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There has been a recent move toward active learning pedagogies in veterinary education, with increasing use of a blended approach that incorporates both online resources and live classroom sessions. In this study, an established veterinary pre-clinical course in introductory animal health was transitioned from a traditional didactic lecture delivery mode to a flipped classroom approach with core content delivered online. This study compared the experiences of two cohorts of students who studied the same course in the different formats in consecutive years. Online learning resources included short video segments and a variety of short problems and activities. Online materials were complemented with weekly small-group case-based learning classes facilitated by academic staff. A mixed methods evaluation strategy was applied using student grades, surveys, and focus groups to compare student academic performance, satisfaction, and engagement between the two cohorts. The flipped classroom cohort achieved significantly higher grades in the written answer section of the final examination. Student satisfaction with learning resources was also higher in this cohort. However, satisfaction with other aspects of the course was largely the same for both cohorts. This study revealed some of the challenges associated with achieving adequate student preparation for class using online resources. The outcomes of this study have implications for veterinary educators considering the design and development of new online learning resources.

Rrd1p (resistance to rapamycin deletion 1) has been previously implicated in controlling transcription of rapamycin-regulated genes in response to rapamycin treatment. Intriguingly, we show here that Rrd1p associates with the coding sequence of a galactose-inducible and rapamycin non-responsive GAL1 gene, and promotes the association of RNA polymerase II with GAL1 in the absence of rapamycin treatment following transcriptional induction. Consistently, nucleosomal disassembly at GAL1 is impaired in the absence of Rrd1p, and GAL1 transcription is reduced in the Δrrd1 strain. Likewise, Rrd1p associates with the coding sequences of other rapamycin non-responsive and inducible GAL genes to promote their transcription in the absence of rapamycin treatment. Similarly, inducible, but rapamycin-responsive, non-GAL genes such as CTT1, STL1 and CUP1 are also regulated by Rrd1p. However, transcription of these inducible GAL and non-GAL genes is not altered in the absence of Rrd1p when the steady-state is reached after long transcriptional induction. Consistently, transcription of the constitutively active genes is not changed in the Δrrd1 strain. Taken together, our results demonstrate a new function of Rrd1p in stimulation of initial rounds of transcription, but not steady-state/constitutive transcription, of both rapamycin-responsive and non-responsive genes independently of rapamycin treatment.

The particular virulence of the human malaria parasite Plasmodium falciparum derives from export of parasite-encoded proteins to the surface of the mature erythrocytes in which it resides. The mechanisms and machinery for the export of proteins to the erythrocyte membrane are largely unknown. In other eukaryotic cells, cholesterol-rich membrane microdomains or “rafts” have been shown to play an important role in the export of proteins to the cell surface. Our data suggest that depletion of cholesterol from the erythrocyte membrane with methyl-β-cyclodextrin significantly inhibits the delivery of the major virulence factor P. falciparum erythrocyte membrane protein 1 (PfEMP1). The trafficking defect appears to lie at the level of transfer of PfEMP1 from parasite-derived membranous structures within the infected erythrocyte cytoplasm, known as the Maurer's clefts, to the erythrocyte membrane. Thus our data suggest that delivery of this key cytoadherence-mediating protein to the host erythrocyte membrane involves insertion of PfEMP1 at cholesterol-rich microdomains. GTP-dependent vesicle budding and fusion events are also involved in many trafficking processes. To determine whether GTP-dependent events are involved in PfEMP1 trafficking, we have incorporated non-membrane-permeating GTP analogs inside resealed erythrocytes. Although these nonhydrolyzable GTP analogs reduced erythrocyte invasion efficiency and partially retarded growth of the intracellular parasite, they appeared to have little direct effect on PfEMP1 trafficking.

The 26S proteasome complex engages in an ATP-dependent proteolytic degradation of a variety of oncoproteins, transcription factors, cell cycle specific cyclins, cyclin-dependent kinase inhibitors, ornithine decarboxylase, and other key regulatory cellular proteins. Thus, the proteasome regulates either directly or indirectly many important cellular processes. Altered regulation of these cellular events is linked to the development of cancer. Therefore, the proteasome has become an attractive target for the treatment of numerous cancers. Several proteasome inhibitors that target the proteolytic active sites of the 26S proteasome complex have been developed and tested for anti-tumor activities. These proteasome inhibitors have displayed impressive anti-tumor functions by inducing apoptosis in different tumor types. Further, the proteasome inhibitors have been shown to induce cell cycle arrest, and inhibit angiogenesis, cell-cell adhesion, cell migration, immune and inflammatory responses, and DNA repair response. A number of proteasome inhibitors are now in clinical trials to treat multiple myeloma and solid tumors. Many other proteasome inhibitors with different efficiencies are being developed and tested for anti-tumor activities. Several proteasome inhibitors currently in clinical trials have shown significantly improved anti-tumor activities when combined with other drugs such as histone deacetylase (HDAC) inhibitors, Akt (protein kinase B) inhibitors, DNA damaging agents, Hsp90 (heat shock protein 90) inhibitors, and lenalidomide. The proteasome inhibitor bortezomib is now in the clinic to treat multiple myeloma and mantle cell lymphoma. Here, we discuss the 26S proteasome complex in carcinogenesis and different proteasome inhibitors with their potential therapeutic applications in treatment of numerous cancers.

Limited data are available on the kinetics of meningococcal serogroup C (MenC)-specific antibody responses following parenteral or nasal challenge in those who have received prior MenC vaccination (polysaccharide or conjugate). Young adults who had previously received either meningococcal A/C polysaccharide (MACP) or MenC conjugate (MCC) vaccine or naïve subjects were challenged with MACP via one of two routes, nasal or parenteral. Blood samples were taken prevaccination and on days 1 to 4 and day 10 postvaccination. MenC serum bactericidal antibody (SBA) and MenC-specific IgG were measured. Following parenteral challenge, MenC SBA and IgG responses were seen to occur between 4 and 7 days postchallenge. A lower proportion of subjects responded following nasal challenge, with naïve subjects showing little change in SBA geometric mean titer (GMT) and IgG geometric mean concentration (GMC) over the 10 days following challenge. Increases in SBA GMTs were seen between 4 and 7 days after nasal challenge in those who had received prior MCC and between 7 and 10 days in those who had received prior MACP, and the responses in the prior-MACP group were of lower magnitude than the responses of the prior-MCC group. The data presented here indicate that, following MCC vaccination, memory has been induced at the mucosal level, and these subjects were able to respond with increases in SBA levels. These results demonstrate that the speed of response (primary or secondary) to challenge with MenC polysaccharide via the nasal or parenteral route does not differ and support concerns that immunological memory alone is too slow to provide protection.

The United Kingdom introduced meningococcal serogroup C conjugate (MCC) vaccines in 1999, resulting in substantial declines in serogroup C disease and carriage. Here, we measured the age-specific prevalence of serum bactericidal antibodies (SBA) to Neisseria meningitidis serogroup C and immunoglobulin G (IgG) concentrations to serogroups A, C, W-135, and Y in 2,673 serum samples collected in England between 2000 and 2004. We compared the seroprevalence of SBA titers of ≥8 in the postvaccination era with results from an earlier prevaccination study conducted using the same methods. We found that the percentages of individuals with protective SBA titers were higher in 2000 to 2004 in all of the age groups targeted for MCC vaccination. In the postvaccine era, the prevalence of protective titers was high (75%) in children who had recently been offered routine immunization, but this fell to 36% more than 18 months after scheduled immunization. In the cohorts targeted in the catch-up campaign, the percentage achieving SBA titers of ≥8 was higher in children offered the vaccine at ages 5 to 17 years than in children offered the vaccine at ages 1 to 4 years. The geometric mean concentration (GMC) IgG for serogroup C followed a similar pattern, corresponding to the age at and time since scheduled MCC vaccination. Serogroup-specific IgG GMCs for W-135 and Y were low and showed little variation by age. Serogroup A IgG GMCs were higher, possibly reflecting exposure to cross-reacting antigens. Although the incidence of serogroup C disease remains low due to persisting herd effects, population antibody levels to serogroup C meningococci should be monitored so that potentially susceptible age groups can be identified should herd immunity wane.

During intraerythrocytic development, the human malaria parasite, Plasmodium falciparum, establishes membrane-bound compartments, known as Maurer's clefts, outside the confines of its own plasma membrane. The Maurer's compartments are thought to be a crucial component of the machinery for protein sorting and trafficking; however, their ultrastructure is only partly defined. We have used electron tomography to image Maurer's clefts of 3D7 strain parasites. The compartments are revealed as flattened structures with a translucent lumen and a more electron-dense coat. They display a complex and convoluted morphology, and some regions are modified with surface nodules, each with a circular cross-section of approximately 25 nm. Individual 25 nm vesicle-like structures are also seen in the erythrocyte cytoplasm and associated with the red blood cell membrane. The Maurer's clefts are connected to the red blood cell membrane by regions with extended stalk-like profiles. Immunogold labelling with specific antibodies confirms differential labelling of the Maurer's clefts and the parasitophorous vacuole and erythrocyte membranes. Spot fluorescence photobleaching was used to demonstrate the absence of a lipid continuum between the Maurer's clefts and parasite membranes and the host plasma membrane.

The virulence of the malaria parasitePlasmodium falciparumis related to its ability to express a family of adhesive proteins known asP. falciparumerythrocyte membrane protein 1 (PfEMP1) at the infected red blood cell surface. The mechanism for the transport and delivery of these adhesins to the erythrocyte membrane is only poorly understood. In this work, we have used specific immune reagents in a flow cytometric assay to monitor the effects of serum components on the surface presentation of PfEMP1. We show that efficient presentation of the A4 and VAR2CSA variants of PfEMP1 is dependent on the presence of serum in the bathing medium during parasite maturation. Lipid-loaded albumin supports parasite growth but allows much less efficient presentation of PfEMP1 at the red blood cell surface. Analysis of the serum components reveals that lipoproteins, especially those of the low-density lipoprotein fraction, promote PfEMP1 presentation. Cytoadhesion of infected erythrocytes to the host cell receptors CD36 and ICAM-1 is also decreased in infected erythrocytes cultured in the absence of serum. The defect appears to be in the transfer of PfEMP1 from parasite-derived structures known as the Maurer's clefts to the erythrocyte membrane or in surface conformation rather than a down-regulation or switching of particular PfEMP1 variants.

In many cnidarians, symbiotic algae live within host-derived symbiosomes. We determined whether a symbiosome membrane alters the response of isolated symbiotic algae to two signalling compounds that regulate algal carbon metabolism. Host release factor (HRF), which stimulates photosynthate release, and photosynthesis inhibiting factor (PIF), which inhibits photosynthetic carbon fixation, are found in homogenised tissue of the scleractinian coral Plesiastrea versipora. Compared with seawater controls, photosynthate release from isolated algae incubated in P. versipora homogenate for 2 h in the light was: 6 to 19-fold higher from its own algae (free of symbiosomes); 19 to 32-fold higher from Zoanthid robustus algae (within symbiosomes) and 3 to 24-fold higher from Z. robustus algae (free of symbiosomes); and from cultured algae (free of symbiosomes) was seven-fold higher from Montipora verrucosa and four-fold higher from Cassiopeia xamachana. Incubation of algae in P. versipora homogenate inhibited photosynthesis by: 33–49% in P. versipora algae; 29–47% in Z. robustus algae (regardless of whether or not the symbiosome was present); and 25% in M. verrucosa algae. In C. xamachana algae, photosynthesis increased. We conclude that the symbiosome is not essential for, yet does not block, the effects of HRF and PIF.

Blue and green morphs of the scleractinian coral Plesiastrea versipora were exposed to increasing amounts of copper for periods of 12 (0–5.04 μM) to 36 d (two cycles of 0–7.55 μM). Algae were not expelled and there was no decrease in photosynthesis or chlorophyll a . Chlorophyll c decreased in only one out of four experiments. Total carotenoids increased in all the experiments. Two host signalling compounds that regulate algal carbon metabolism, host release factor (HRF) which stimulates algal photosynthate release, and photosynthesis inhibiting factor (PIF) which partially inhibits photosynthetic carbon fixation, were examined. PIF activity was slightly higher after 16 and 36 d of exposure to copper, but HRF activity was always similar to seawater control corals. Algae isolated from corals previously exposed to copper showed a variable response. In one experiment (12 d exposure), algae were not inhibited by PIF and stimulation by HRF was lower than in algae isolated from seawater control corals. In another experiment (36 d exposure), algae still responded to HRF but were less responsive to PIF. In parallel with the length of exposure to copper, oxidative damage was evident in coral tissues, as a decrease in the levels of tryptophan (up to 34%) and coral fluorophores (16–88%). This study shows that changes in fluorescent compounds can give an early indication of copper-induced damage in this coral before damage is outwardly visible. This is the first study to show that copper may alter algal responses to two host signalling compounds that regulate symbiotic algae.

Background. In 2010, mass vaccination with a then-new meningococcal A polysaccharide–tetanus toxoid protein conjugate vaccine (PsA-TT, or MenAfriVac) was undertaken in 1- to 29-year-olds in Bamako, Mali. Whether vaccination with PsA-TT effectively boosts tetanus immunity in a population with heterogeneous baseline tetanus immunity is not known. We assessed the impact of PsA-TT on tetanus toxoid (TT) immunity by quantifying age- and sex-specific immunity prior to and 2 years after introduction. Methods. Using a household-based, age-stratified design, we randomly selected participants for a prevaccination serological survey in 2010 and a postvaccination survey in 2012. TT immunoglobulin G (IgG) antibodies were quantified and geometric mean concentrations (GMCs) pre- and postvaccination among all age groups targeted for vaccination were compared. The probability of TT IgG levels ≥0.1 IU/mL (indicating short-term protection) and ≥1.0 IU/mL (indicating long-term protection) by age and sex was determined using logistic regression models. Results. Analysis of 793 prevaccination and 800 postvaccination sera indicated that while GMCs were low pre–PsA-TT, significantly higher GMCs in all age–sex strata were observed 2 years after PsA-TT introduction. The percentage with short-term immunity increased from 57.1% to 88.4% (31.3-point increase; 95% confidence interval [CI], 26.6–36.0;, P < .0001) and with long-term immunity increased from 20.0% to 58.5% (38.5-point increase; 95% CI, 33.7–43.3; P < .0001) pre- and postvaccination. Conclusions. Significantly higher TT immunity was observed among vaccine-targeted age groups up to 2 years after Mali's PsA-TT mass vaccination campaign. Our results, combined with evidence from clinical trials, strongly suggest that conjugate vaccines containing TT such as PsA-TT should be considered bivalent vaccines because of their ability to boost tetanus immunity.

BRCA1-associated protein 1 (BAP1), which is frequently mutated in cancer, functions as a deubiquitinase (DUB) for histone H2A. Although BAP1 interacts with a transcriptional regulator, HCF-1, and transcription factors FoxK1 and FoxK2, how BAP1 controls gene expression remains unclear. This study investigates the importance of BAP1 DUB activity and the interactions with FoxK2 and HCF-1 in the regulation of FoxK2 target genes. We show that FoxK2 recruits BAP1 to the target genes through the forkhead-associated domain, which interacts with Thr(P)-493 on BAP1. BAP1, in turn, recruits HCF-1, thereby forming a ternary complex in which BAP1 bridges FoxK2 and HCF-1. BAP1 represses FoxK2 target genes, and this effect requires BAP1 DUB activity but not interaction with HCF-1. Importantly, BAP1 depletion causes up-regulation of FoxK2 target genes only in the presence of the Ring1B-Bmi1 complex, an E3 ubiquitin ligase for histone H2A, indicating an antagonizing role of BAP1 against Ring1B-Bmi1. Our findings suggest that BAP1 deficiency causes increased expression of target genes in a Ring1B-Bmi1-dependent manner.

X-ray tomography can provide structural information of whole cells in close to their native state. Radiation-induced damage, however, imposes a practical limit to image resolution, and as such, a choice between damage, image contrast, and image resolution must be made. New coherent diffractive imaging techniques, such Fresnel Coherent Diffractive Imaging (FCDI), allows quantitative phase information with exceptional dose efficiency, high contrast, and nano-scale resolution. Here we present three-dimensional quantitative images of a whole eukaryotic cell by FCDI at a spatial resolution below 70 nm with sufficient phase contrast to distinguish major cellular components. From our data, we estimate that the minimum dose required for a similar resolution is close to that predicted by the Rose criterion, considerably below accepted estimates of the maximum dose a frozen-hydrated cell can tolerate. Based on the dose efficiency, contrast, and resolution achieved, we expect this technique will find immediate applications in tomographic cellular characterisation.

A national seroprevalence study was performed to determine the prevalence of Haemophilus influenzae type b (Hib) antibodies in England and Wales in 2009, when Hib disease incidence was the lowest ever recorded. A total of 2,693 anonymised residual sera from routine diagnostic testing submitted by participating National Health Service hospital laboratories were tested for Hib anti-polyribosyl-ribitol phosphate (PRP) IgG antibodies using a fluorescent bead assay. Median anti-PRP IgG concentrations were highest in toddlers aged 1-4 years (2.65 µg/ml), followed by children aged 5-9 years (1.95 µg/ml). Antibody concentrations were significantly lower after this age, but were still significantly higher among 10-19 year-olds (0.54 µg/ml) compared with adults aged >20 years (0.16 µg/ml; p

Cnidarian cell signalling remains poorly understood. This study has expanded our knowledge of the cell signalling molecule host release factor (HRF) from the coral Plesiastrea versipora. We have now confirmed that HRF is present in coral host cells that lack intracellular algae. Previous studies showed that HRF stimulates the release of photosynthetic products (mainly glycerol) from Symbiodinium algae, thus providing the host with carbon; glycerol release was accompanied by reduced synthesis of algal triacylglycerols and starch. In this study, we have shown that supplying glycerol to algae incubated with HRF does not restore normal triacylglycerol and starch synthesis. Release of (14) C-labelled products from algae may continue after photosynthesis ceases, although at a much lower rate. When algae were placed in the dark for 4 h with HRF following 2 h of photosynthesis in seawater, (14)C-labelled products were released, but at ≤ 15% of the amount released during 2 h of photosynthesis with HRF. HRF did not stimulate the release of compounds derived from a nonphotosynthetic source. The response of Symbiodinium from P. versipora to HRF has been compared with the response of Symbiodinium algae from Tridacna maxima, Heliofungia actiniformis, Aiptasia pulchella and Pocillopora damicornis to both their own HRF and to P. versipora HRF. Algae from P. versipora showed the highest response to both P. versipora HRF and to the other hosts' HRF. Further purification of P. versipora HRF suggests that HRF is a peptide with an acidic pI. We propose that HRF will provide a useful tool for the study of carbon metabolism.

Lunasin is a 43-amino acid naturally occurring chemopreventive peptide with demonstrated anti-cancer and anti-inflammatory properties. The objectives of this study were to determine the effect of temperature on the secondary structure of lunasin, to develop a method of isolating lunasin from human plasma using an ion-exchange microspin column and to quantify the amount of lunasin using an optimized enzyme-linked immunosorbent assay. Lunasin was purified using a combination of ion-exchange chromatography, ultrafiltration and gel filtration chromatography. Circular dichroism showed that increased in temperature from 25 to 100 °C resulted in changes on the secondary structure of lunasin and its capability to interact with rabbit polyclonal antibody. Enzyme linked immunosorbent assay showed that lunasin rabbit polyclonal antibody has a titer of 250 and a specific activity of 0.05 mL/μg. A linear response was detected between 16 to 48 ng lunasin per mL ( y = 0.03 x − 0.38, R 2 = 0.96). The use of diethylaminoethyl microspin column to isolate spiked lunasin in human plasma showed that most lunasin (37.8–46.5%) bound to the column eluted with Tris–HCl buffer, pH 7.5 with a yield up to 76.6%. In conclusion, lunasin can be isolated from human plasma by a simple DEAE microspin column technique and can be quantified using a validated and optimized immunoassay procedure. This method can be used directly to quantify lunasin from plasma in different human and animal studies aiming to determine its bioavailability.

During intraerythrocytic development, the human malaria parasite, Plasmodium falciparum, establishes membrane-bound compartments, known as Maurer's clefts, outside the confines of its own plasma membrane. The Maurer's compartments are thought to be a crucial component of the machinery for protein sorting and trafficking; however, their ultrastructure is only partly defined. We have used electron tomography to image Maurer's clefts of 3D7 strain parasites. The compartments are revealed as flattened structures with a translucent lumen and a more electron-dense coat. They display a complex and convoluted morphology, and some regions are modified with surface nodules, each with a circular cross-section of approximately 25 nm. Individual 25 nm vesicle-like structures are also seen in the erythrocyte cytoplasm and associated with the red blood cell membrane. The Maurer's clefts are connected to the red blood cell membrane by regions with extended stalk-like profiles. Immunogold labelling with specific antibodies confirms differential labelling of the Maurer's clefts and the parasitophorous vacuole and erythrocyte membranes. Spot fluorescence photobleaching was used to demonstrate the absence of a lipid continuum between the Maurer's clefts and parasite membranes and the host plasma membrane.

The immune response against the Plasmodium falciparum variant surface antigen P. falciparum erythrocyte membrane protein 1 (PfEMP1) is a key component of clinical immunity against falciparum malaria. In this study, we used sera from human volunteers who had been infected with the P. falciparum 3D7 strain to investigate the development, specificity, and dynamics of anti-PfEMP1 antibodies measured against six different strain 3D7 Duffy binding-like domain 1α (DBL1α) fusion proteins. We observed that a parasitemia of 20 to 200 infected erythrocytes per μl was required to trigger an antibody response to DBL1α and that antibodies against one DBL1α variant cross-react with other DBL1α variants. Both serum and purified immunoglobulin Gs (IgGs) were able to agglutinate infected erythrocytes, and purified anti-DBL1α IgGs bound to the live infected red blood cell surface in a punctate surface pattern, confirming that the IgGs recognize native PfEMP1. Analysis of sera from tourists naturally infected with P. falciparum suggests that the anti-PfEMP1 antibodies often persisted for more than 100 days after a single infection. These results help to further our understanding of the development of acquired immunity to P. falciparum infections.

The malaria parasite, Plasmodium falciparum, exports proteins beyond the confines of its own plasma membrane, however there is debate regarding the machinery used for these trafficking events. We have generated transgenic parasites expressing chimeric proteins and used immunofluorescence studies to determine the locations of plasmodial homologues of the COPII component, Sar1p, and the Golgi-docking protein, Bet3p. The P. falciparum Sar1p (PfSar1p) chimeras bind to the endoplasmic reticulum surface and define a network of membranes wrapped around parasite nuclei. As the parasite matures, the endomembrane systems of individual merozoites remain interconnected until very late in schizogony. Antibodies raised against plasmodial Bet3p recognise two foci of reactivity in early parasite stages that increase in number as the parasite matures. Some of the P. falciparum Bet3p (PfBet3p) compartments are juxtaposed to compartments defined by the cis Golgi marker, PfGRASP, while others are distributed through the cytoplasm. The compartments defined by the trans Golgi marker, PfRab6, are separate, suggesting that the Golgi is dispersed. Bet3p-green fluorescent protein (GFP) is partly associated with punctate structures but a substantial population diffuses freely in the parasite cytoplasm. By contrast, yeast Bet3p is very tightly associated with immobile structures. This study challenges the view that the COPII complex and the Golgi apparatus are exported into the infected erythrocyte cytoplasm.

Background Although a combined Haemophilus influenzae type b (Hib)/meningococcal capsular group C (MenC) conjugate vaccine with a tetanus toxoid carrier protein (Hib/MenC-TT) is not licensed for use in those above 2 years of age due to lack of data on safety and efficacy, certain patient groups at high risk of MenC and/or Hib disease are recommended to receive it. Laboratory workers working with Hib and/or MenC cultures may be at a potentially increased risk of acquiring infectious diseases and vaccination is therefore an important safety consideration. We undertook a clinical trial to investigate the safety and immunogenicity of Hib/MenC-TT vaccine in this cohort. Methods A total of 33 subjects were recruited to the trial, all of whom were vaccinated. Serology was completed on samples taken at baseline and four weeks following vaccination to determine MenC specific IgG, MenC serum bactericidal antibody (SBA), anti-Hib polyribosylribitol phosphate (PRP) IgG and anti-tetanus toxoid IgG responses. Results At baseline, high proportions of subjects had protective antibody concentrations against MenC, Hib and tetanus due to previous vaccination and/or natural exposure. Vaccination induced > 3, 10 and 220 fold increases in geometric mean concentrations for MenC SBA, anti-tetanus toxoid IgG and anti-Hib PRP IgG, respectively. Following vaccination, 97% of subjects had putative protective SBA titres ≥ 8, 100% had short term protective anti-Hib PRP IgG concentrations ≥ 0.15 μg/mL and 97% had protective anti-tetanus toxoid concentrations ≥ 0.1 IU/mL. No safety concerns were reported with minor local reactions being reported by 21% of subjects. Conclusions Immunological responses determined in this trial are likely a combination of primary and secondary responses due to previous vaccination and natural exposure. Subjects were a representative cross-section of laboratory workers, enabling us to conclude that a single dose of Hib/MenC-TT was safe and immunogenic in healthy adults providing the evidence that this vaccine may be used for providing protection in an occupational setting.