Evaluation of Toll-like, chemokine, and integrin receptors on monocytes and neutrophils from peripheral blood of septic patients and their correlation with clinical outcomes

Recognition of pathogens is performed by specific receptors in cells of the innate immune system, which may undergo modulation during the continuum of clinical manifestations of sepsis. Monocytes and neutrophils play a key role in host defense by sensing and destroying microorganisms. This study aimed to evaluate the expression of CD14 receptors on monocytes; CD66b and CXCR2 receptors on neutrophils; and TLR2, TLR4, TLR5, TLR9, and CD11b receptors on both cell types of septic patients. Seventy-seven septic patients (SP) and 40 healthy volunteers (HV) were included in the study, and blood samples were collected on day zero (D0) and after 7 days of therapy (D7). Evaluation of the cellular receptors was carried out by flow cytometry. Expression of CD14 on monocytes and of CD11b and CXCR2 on neutrophils from SP was lower than that from HV. Conversely, expression of TLR5 on monocytes and neutrophils was higher in SP compared with HV. Expression of TLR2 on the surface of neutrophils and that of TLR5 on monocytes and neutrophils of SP was lower at D7 than at D0. In addition, SP who survived showed reduced expression of TLR2 and TLR4 on the surface of neutrophils at D7 compared to D0. Expression of CXCR2 for surviving patients was higher at follow-up compared to baseline. We conclude that expression of recognition and cell signaling receptors is differentially regulated between SP and HV depending on the receptor being evaluated.

Programmed cell death of B lymphocytes is induced by ligation of integrin-associated protein [CD47]

As part of the Immunoglobulin [Ig] superfamily, the transmembrane glycoprotein CD47 forms a signalling complex with the CD23 receptor alphavbeta3 integrin, which stimulates cytokine synthesis and controls inflammation by regulating leukocyte activation and the phagocytosis of aging apoptotic leukocytes. To investigate the effects of anti-CD47 antibodies on a range of cell types at varying stages of development. Using flow cytometric analysis, KMS11 and H929 human B lymphocyte multiple myeloma cell lines were used to study the expression of CD47 and alphavbeta3 integrin as a means to explore the factors relating to the induction and resistance to apoptosis. We found that both cell lines expressed high levels of CD47, with KMS11 cells expressing more than H929 cells. CD47 stimulated an increase in apoptosis in both KMS11 and H929 cells with the preponderance being late apoptotic, dying cells. Ligation of CD47 via the soluble phase was crucial for apoptosis to take place. These results provided an insight into the apoptotic mechanisms involved in the control of inflammation surrounding the activation and phagocytosis of leukocytes. In conclusion, further analysis is required to elucidate the complete signaling cascade responsible for this proliferative effect. Induction of apoptosis via CD47 stimulation appears to occur in the absence of CD47's signaling complex partner, alphavbeta3 whether or not apoptosis occurs, appears to be dependent upon the cell type and also the way CD47 is engaged

Organizaçäo do citoesqueleto e distribuiçäo da integrina 'ALFA' Ýb ß3 em plaquetas estimuladas por trombina: aplicaçöes no estudo de pacientes portadores de hipertensäo arterial pulmonar / Organization of cytoskeleton and distribution of integrin 'ALFA' Ýb ß3 in the study of pulmonary hypertensive patients

Os mecanismos envolvidos na ativaçäo e agregaçäo plaquetária em condiçöes fisiológicas e patológicas, têm sido amplamente investigados. O propósito deste estudo foi: 1. Estabelecer alguns métodos para análise da organizaçäo de elementos contráteis e distribuiçäo da integrina 'ALFA' Ýb ß3 em plaquetas normais estimuladas por trombina. Os experimentos foram realizados utilizando-se lisado total e preparaçöes de citoesqueleto e membrana plaquetária. Em todos os ensaios, a integrina foi identificada por "Western immunoblotting" com anticorpo anti-cadeia ß3; 2. O mesmo protocolo foi empregado para analisar os resultados em pacientes portadores de hipertensäo pulmonar, nas quais ativaçäo e agregaçäo de plaquetas ocorrem in vivo como já demonstrado; 3. Finalmente, os efeitos do ácido acetilsalicílico na organizaçäo do citoesqueleto e na retençäo da integrina 'ALFA' Ýb ß3 foram estudados em plaquetas normais utilizando-se a mesma metodologia...