The effect of carbohydrate depletion on procoagulant activity and in vivo survival of highly purified human factor VIII

Human factor VIII procoagulant protein (factor VIII) was purified using a modification of our previously described method, in which Sephacryl S-400 elution, rather than QAE-cellulose chromatography, served as the final purification step. The protein had a specific activity of more than 2500 U/mg and consisted of a single polypeptide (Mr 100 000) when analyzed by SDS-polyacrylamide gel electrophoresis. Factor VIII was shown to be a glycoprotein by staining with periodic acid-Schiff's reagent following electrophoresis. Treatment of factor VIII with a mixture of exo- and endoglycosidases caused a reduction by about 50% in the intensity of periodic acid-Schiff staining, as determined by scanning densitometry, and an increase in electrophoretic mobility (equivalent to a new Mr 95 000). Removal of this portion of the total carbohydrate had no significant effect on factor VIII clotting activity or on thrombin potentiation of clotting activity. The in vivo survival curves of a native and sugar-depleted 125I-labeled factor VIII both showed similar patterns of initial rapid decay to 60 and 40% activity, respectively, followed by a one-half decay time of 4 h for both. These results suggest that the carbohydrate portion of human factor VIII does not contribute significantly to either clotting function in vitro or to biological turnover in vivo.     

A review of malaria vaccine clinical projects based on the WHO rainbow table

Development and Phase 3 testing of the most advanced malaria vaccine, RTS,S/AS01, indicates that malaria vaccine R&D is moving into a new phase. Field trials of several research malaria vaccines have also confirmed that it is possible to impact the host-parasite relationship through vaccine-induced immune responses to multiple antigenic targets using different platforms. Other approaches have been appropriately tested but turned out to be disappointing after clinical evaluation. As the malaria community considers the potential role of a first-generation malaria vaccine in malaria control efforts, it is an apposite time to carefully document terminated and ongoing malaria vaccine research projects so that lessons learned can be applied to increase the chances of success for second-generation malaria vaccines over the next 10 years. The most comprehensive resource of malaria vaccine projects is a spreadsheet compiled by WHO thanks to the input from funding agencies, sponsors and investigators worldwide. This spreadsheet, available from WHO's website, is known as "the rainbow table". By summarizing the published and some unpublished information available for each project on the rainbow table, the most comprehensive review of malaria vaccine projects to be published in the last several years is provided below.     

Composition and stability of the vervet monkey milk microbiome

The human milk microbiome is vertically transmitted to offspring during the postnatal period and has emerged as a critical driver of infant immune and metabolic development. Despite this importance in humans, the milk microbiome of nonhuman primates remains largely unexplored. This dearth of comparative work precludes our ability to understand how species‐specific differences in the milk microbiome may differentially drive maternal effects and limits how translational models can be used to understand the role of vertically transmitted milk microbes in human development. Here, we present the first culture‐independent data on the milk microbiome of a nonhuman primate. We collected milk and matched fecal microbiome samples at early and late lactation from a cohort of captive lactating vervet monkeys (N = 15). We found that, similar to humans, the vervet monkey milk microbiome comprises a shared community of taxa that are universally present across individuals. However, unlike in humans, this shared community is dominated by the genera Lactobacillus, Bacteroides, and Prevotella. We also found that, in contrast to previous culture‐dependent studies in humans, the vervet milk microbiome exhibits greater alpha‐diversity than the gut microbiome across lactation. Finally, we did not find support for the translocation of microbes from the gut to the mammary gland within females (i.e., “entero‐mammary pathway”). Taken together, our results show that the vervet monkey milk microbiome is taxonomically diverse, distinct from the gut microbiome, and largely stable. These findings demonstrate that the milk microbiome is a unique substrate that may selectively favor the establishment and persistence of particular microbes across lactation and highlights the need for future experimental studies on the origin of microbes in milk.