TLRs may contribute to the progression of rheumatoid arthritis through recognition of microbial or hostderived ligands found in arthritic joints. Here, we show that TLR2 and TLR4, but not TLR9, are involved in the pathogenesis of autoimmune arthritis and play distinct roles in the regulation of T cells and cytokines. We investigated the involvement of TLR2, TLR4, and TLR9 in the progression of arthritis using IL-1 receptor antagonist-knockout (IL1rn -/-) mice, which spontaneously develop an autoimmune T cell-mediated arthritis. Spontaneous onset of arthritis was dependent on TLR activation by microbial flora, as germ-free mice did not develop arthritis. Clinical and histopathological evaluation of IL1rn -/-Tlr2 -/-mice revealed more severe arthritis, characterized by reduced suppressive function of Tregs and substantially increased IFN-γ production by T cells. IL1rn -/-Tlr4 -/-mice were, in contrast, protected against severe arthritis and had markedly lower numbers of Th17 cells and a reduced capacity to produce IL-17. A lack of Tlr9 did not affect the progression of arthritis. While any therapeutic intervention targeting TLR2 still seems complicated, the strict position of TLR4 upstream of a number of pathogenic cytokines including IL-17 provides an interesting potential therapeutic target for rheumatoid arthritis.

American tegumentary leishmaniasis is a vectorborne parasitic disease caused by Leishmania protozoans. Innate immune cells undergo long-term functional reprogramming in response to infection or Bacillus Calmette-Gué rin (BCG) vaccination via a process called trained immunity, conferring nonspecific protection from secondary infections. Here, we demonstrate that monocytes trained with the fungal cell wall component b-glucan confer enhanced protection against infections caused by Leishmania braziliensis through the enhanced production of proinflammatory cytokines. Mechanistically, this augmented immunological response is dependent on increased expression of interleukin 32 (IL-32). Studies performed using a humanized IL-32 transgenic mouse highlight the clinical implications of these findings in vivo. This study represents a definitive characterization of the role of IL-32g in the trained phenotype induced by b-glucan or BCG, the results of which improve our understanding of the molecular mechanisms governing trained immunity and Leishmania infection control.

Interleukin 32 (IL-32) is a proinflammatory cytokine, expressed as 9 distinct isoforms. The most active isoform is the predominantly intracellular-functioning IL-32γ. Involvement of IL-32 in infectious diseases is increasingly being appreciated. Production of IL-32 promotes pathways that serve to control bacterial infection, especially those caused by mycobacteria. A similar role for this cytokine is observed in the cellular response to viral infections. In addition to its protective effects against microorganisms, IL-32 is involved in immunopathogenesis of some infectious diseases. In parasitic diseases, it has been demonstrated that this cytokine is induced by Leishmania infection. In this review, we summarize the present data on the role of IL-32 in infectious diseases, highlighting this cytokine as new target for control of infections.

In vitro sensitivity of Leishmania (Viannia) braziliensis and Leishmania (Leishmania) amazonensis Brazilian isolates to meglumine antimoniate and amphotericin B Leishmania (Viannia) braziliensis is the most common species in the Americas and the most important causative agent of cutaneous and mucocutaneous leishmaniasis in Brazil, while Leishmania (Leishmania) amazonensis is the primary etiologic agent of the diffuse cutaneous form of the disease (Lainson & Shaw 1998).The therapeutic arsenal routinely employed to treat patients with leishmaniasis is limited and unsatisfactory. Successful leishmaniasis treatment depends on several aspects such as the immune status of the host, clinical manifestations of the disease and the sensitivity of the causative Leishmania. Widespread resistance to pentavalent antimonials has been identified for Leishmania (L.) donovani in some regions of India and Nepal (Sundar et al. 2000;Rijal et al. 2003). However, only a few studies correlated clinical response with in vitro antimony Tropical Medicine and International Health

BackgroundInterleukin-32 (IL-32) is expressed in lesions of patients with American Tegumentary Leishmaniasis (ATL), but its precise role in the disease remains unknown.Methodology/Principal findingsIn the present study, silencing and overexpression of IL-32 was performed in THP-1-derived macrophages infected with Leishmania (Viannia) braziliensis or L. (Leishmania) amazonensis to investigate the role of IL-32 in infection. We report that Leishmania species induces IL-32γ, and show that intracellular IL-32γ protein production is dependent on endogenous TNFα. Silencing or overexpression of IL-32 demonstrated that this cytokine is closely related to TNFα and IL-8. Remarkably, the infection index was augmented in the absence of IL-32 and decreased in cells overexpressing this cytokine. Mechanistically, these effects can be explained by nitric oxide cathelicidin and β-defensin 2 production regulated by IL-32.ConclusionsThus, endogenous IL-32 is a crucial cytokine involved in the host defense against Leishmania parasites.

Background Leishmania (Viannia) braziliensis has been associated with a broad range of clinical manifestations ranging from a simple cutaneous ulcer to destructive mucosal lesions. Factors leading to this diversity of clinical presentations are not clear, but parasite factors have lately been recognized as important in determining disease progression. Given the fact that the activity of ecto-nucleotidases correlates with parasitism and the development of infection, we evaluated the activity of these enzymes in promastigotes from 23 L. braziliensis isolates as a possible parasite-related factor that could influence the clinical outcome of the disease.Methodology/Principal FindingsOur results show that the isolates differ in their ability to hydrolyze adenine nucleotides. Furthermore, we observed a positive correlation between the time for peak of lesion development in C57BL/6J mice and enzymatic activity and clinical manifestation of the isolate. In addition, we found that L. (V.) braziliensis isolates obtained from mucosal lesions hydrolyze higher amounts of adenine nucleotides than isolates obtained from skin lesions. One isolate with high (PPS6m) and another with low (SSF) ecto-nucleotidase activity were chosen for further studies. Mice inoculated with PPS6m show delayed lesion development and present larger parasite loads than animals inoculated with the SSF isolate. In addition, PPS6m modulates the host immune response by inhibiting dendritic cell activation and NO production by activated J774 macrophages. Finally, we observed that the amastigote forms from PPS6m and SSF isolates present low enzymatic activity that does not interfere with NO production and parasite survival in macrophages.Conclusions/SignificanceOur data suggest that ecto-nucleotidases present on the promastigote forms of the parasite may interfere with the establishment of the immune response with consequent impaired ability to control parasite dissemination and this may be an important factor in determining the clinical outcome of leishmaniasis.

Diffuse cutaneous leishmaniasis (DCL) is characterized by disseminated lesions and the absence of a specific cellular immune response. Here, the immunochemotherapy outcome of a patient with DCL from Amazonian Brazil infected with Leishmania (Leishmania) amazonensis is presented. After several unsuccessful chemotherapy treatment regimens and many relapses, a monthly immunotherapy scheme of L. amazonensis PH8 plus L. (Viannia) braziliensis M2903 monovalent vaccines associated with Bacillus Calmette-Guerin (BCG) was established, one round of which also included an M2903 vaccine associated with intermittent antimonial treatment. Temporary healing of all lesions was achieved, although Leishmania skin tests were negative and interferon gamma was not detected in mononuclear cell cultures stimulated with Leishmania antigens. The frequencies of CD16 (+)CD56(+) NK cells (approximately 2x) and CD14 (+)CD16(+) proinflammatory monocytes (approximately 8x) increased in peripheral blood, and CD56 (+) lymphocytes were found infiltrating the lesions. An association between the increase of the frequency of innate immune system cells and the healing of lesions is shown, suggesting that this protocol of immunotherapy reduced the parasite load and activated NK cells and monocytes.

Pneumococcal surface protein A (PspA) has been considered a potential candidate for human vaccines because of its serotype-independent protective immunity. Nasopharyngeal (NP) pneumococcal colonization is highly prevalent in infants and precedes the invasive disease. Thus, prevention of NP colonization may reduce the burden of pneumococcal disease in children. Scarce information focusing on PspA from pneumococcal carriage in humans is available. We examined the genetic diversity of PspA from NP isolates obtained during an ongoing pneumococcal surveillance study with children. PspA families and clades of 183 communityacquired Streptococcus pneumoniae NP isolates from healthy children (n ‫؍‬ 97) and children with respiratory tract infections (n ‫؍‬ 48), pneumonia (n ‫؍‬ 33), or meningitis (n ‫؍‬ 5) were investigated. Overall, 79.8% (n ‫؍‬ 146) of the pneumococcal isolates were classified as PspA family 1 (35.5%) and family 2 (44.3%), whereas 20.2% of the isolates could not be typed. The distribution of PspA families and clades did not differ significantly according to the clinical status of the children. A dendrogram comparing the genetic relationship between the amino acid sequences of the clade-defining region of PspA from NP strains together with 24 invasive reference strains (GenBank) closely reproduced the profile of the families and clades previously reported for pneumococcal invasive strains. These findings strengthen the idea that the use of PspA as a vaccine antigen may protect children against carriage as well as invasive pneumococcal disease.