Feto-maternal interactions and immunological tolerance of the mother to her semiallogeneic fetus

Pregnancy is a cooperative interaction between the mother and her fetus, allowing survival and normal growth of the fetus. Successful pregnancy remains a fascinating phenomenon as it resists the immunological rules of rejection. Immunological recognition of the fetus is vital for maintenance of gestation. The maternal immune system undergoes changes that lead to tolerance of the fetus. Inadequate recognition of fetal antigens may cause abortion. In fact, fetal cells express paternal alloantigens that are not recognized as foreign by the mother. A special balance between lymphocytes is present at the feto-maternal interface to control the immune response. In addition, placenta! trophoblasts act as a physical barrier and exert an immunoregulatory function. Trophoblast cells regulate the expression of human leucocyte antigens. Dysfunction of these cells leads to morphological and functional alterations of the feto-maternal barrier as well as to recurrent spontaneous abortions. Uterine natural killer cells are appropriate residents of the materno-fetal interface to support the adaptation of the blood vessels of the pregnant uterus and regulate trophoblast invasion into the decidua and myometrium. Cytokines are involved at the feto-placental unit by adapting normal T-cell trafficking and modulating the inflammatory process. This study discusses the complex immunological aspects of immune tolerance and the balance of immunity in pregnancy in terms of the role of the human leucocyte antigen, placental trophoblasts, maternal immunosuppression, immune cells, cytokines and immunoregulatory molecules at the feto-maternal interface

ISG15: leading a double life as a secreted molecule

ISG15 is a well-known intracellular ubiquitin-like molecule involved in ISGylation. However, a recent study has revived the notion first put forward two decades ago that ISG15 is also a secreted molecule. Human neutrophils, monocytes and lymphocytes can release ISG15, even though this protein has no detectable signal peptide sequence. ISG15 has also been found in the secretory granules of granulocytes. The mechanism underlying ISG15 secretion is unknown. Secreted ISG15 acts on at least T and natural killer (NK) lymphocytes, in which it induces interferon (IFN)-gamma production. However, the mechanism by which ISG15 stimulates these cells also remains unclear. ISG15 and IFN-gamma seem to define an innate circuit that operates preferentially, but not exclusively, between granulocytes and NK cells. Inherited ISG15 deficiency is associated with severe mycobacterial disease in both mice and humans. This infectious phenotype probably results from the lack of secreted ISG15, because patients and mice with other inborn errors of IFN-gamma immunity also display mycobacterial diseases. In addition to raising mechanistic issues, the studies described here pave the way for clinical studies of various aspects, ranging from the use of recombinant ISG15 in patients with infectious diseases to the use of ISG15-blocking agents in patients with inflammatory diseases.

Influência de citocininas na micropropagação de Mentha x gracilis Sole / Cytokinin influence on Mentha x gracilis Sole micropropagation

Mentha x gracilis Sole é um híbrido que produz óleos essenciais ricos em monoterpenos. Tendo em vista a propagação clonal desta planta, segmentos nodais provenientes de plantas assépticas, foram cultivados em meio de Murashige e Skoog (MS) suplementado com 0; 0,5; 1,0 e 2,0 µM de cinetina, benzilaminopurina (BAP) ou thidiazuron (TDZ). Após 30 dias, as plantas foram transferidas para meio MS não suplementado com citocinina. Os melhores resultados foram obtidos em meio suplementado com 2 µM de TDZ, mostrando ser método viável para a produção rápida de grande número de mudas. Após a transferência das plantas para a casa de vegetação, as plantas propagadas com TDZ apresentam maior número de tricomas glandulares.

Mentha x gracilis Sole is a hybrid that produces essential oils rich in monoterpenes. Aimed at the clonal propagation of this plant, nodal segments from aseptic plants were cultured in Murashige and Skoog (MSO) medium supplemented with 0; 0.5; 1.0 and 2.0 µM kinetin, benzyl adenine (BAP) or thidiazuron (TDZ). After 30 days, plants were transferred to MOS medium without cytokinin supplementation. The best results were obtained in medium supplemented with 2 µM TDZ, which proved to be a viable method for the rapid production of a large number of seedlings. After transference to the greenhouse, plants propagated with TDZ had a larger number of glandular trichomes.

Perfil da resposta Th1/Th2 no fluido gengival de pacientes portadores de doença inflamatória intestinal com periodontite crônica / Th cell profile in the gingival crevicular fluid from inflammatory bowel disease patients with chronic periodontitis

O objetivo dessa tese foi avaliar a expressão de citocinas Th1 (IL-12 e INFγ), citocinas Th2 (IL-4, IL-6 e IL-10) e das citocinas pró-inflamatórias IL-18, IL-1β e TNFα no fluido gengival de pacientes com periodontite crônica portadores da doença de Crohn (DC), de retocolite ulcerativa idiopática (RCUI) e em indivíduos saudáveis (o grupo controle, GC). Como objetivo secundário, avaliamos a função dos neutrófilos no fluido gengival desses pacientes através da mensuração das metaloproteinases da matriz -8, -9 (MMP-8 e MMP-9) e da atividade da elastase. Quinze pacientes com DC (idade média 38.2 ± 11.4 anos), 15 pacientes com RCUI (idade média 45.0 ± 10.5 anos) e 15 pacientes saudáveis (idade média 42.1 ± 7.8 anos) participaram desse estudo. Todos os dentes presentes, com exceção dos terceiros molares, foram examinados. Profundidade de bolsa (PB), nível de inserção clínica (NI), presença de placa e de sangramento a sondagem foram avaliados em seis sítios por dente. Em cada paciente, o fluido de 4 sítios com periodontite (PB ≥ 5 mm e NI ≥ 3mm) e de 4 sítios com gengivite (PB ≤ 3 mm e NI ≤ 1 mm) foram coletados através de pontas de papel absorvente pré-fabricadas. O sistema LUMINEX® foi utilizado na mensuração das IL-1β, IL-4, IL-6, IL-10, IL-12p70, TNFα, INFγ, MMP-8 e MMP-9. A IL-18 foi analisada através do ensaio ELISA e a atividade de elastase através de uma reação enzimática. O soro desses pacientes também foi analisado e o coeficiente de correlação de Pearson foi utilizado na análise da correlação entre as citocinas no soro e no fluido gengival. Nos sítios com gengivite, a quantidade total de IL-4 foi significativamente menor no grupo RCUI do que no grupo GC (p=0.016). Nos sítios com periodontite, a quantidade total de IL-4 foi significativamente menor no grupo DC do que no grupo GC (p=0.029)...

The aim of this thesis was to evaluate the expression of Th1 cytokines (IL-12 and INF-γ), Th2 cytokines (IL-4, IL-6 and IL-10) and the pro-inflammatory cytokines IL-18, IL-1β and TNF-α in the gingival crevicular fluid (GCF) from Crohn’s disease (CD) patients, ulcerative colitis (UC) patients and healthy individuals (control group, CG) who had chronic periodontitis. Besides, we measured elastase activity, matrix metalloproteinase -8 and -9 (MMP-8 and -9) to address the neutrophil function in the GCF. Fifteen CD patients (mean age 38.2 ± 11.4 years), 15 UC patients (mean age 45.0 ± 10.5 years) and 15 systemically healthy controls (mean age 42.1 ± 7.8 years) were enrolled in this study. All the present teeth, except for the third molars were examined. Probing pocket depth (PPD), clinical attachment loss (CAL), presence of plaque and presence of bleeding on probing were assessed in six sites per tooth. In every subject, GCF from 4 gingivitis sites (PPD ≤ 3mm and CAL ≤ 1mm) and from 4 periodontitis sites (PPD ≥ 5mm and CAL ≥ 3mm) were collected with filter strips. The data were reported as total amount and concentration. IL-1β, IL-4, IL-6, IL-10, IL-12p70, TNFα, INFγ, MMP-8 and MMP-9 were analyzed by the Luminex® analyzer. IL-18 was analyzed using a commercially available ELISA assay and the elastase activity by an enzymatic reaction. The serum was also analysed and the correlations between the cytokines in the GCF and in the serum were calculated by Pearson correlation analysis. In gingivitis sites, the total amount of IL-4 was significantly lower in the UC group than in the CG group (p=0.016). In periodontitis sites, the total amount of IL-4 was significantly lower in CD group than in the CG group (p=0.029). The total amount of IL-4 was lower in UC group than in CD group (p=0.077)...

Photochemistry and photobiology of actinic erythema: defensive and reparative cutaneous mechanisms

Sunlight is part of our everyday life and most people accept it as beneficial to our health. With the advance of our knowledge in cutaneous photochemistry, photobiology and photomedicine over the past four decades, the terrestrial solar radiation has become a concern of dermatologists and is considered to be a major damaging environmental factor for our skin. Most photobiological effects (e.g., sunburn, suntanning, local and systemic immunosuppression, photoaging or dermatoheliosis, skin cancer and precancer, etc.) are attributed to ultraviolet radiation (UVR) and more particularly to UVB radiation (290-320 nm). UVA radiation (320-400 nm) also plays an important role in the induction of erythema by the photosensitized generation of reactive oxygen species (singlet oxygen ((1)O2))superoxide (O2-) and hydroxyl radicals ((OH) that damage DNA and cellular membranes, and promote carcinogenesis and the changes associated with photoaging. Therefore, research efforts have been directed at a better photochemical and photobiological understanding of the so-called sunburn reaction, actinic or solar erythema. To survive the insults of actinic damage, the skin appears to have different intrinsic defensive mechanisms, among which antioxidants (enzymatic and non-enzymatic systems) play a pivotal role. In this paper, we will review the basic aspects of the action of UVR on the skin: a) photochemical reactions resulting from photon absorption by endogenous chromophores; b) the lipid peroxidation phenomenon, and c) intrinsic defensive cutaneous mechanisms (antioxidant systems). The last section will cover the inflammatory response including mediator release after cutaneous UVR exposure and adhesion molecule expression.

Mecanismos moleculares da rejeiçäo dos transplantes de órgäos vascularizados / Molecular mechanisms of transplant rejection of vascularized organs

O completo entendimento dos fatores que determinam o sucesso ou a rejeição de um órgão transplantado (enxerto) requer o conhecimento de suas estruturas antigênicas, dos mecanismos de reconhecimento do antígeno, das diferentes populações celulares e da produção das citoninas pelo sistema imunológico do receptor, bem como dos eventos bioquímicos e moleculares que ocorrem no processo de rejeição dos transplantes. Neste capítulo será dado ênfase para os recentes progressos obtidos na compreensão das bases moleculares dos mecanismos de rejeição dos transplantes, pois esse conhecimento pode ser de fundamental importância para a elaboração de novos protocolos de imunossupressão e para o entendimento do mecanismo de ação de novas drogas imunossupressivas.

Simposio: cirugía experimental en México (parte I): producción in vivo e in vitro de óxido nítrico por hepatocitos / Symposium: experimental surgery in Mexico (part l): in vivo and in vitro production of nitric oxide by hepatocytes

Objetivo: Demostrar que el óxido nítrico producido por el hígado juega un papel protector en este órgano durante episodios de sepsis. Diseño: Estudio experimental en animales, prospectivo con grupo control. Material y métodos: Se utilizaron ratas Sprague-Dawley machos con peso entre 200 y 250 g. Para experimento in vivo, los animales recibieron una sola inyección de 28 mg/kg/IV de Corynebacterium parvum; ratas normales se emplearon como controles y donadores de hepatocitos para los estudios in vitro. Los hepatocitos normales y estimulados con C. parvum fueron aislados utilizando una modificación a la técnica de perfusión de colagenasa in situ; fueron colocados en platos de Petri con una capa de gelatina de 100 mm en 6 ml de medio de cultivo que contenía: L-arginina, insulina, L-glutaminam, penicilina, streptomicina y 10 por ciento de suero bajo en endotoxina. Después e 24 h en cultivo los hepatocitos recibieron medio frasco adicionado de citoquinas (INF+TNF+IL-1) y endotoxina (LPS para estimular la producción de óxido nítrico in vitro. Los sobrenadantes fueron colectados, almacenados y sujetos a medición de NO2 + NO3 empleando un método automático colorimétrico