-mediated immunity to Schistosoma mansoni antigens, unrelated antigens and mitogens was evaluated in 50 subjects with the same degree of exposure to infection living in an endemic area of schistosomiasis. The degree of infection, assessed by the number of eggs/g of stool, was variable in this population (0-5604), suggesting differences in susceptibility to infection. Absence of lymphoproliferative response was observed in 56% of this group, despite having a response to purified protein derivative of tuberculin (PPD) and tetanus toxoid (TT) antigens and to pokeweed mitogen. The 50 subjects were divided into two groups, according to their degree of infection. The lymphoproliferative responses to schistosomula and adult worm antigens in the group with a low degree of infection (< 400 eggs/g of stool) were higher than the ones documented in patients with a high degree of infection (> 400 eggs/g of stool), and these differences were statistically significant (p < 0.001). An inverse correlation between the lymphocyte proliferation in response to S. mansoni antigens and the degree of infection was also observed (p = 0.02), indicating that subjects with a lower degree of infection have a higher lymphoproliferative response to schistosomula and adult worm antigens. No differences in the lymphocyte reactivity to other antigens (PPD and TT) were detected in these groups. An impairment of interferon-gamma in vitro production was observed when the lymphocytes from these subjects were stimulated with S. mansoni adult worm antigen, although they produced gamma interferon in response to phytohemagglutinin.

Complementary DNA sequence of human neutrophil azurocidin, an antibiotic with extensive homology to serine proteases

Human neutrophils contain in their azurophil granules four antibiotic proteins with extensive homology to serine proteases, collectively termed serprocidins. Azurocidin is the only member of the group that lacks proteolytic activity. Using a monospecific antibody, we isolated from human bone marrow a cDNA encoding the complete azurocidin protein in its mature form, along with an N-terminal 24 residue hydrophobic peptide. The N-terminal third of the mature protein sequence contains a cluster of positively charged amino acid residues, many of which are predicted to be surface exposed. The primary sequence is highly homologous to elastase, proteinase 3, cathepsin G, T-cell granzymes and other serine proteases. However, azurocidin has Gly for Ser and Ser for His substitutions in the catalytic triad. Southern blot analysis of human genomic DNA suggests the existence of a single azurocidin coding sequence.

Tumor necrosis factor (cachectin) in human visceral leishmaniasis

High tumor necrosis factor-alpha (TNF alpha) levels were present in the serum of 24 of 28 active visceral leishmaniasis (VL) patients (142.9 +/- 113.9 pg/ml, mean +/- SD), whereas levels were not elevated in 26 of 30 patients with cryptic leishmanial infection (16 asymptomatic, 4 with self-healing subclinical infection, and 10 posttreatment VL cases). Serum TNF alpha levels were also not elevated in 15 normal volunteers (11.3 +/- 15.6 pg/ml) and in 10 patients with tegumentary leishmaniasis (19.1 +/- 10.8 pg/ml). Leishmanial infection of human monocyte-derived macrophages enhanced the basal TNF alpha production by these cells, and this effect was further potentiated by treatment with recombinant interferon-gamma. After effective treatment of VL patients, serum TNF alpha levels dropped rapidly (129 +/- 112 vs. 9 +/- 13 pg/ml in 10 days), even before clinical parameters such as spleen size or parasitism, white blood cell count, or levels of hemoglobin returned to normal values. On the other hand, patients unresponsive to treatment remained with elevated levels (276 +/- 69 vs. 155 +/- 71 pg/ml in 10 days). Thus, serum TNF alpha levels in VL patients are a good parameter to monitor in determining host response to therapy.

[Emission microspectrometric study of the amalgam restoration-tooth interface]

Optical Emission Microspectroscopy was used to identify the corrosion products in the amalgam tooth interface with and without cavity varnish use in different times. The factor time determined new chemical elements in the older specimens. A major mercury concentration was found in the restoration interface which used cavity varnish, at the initial twenty-four hours. The first corrosion product had the tin in its composition, possibly from the degradation of 2 phase.

Evaluation of T-cell subsets in the lesion infiltrates of human cutaneous and mucocutaneous leishmaniasis

We have characterized the T-lymphocytes in the skin lesions of 10 patients with cutaneous leishmaniasis and in the nasal lesions of seven patients with mucosal leishmaniasis, with the immunoperoxidase and monoclonal antibody techniques. There was predominance of cells with helper phenotype (Leu 3A+ 3B) over suppressor phenotype (Leu 2a) in the lesions of both groups. The helper/suppressor (H/S) ratio in the skin lesions was 1.6 +/- 0.5 and in the nasal lesions of mucosal leishmaniasis was 1.7 +/- 0.8. The H/S ratios in the peripheral blood of patients with cutaneous leishmaniasis (2.1 +/- 0.8) and in patients with mucosal leishmaniasis (1.6 +/- 0.8) were comparable and similar to the ratios in the skin and nasal biopsies. The percentage of T-cells and macrophages expressing the Dr antigen in the cutaneous group (69.5 +/- 13.7) was not significantly different from the mucosal patients (90.3 +/- 5.7). We conclude that the immunopathology of the skin lesions in cutaneous leishmaniasis is similar to the nasal lesions of mucosal leishmaniasis.