Can vaccines against canine visceral leishmaniasis interfere with the serological diagnostics recommended by the Brazilian Ministry of Health? / Vacinas anti-leishmaniose visceral canina podem interferir no diagnóstico sorológico preconizado pelo Ministério da Saúde brasileiro?

ABSTRACT: The objective of the current research was to assess seroconversion in dogs immunized with Leishmune® and Leish Tec® vaccines using rapid chromatographic immunoassay DPP® (Dual Path Platform) (DPP CVL) and enzyme immunoassay (EIE) up to one year after the vaccination protocol. The study sample comprised 28 dogs divided into two groups, each group immunized with an anti-CVL vaccine and clinically monitored for one year through clinical evaluation and laboratory tests. 22 (78.5%) dog were monitored. During the evaluation time (T1-30 days, T2-6 months, and T3-1 year after vaccination) the results for all dogs were negative for CVL, except for one animal vaccinated with Leish tec® that seroconverted in the DPP CVL test at T2. Subsequent examinations of this dog were negative. Our results showed that in a non-endemic area, even at different evaluation times, dogs vaccinated against CVL with Leishmune® or Leish tec® did not seroconvert in the serological protocol used by the Brazilian Ministry of Health (DPP/EIE).

RESUMO: O objetivo deste trabalho foi avaliar a soroconversão em cães imunizados com as vacinas Leishmune® e Leish tec®, através do teste imunocromatográfico rápido DPP® (Dual Path Platform) (DPP LVC) e do ensaio imunoenzimático (EIE) durante um ano após o protocolo vacinal. Trata-se de um estudo onde 28 cães divididos em dois grupos foram imunizados cada um com uma vacina anti - LVC e acompanhados durante um ano através de avaliação clínica e exames laboratoriais. Foi possível acompanhar 22 (78.5%) cães. Nos exames dos tempos 1, 2 e 3 (respectivamente 30 dias, 6 messes e 1 ano após a vacinação) os resultados de todos os cães também foram negativos para LVC, exceto de um cão que recebeu a vacina Leish tec® e soroconverteu no DPP LVC no T2, após 6 meses a vacina. Os exames posteriores deste cão foram negativos. Os resultados do presente estudo demostraram que, em área não endêmica e mesmo em diferentes tempos de avaliação, cães vacinados contra LVC, independente da vacina utilizada, não foram capazes de soroconverter no protocolo utilizado pelo Ministério da Saúde brasileiro (DPP/EIE).

Interaction of an opportunistic fungus Purpureocillium lilacinum with human macrophages and dendritic cells

Introduction Purpureocillium lilacinum is emerging as a causal agent of hyalohyphomycosis that is refractory to antifungal drugs; however, the pathogenic mechanisms underlying P. lilacinum infection are not understood. In this study, we investigated the interaction of P. lilacinum conidia with human macrophages and dendritic cells in vitro. Methods Spores of a P. lilacinum clinical isolate were obtained by chill-heat shock. Mononuclear cells were isolated from eight healthy individuals. Monocytes were separated by cold aggregation and differentiated into macrophages by incubation for 7 to 10 days at 37°C or into dendritic cells by the addition of the cytokines human granulocyte-macrophage colony stimulating factor and interleukin-4. Conidial suspension was added to the human cells at 1:1, 2:1, and 5:1 (conidia:cells) ratios for 1h, 6h, and 24h, and the infection was evaluated by Giemsa staining and light microscopy. Results After 1h interaction, P. lilacinum conidia were internalized by human cells and after 6h contact, some conidia became inflated. After 24h interaction, the conidia produced germ tubes and hyphae, leading to the disruption of macrophage and dendritic cell membranes. The infection rate analyzed after 6h incubation of P. lilacinum conidia with cells at 2:1 and 1:1 ratios was 76.5% and 25.5%, respectively, for macrophages and 54.3% and 19.5%, respectively, for cultured dendritic cells. Conclusions P. lilacinum conidia are capable of infecting and destroying both macrophages and dendritic cells, clearly demonstrating the ability of this pathogenic fungus to invade human phagocytic cells. .

Kinetoplastid membrane protein-11 is present in promastigotes and amastigotes of Leishmania amazonensis and its surface expression increases during metacyclogenesis.

Kinetoplastid membrane protein-11 (KMP-11), a protein present in all kinetoplastid protozoa, is considered a potential candidate for a leishmaniasis vaccine. A suitable leishmaniasis vaccine candidate molecule must be expressed in amastigotes, the infective stage for mammals. However, the expression of KMP-11 in Leishmania amastigotes has been a subject of controversy. We evaluated the expression of this molecule in logarithmic and stationary growth phase promastigotes, as well as in amastigotes, of Leishmania amazonensis by immunoblotting, flow cytometry and immunocytochemistry, using a monoclonal antibody against KMP-11. We found that KMP-11 is present in promastigotes and amastigotes. In both stages, the protein was found in association with membrane structures (at the cell surface, flagellar pocket and intracellular vesicles). More importantly, its surface expression is higher in amastigotes than in promastigotes and increases during metacyclogenesis. The increased expression of KMP-11 in metacyclic promastigotes, and especially in amastigotes, indicates a role for this molecule in the parasite relationship with the mammalian host. The presence of this molecule in amastigotes is consistent with the previously demonstrated immunoprotective capacity of vaccine prototypes based on the KMP-11-coding gene and the presence of humoral and cellular immune responses to KMP-11 in Leishmania-infected humans and animals.

Kinetoplastid membrane protein-11 is present in promastigotes and amastigotes of Leishmania amazonensis and its surface expression increases during metacyclogenesis

Kinetoplastid membrane protein-11 (KMP-11), a protein present in all kinetoplastid protozoa, is considered a potential candidate for a leishmaniasis vaccine. A suitable leishmaniasis vaccine candidate molecule must be expressed in amastigotes, the infective stage for mammals. However, the expression of KMP-11 in Leishmania amastigotes has been a subject of controversy. We evaluated the expression of this molecule in logarithmic and stationary growth phase promastigotes, as well as in amastigotes, of Leishmania amazonensis by immunoblotting, flow cytometry and immunocytochemistry, using a monoclonal antibody against KMP-11. We found that KMP-11 is present in promastigotes and amastigotes. In both stages, the protein was found in association with membrane structures (at the cell surface, flagellar pocket and intracellular vesicles). More importantly, its surface expression is higher in amastigotes than in promastigotes and increases during metacyclogenesis. The increased expression of KMP-11 in metacyclic promastigotes, and especially in amastigotes, indicates a role for this molecule in the parasite relationship with the mammalian host. The presence of this molecule in amastigotes is consistent with the previously demonstrated immunoprotective capacity of vaccine prototypes based on the KMP-11-coding gene and the presence of humoral and cellular immune responses to KMP-11 in Leishmania-infected humans and animals.