Migration and localization of NK cells into peripheral tissues are tightly regulated under normal and pathological conditions. The physiological importance of NK cell-DC crosstalk has been well documented. However, the ways in which DCs regulate the migratory properties of NK cells (such as chemotaxis, chemokinesis, chemo-repulsion) are not fully defined in vitro. Here, we employed a microfluidic platform to examine, at the single-cell level, C57BL/6 NK-cell migrations in a stable chemical gradient. We observed that soluble factors released by the immature and LPS-activated mature DCs induced a high level of chemotactic movement of IL-2-activated NK cells in vitro. We confirmed these findings in a standard trans-well migration assay, and identified CXCR3 as a key receptor on the NK cells that mediated the migration. More interestingly, we revealed a novel function of granulocyte macrophage colony-stimulating factor in repulsing NK-cell migrations. The future uses of such microfluidic device in the systematic evaluations of NK-cell migratory responses in NK cell-DC crosstalk will provide new insights into the development of DC-based NK-cell therapies against tumor and infections.Keywords: Bone marrow-derived dendritic cells r Chemo-repulsion r Chemotaxis r Microfluidic device r Natural killer cell r NK-DC crosstalk Additional supporting information may be found in the online version of this article at the publisher's web-site Introduction NK cells are motile bone marrow (BM)-derived lymphocytes that play a key role in innate immunity against viral, microbial infections, and transformed cells [1][2][3]. They are capable of killing transformed or infected cells [1,2,4,5], and/or producing cytokines/chemokines that can profoundly influence the quality and magnitude of the adaptive immune responses [6][7][8][9]. They Correspondence: Dr. Sam K. P. Kung e-mail: Sam.Kung2@med.umanitoba.ca acquire specific chemokine surface receptors during development and maturation [2,[10][11][12][13][14][15]. Chemokine receptors such as CCR7, CCR5, and CXCR3 are involved in the preferential migrations and localization of NK cells into the LNs [8,[16][17][18][19], whereas NK cells reside in blood, liver, and spleen exhibit higher CXCR1 and CX 3 CR1 expression [8,9,[20][21][22][23][24][25]. Nonchemokine family proteins such as chemerin and SIP 5 are also involved in the regulation of NK-cell trafficking [26,27]. Collectively, they highlight the complexity of the environmental regulation of NK-cell migrations in physiological and pathological conditions. NK-cell activation and functions are regulated by cytokine/ chemokine and/or DC in the microenvironments [18,[28][29][30] [36,37]. In this report, we demonstrated an application of such microfluidic device in examining how soluble factors produced by DC regulated NK-cell migrations in vitro. Results A microfluidic platform to perform live-cell imaging of NK-cell migrationsWe used the established Y-shaped microfluidic device to examine chemotactic or chemo-repulsive movements of NK cells ...
Summary African swine fever (ASF) has been endemic in sub‐Saharan Africa since the 1960s. Following its introduction in Senegal, in 1957, ASF steadily progressed through West Africa, reaching Burkina Faso in 2003, and later Mali in 2016. Despite the heavy burden of disease on pig production, little information is available on the genetic diversity of Africa swine fever virus (ASFV) in Burkina Faso, Mali and Senegal. Here, we used real‐time PCR ASFV to detect the ASFV genome in samples collected between 1989 and 2016, in Burkina Faso, Mali and Senegal, and conventional approaches for isolate characterization. The C‐terminal end of the p72 protein gene, the full E183L gene and the central variable region (CVR) within the B602L gene in ASFV genome were sequenced and compared to publicly available sequences. ASFV genome was found in 27 samples, 19 from Burkina Faso, three from Mali and five from Senegal. The phylogenetic analyses showed that all viruses belong to genotype I, with the ASFVs from Burkina Faso and Mali grouping with genotype Ia and ASFV serogroup 4, and those from Senegal with genotype Ib and the ASFV serogroup 1. The analysis of the CVR tetrameric tandem repeat sequences (TRS) showed four TRS variants in Burkina Faso, two in Senegal and one in Mali. The three countries did not share any common TRS, and all CVRs of this study differed from previously reported CVRs in West Africa, except for Senegal. Three of the five isolates from Senegal fully matched with the CVR, p72 and p54 sequences from ASFV IC96 collected during the 1996 ASF outbreak in Ivory Coast. This study shows the spread of the same ASFV strains across countries, highlighting the importance of continuous monitoring of ASFV isolates. It also calls for an urgent need to establish a regional plan for the control and eradication of ASF in West Africa.
NK cells and dendritic cells (DC) are innate cellular components that regulate adaptive immune responses in the immune surveillance of cancer and infections. Interactions of NK and DC are bidirectional. In this mini review, we summarized how NK cells regulate immature DC editing and maturation, how DC regulate NK-cell functions reciprocally in the NK-DC crosstalk, and the importance of NK-DC crosstalk in antitumor immunity. Enhancing NK-DC crosstalk by cellular factor(s), antibodies or creating a microenvironment that promote NK activations, DC maturation and NK-DC crosstalk will provide new insights into future development of DC-based immunotherapy.
In Mali, poultry farming is a valuable source of income for the population. With huge production potential, the conditions necessary to achieve the quality and safety of poultry products must be in place. This study, conducted between February 2017and May2018 had the objective of assessing the bacteriological prevalence of salmonella in eggs and poultry carcasses slaughtered in the district of Bamako. It focused on analyzing carcasses384 and112 eggs collected from poultry at markets and slaughterhouses. The individual samples were first sown on medium preenrichment and on enrichment media followed by isolation of the bacteria on selective media and identification by biochemical tests. Work has established a global prevalence of bacteriological 12, 90%which varied depending on the type of poultry forhens14.91% against10.88%guinea fowl, the nature of the sample (eggs (09, 82%) and carcasses (13.80%) and the sampling site (the more was observed at Niamakoro monitoring Boulkassoumbougou and Hamdallaye).
Canine rabies remains an important public health problem in Africa. Mass vaccination of dogs is the recommended method for the control and elimination of rabies. We report the second free mass vaccination campaign of the dog in the communes V and VI of the district of Bamako that took place in September 2014. The objective was to estimate vaccination coverage by evaluating the effectiveness of the vaccination campaign and to determine the effectiveness parameters of the intervention by the capture mark recapture method and the Bayesian model. In commune V, vaccination coverage was 27% with a canine population estimated at 1531 and the proportion of dogs without owners was 2%. For commune VI, the canine population was estimated at 3510 with a vaccination coverage of 20%. The proportion of the nonowner dog population was 8%. The final effectiveness was 33% and 28% respectively in communes V and VI. Availability has been identified as the most sensitive effectiveness parameter attributed to the lack of campaign information. Despite low immunization coverage, it is possible to carry out vaccination campaigns that had an impact in Bamako district. For higher immunization coverage, a vaccination strategy adapted locally, perhaps, through a combination of fixed-line immunization and door-to-door vaccination.
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