Comparison of immunoglobulins of normal animals and animals infected and immunized with Trypanosoma brucei

The immunoglobulins of normal rabbits and mice, and rabbits and mice infected and immunized with T. brace! have been compared. The methods used in the study included the biuret test for total protein estimation, zinc sulphate test for gamma-globulin determination and gel diffusion techniques for determining serum immunoglobulin levels. The proportions of the different serum protein fractions here obtained by electrophoresis while characterization of the immunoglobulins was done by gel chromatography and agglutination tests. In infected rabbits, the total protein content increased during the infection and there was a decrease in the proportion of albumin while the gamma-global ins increased both in proportion and absolute concentration. The serum IgG titre increased slightly, "but the titre increased markedly to more than 32 times the preinfection level within 3 weeks. The agglutinin titre of the sera rose to a peak at 3 weeks but started to decline by the fifth week. Agglutinin activity was found in the IgM fraction alone, up to 3 weeks after infection but thereafter it occurred in both IgG and IgM fractions. Attempts to immunize rabbits by infection and drug-treatment were unsuccessful and no changes occurred in the sera of test and control animals. In mice, homologous challenge with the infecting strain of T. brucei showed that the immunization procedure was more successful and also demonstrated the protective effect of antibody. The changes in the total serum protein contents were not marked but the relative proportion of albumin in the sera of immunized mice decreased after immunization, while both the beta- and gamma-globulins increased in proportion and absolute amounts. High agglutinin titres appeared within a week and reached a peak at 3 weeks. Agglutinin activity occurred in the IgM fraction only soon after immunization but by the fourth week, both IgG and IgM fractions contained agglutinating antibodies

Microcharacterization of Fluid Inclusions in Minerals by Raman Microprobe

Fluids trapped in inclusions in minerals are micro-amounts of ore-forming media composed of water, dissolved salts, gases and sometimes liquefied gases, liquid, hydrocarbons and solids. The aim of this paper is to summarize the contribution of the Raman scattering microspectrometry to the knowledge of fluid inclusions. After a review of the composition of fluid inclusions and a short presentation of microthermometrical investigations, a description of the Raman microprobe is given. Applications are reviewed; identification of ionic species dissolved in aqueous phase, characterization of gases of C-O-H-N-S system, identification of solids and non aqueous liquids. The complementary characteristics of Raman microanalysis and microthermometry are underlined. The last section is devoted to comparisons with other microprobes from the point of view of chemical and mineralogical analysis of fluid inclusions

Scheelite bearing quartz veins from Poblet (Catalonian Coastal Ranges): Characterisation of fluid inclussions and genetic model

Scheelite-bearing quartz veins from Poblet, trending in a NE-SW direction, are hosted by calcic granitoids of Late Hercynian age in the southern part of the Catalonian Coast Range. Fluid inclusions from quartz and scheelite have been characterized using microthermometry, Raman microspectrometry and Scanning Electron Microscopy. Except for type I inclusions (not observed in scheelite), similar inclusions have been observed in both minerals. One recognizes, in order of formation : Type I inclusions containing brine, daughter phases (halite, sylvite and sometimes iron chloride) and incidentally trapped minerals (ankerite, siderite, muscovite, K-felspar and unidentified species). Type II(L) inclusions have a low salinity (1 to 6 % eq. NaCl) and homogenize in the liquid phase in the range of 300-400 °C or under critical conditions near 400 °C. Type II(V) are low density, CO2-poor aqueous inclusions, homogenizing in the gas phase in the range of 350-420 °C. Type II(V') have higher CO2 contents. Type II inclusions appear as samples of an initially hypercritical fluid, trapped at different stages of its evolutions towards two subcritical fluids. Type III inclusions indicate later circulation of a colder, low-salinity solution (Th : 150 to 300 °C ; salinity : 0 to 3.5 % NaCl wt %). Abundant iron contents in type I inclusions suggest some interaction at elevated temperature (400 to 600°C) with a biotite granite (Whitney et al., 1985). P-T conditions compatible with measurements performed on type II inclusions are about 400 °C and 0.8 kbar, in a range similar to that determined for the Djbel Aouam occurrence in Hercynian Morocco (Cheilletz, 1984). Equivalent conditions have been postulated for scheelite precipitation at Poblet

Monitoring the introduction of pneumococcal conjugate vaccines into West Africa: design and implementation of a population-based surveillance system.

Routine use of pneumococcal conjugate vaccines (PCVs) in developing countries is expected to lead to a significant reduction in childhood deaths. However, PCVs have been associated with replacement disease with non-vaccine serotypes. We established a population-based surveillance system to document the direct and indirect impact of PCVs on the incidence of invasive pneumococcal disease (IPD) and radiological pneumonia in those aged 2 months and older in The Gambia, and to monitor changes in serotype-specific IPD. Here we describe how this surveillance system was set up and is being operated as a partnership between the Medical Research Council Unit and the Gambian Government. This surveillance system is expected to provide crucial information for immunisation policy and serves as a potential model for those introducing routine PCV vaccination in diverse settings

Maintenance of Large Subpopulations of Differentiated CD8 T-Cells Two Years after Cytomegalovirus Infection in Gambian Infants

BACKGROUND: In a previously published study, we found that large differentiated subpopulations of CD8 T-cells emerged rapidly after CMV infection in young infants and persisted throughout the following year. Here we describe a follow-up study conducted on the same infants to establish whether the differentiated subpopulations continued through the second year post-infection. METHODOLOGY / PRINCIPAL FINDINGS: CMV-specific cells identified using tetramers remained more activated and differentiated than the overall CD8 population. The large subpopulation of differentiated cytotoxic (CD28(-)CD62L(-)Bcl-2(low)CD95(+)perforin(+)) cells that emerged rapidly after infection remained stable after two years. No similar subpopulation was found in CMV-uninfected infants indicating that two years after infection, CMV remained a major factor in driving CD8 T-cell differentiation. Although markers of activation (CD45R0 and HLA-D) declined throughout the first year, HLA-D expression continued to decline during the second year and CD45R0 expression increased slightly. The age-related increase in IFNgamma response observed during the first year continued but was non-significant during the second year, indicating that the rate of functional improvement had slowed substantially. CONCLUSIONS / SIGNIFICANCE: The large differentiated subpopulations of CD8 T-cells that had emerged immediately after CMV infection persisted through the second year post-infection, while levels of activation and functional capacity remained fairly constant.Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Age-Dependent Maturation of Toll-Like Receptor-Mediated Cytokine Responses in Gambian Infants

The global burden of neonatal and infant mortality due to infection is staggering, particularly in resource-poor settings. Early childhood vaccination is one of the major interventions that can reduce this burden, but there are specific limitations to inducing effective immunity in early life, including impaired neonatal leukocyte production of Th1-polarizing cytokines to many stimuli. Characterizing the ontogeny of Toll-like receptor (TLR)-mediated innate immune responses in infants may shed light on susceptibility to infection in this vulnerable age group, and provide insights into TLR agonists as candidate adjuvants for improved neonatal vaccines. As little is known about the leukocyte responses of infants in resource-poor settings, we characterized production of Th1-, Th2-, and anti-inflammatory- cytokines in response to agonists of TLRs 1-9 in whole blood from 120 Gambian infants ranging from newborns (cord blood) to 12 months of age. Most of the TLR agonists induced TNFα, IL-1β, IL-6, and IL-10 in cord blood. The greatest TNFα responses were observed for TLR4, -5, and -8 agonists, the highest being the thiazoloquinoline CLO75 (TLR7/8) that also uniquely induced cord blood IFNγ production. For most agonists, TLR-mediated TNFα and IFNγ responses increased from birth to 1 month of age. TLR8 agonists also induced the greatest production of the Th1-polarizing cytokines TNFα and IFNγ throughout the first year of life, although the relative responses to the single TLR8 agonist and the combined TLR7/8 agonist changed with age. In contrast, IL-1β, IL-6, and IL-10 responses to most agonists were robust at birth and remained stable through 12 months of age. These observations provide fresh insights into the ontogeny of innate immunity in African children, and may inform development of age-specific adjuvanted vaccine formulations important for global health

Plasmodium Protease ROM1 Is Important for Proper Formation of the Parasitophorous Vacuole

Apicomplexans are obligate intracellular parasites that invade host cells by an active process leading to the formation of a non-fusogenic parasitophorous vacuole (PV) where the parasite replicates within the host cell. The rhomboid family of proteases cleaves substrates within their transmembrane domains and has been implicated in the invasion process. Although its exact function is unknown, Plasmodium ROM1 is hypothesized to play a role during invasion based on its microneme localization and its ability to cleave essential invasion adhesins. Using the rodent malaria model, Plasmodium yoelii, we carried out detailed quantitative analysis of pyrom1 deficient parasites during the Plasmodium lifecycle. Pyrom1(-) parasites are attenuated during erythrocytic and hepatic stages but progress normally through the mosquito vector with normal counts of oocyst and salivary gland sporozoites. Pyrom1 steady state mRNA levels are upregulated 20-fold in salivary gland sporozoites compared to blood stages. We show that pyrom1(-) sporozoites are capable of gliding motility and traversing host cells normally. Wildtype and pyrom1(-) sporozoites do not differ in the rate of entry into Hepa1–6 hepatocytes. Within the first twelve hours of hepatic development, however, only 50% pyrom1(-) parasites have developed into exoerythrocytic forms. Immunofluorescence microscopy using the PVM marker UIS4 and transmission electron microscopy reveal that the PV of a significant fraction of pyrom1(-) parasites are morphologically aberrant shortly after invasion. We propose a novel function for PyROM1 as a protease that promotes proper PV modification to allow parasite development and replication in a suitable environment within the mammalian host