Recognition of viral glycoproteins by influenza A-specific cross- reactive cytolytic T lymphocytes

Two populations of cytolytic T lymphocytes (CTL) generated after influenza A virus infection can be distinguished into one with specificity for the sensitizing hemagglutinin type and a second with cross-reactivity for antigens induced by other type-A influenza viruses. The molecules carrying the antigenic determinants recognized by the cross-reactive CTL were studied. In L-929 cells abortively infected with fowl plague virus, matrix (M) protein synthesis is specifically inhibited, whereas the envelope glycoproteins, hemagglutinin and neuraminidase, are synthesized and incorporated into the plasma membrane. These target cells were lysed by cross-reactive CTL. The envelope proteins of type A/Victoria virus were separated from the other virion components and reconstituted into lipid vesicles that lacked M protein that subsequently were used to prepare artificial target cells. Target-cell formation with vesicles was achieved by addition of fusion-active Sendai virus. These artificial target cells were also susceptible to lysis by cross-reactive CTL. In contrast to previous observations that suggested that the M protein of influenza viruses is recognized by these effector cells, we present evidence that the antigencic determinants induced by the viral glycoproteins are recognized

The role of TcdB and TccC subunits in secretion of the photorhabdus Tcd toxin complex

The Toxin Complex (TC) is a large multi-subunit toxin encoded by a range of bacterial pathogens. The best-characterized examples are from the insect pathogens Photorhabdus, Xenorhabdus and Yersinia. They consist of three large protein subunits, designated A, B and C that assemble in a 5:1:1 stoichiometry. Oral toxicity to a range of insects means that some have the potential to be developed as pest control technology. The three subunit proteins do not encode any recognisable export sequences and as such little progress has been made in understanding their secretion. We have developed heterologous TC production and secretion models in E. coli and used them to ascribe functions to different domains of the crucial B+C sub-complex. We have determined that the B and C subunits use a secretion mechanism that is either encoded by the proteins themselves or employ an as yet undefined system common to laboratory strains of E. coli. We demonstrate that both the N-terminal domains of the B and C subunits are required for secretion of the whole complex. We propose a model whereby the N-terminus of the C-subunit toxin exports the B+C sub-complex across the inner membrane while that of the B-subunit allows passage across the outer membrane. We also demonstrate that even in the absence of the B-subunit, that the C-subunit can also facilitate secretion of the larger A-subunit. The recognition of this novel export system is likely to be of importance to future protein secretion studies. Finally, the identification of homologues of B and C subunits in diverse bacterial pathogens, including Burkholderia and Pseudomonas, suggests that these toxins are likely to be important in a range of different hosts, including man

PHLD 9231 – Health Informatics & Decision Making

This course focuses on the fundamental concepts of managing information as an asset in public health and healthcare delivery contexts. Emphasis will be placed on converting data into information and converting information into decision support models

Public Health Agencies’ Health Informatics Capacity and Its Impact on Activities to Address Health Disparities

This study examines LHDs’ activities and strategies that seek to address health disparities and inequities and whether the LHDs’ informatics capacities shape the likelihood of performing those activities

Expressed sequence tags from \u3ci\u3eDiabrotica virgifera virgifera\u3c/i\u3e midgut identify a coleopteran cadherin and a diversity of cathepsins

The Western corn rootworm is the major pest of corn in the USA and has recently become the target for insect-resistant transgenic crops. Transgenic crops have switched the focus for identifying insecticide targets from the insect nervous system to the midgut. Here we describe a collection of 691 sequences from the Western corn rootworm midgut, 27% of which predict proteins with no matches in current databases. Of the remaining sequences, most predict proteins with either catalytic (62%) or binding (19%) functions, as expected for proteins expressed in the insect midgut. The utility of this approach for the identification of targets for novel toxins is demonstrated by analysis of the first coleopteran cadherin gene, a putative Bt receptor, and a large class of cysteine-proteases, the cathepsins

Expressed sequence tags from \u3ci\u3eDiabrotica virgifera virgifera\u3c/i\u3e midgut identify a coleopteran cadherin and a diversity of cathepsins

The Western corn rootworm is the major pest of corn in the USA and has recently become the target for insect-resistant transgenic crops. Transgenic crops have switched the focus for identifying insecticide targets from the insect nervous system to the midgut. Here we describe a collection of 691 sequences from the Western corn rootworm midgut, 27% of which predict proteins with no matches in current databases. Of the remaining sequences, most predict proteins with either catalytic (62%) or binding (19%) functions, as expected for proteins expressed in the insect midgut. The utility of this approach for the identification of targets for novel toxins is demonstrated by analysis of the first coleopteran cadherin gene, a putative Bt receptor, and a large class of cysteine-proteases, the cathepsins

Pdl1 Is a Putative Lipase that Enhances Photorhabdus Toxin Complex Secretion

The Toxin Complex (TC) is a large multi-subunit toxin first characterized in the insect pathogens Photorhabdus and Xenorhabdus, but now seen in a range of pathogens, including those of humans. These complexes comprise three protein subunits, A, B and C which in the Xenorhabdus toxin are found in a 4∶1∶1 stoichiometry. Some TCs have been demonstrated to exhibit oral toxicity to insects and have the potential to be developed as a pest control technology. The lack of recognisable signal sequences in the three large component proteins hinders an understanding of their mode of secretion. Nevertheless, we have shown the Photorhabdus luminescens (Pl) Tcd complex has been shown to associate with the bacteria's surface, although some strains can also release it into the surrounding milieu. The large number of tc gene homologues in Pl make study of the export process difficult and as such we have developed and validated a heterologous Escherichia coli expression model to study the release of these important toxins. In addition to this model, we have used comparative genomics between a strain that releases high levels of Tcd into the supernatant and one that retains the toxin on its surface, to identify a protein responsible for enhancing secretion and release of these toxins. This protein is a putative lipase (Pdl1) which is regulated by a small tightly linked antagonist protein (Orf53). The identification of homologues of these in other bacteria, linked to other virulence factor operons, such as type VI secretion systems, suggests that these genes represent a general and widespread mechanism for enhancing toxin release in Gram negative pathogens

Fusion of Sendai virus with the target cell membrane is required for T cell cytotoxicity

INFECTION of mice with viruses can generate cytotoxic T lymphocytes (CTL) which show restricted specificity for target cell lysis. Specific lysis requires that the virus used to prime the target cells must be of the same type as that used to sensitise the CTL, and that both target and CTL cells must express the same major histocompatability complex (MHC) gene product(s). The nature of the viral gene product(s) and their interaction with the MHC gene product(s) have been the subject of recent stud1−5. Previously we used Sendai virus to show that lysable target cells can be obtained using membrane vesicles which contain only the viral glycoproteins, indicating that these may be the specific viral gene products involved in target formation5. Sendai virus contains two glycoproteins—the haemagglutinin-neuraminidase (HANA) which promotes attachment of virus to cells and the fusion protein (F) which is involved in subsequent virus cell fusion7−9. Both activities are necessary for insertion of these viral glycoproteins into the plasma membrane of the cell10. In this letter we suggest that the insertion of the viral glycoproteins into the cell membrane is an essential step in target cell formation since we can show that virus containing an inactive fusion protein precursor (F0) cannot elicit T cell cytotoxicity unless the fusion activity is generated by proteolytic cleavage of the precursor. Sugamura et al. 6 have suggested that it is primarily the F glycoprotein of the Sendai virus envelope which is essential for the formation of the target antigen, as virus lacking the functional activities of F following trypsin digestion was inactive in priming target cells for T cell killing. However, we show that proteolytic inactivation of either of the two glycoproteins (F or HANA) of virus used to prime target cells will abolish the cytotoxic response

A Nationwide Study of the “July Effect” Concerning Postpartum Hemorrhage and Its Risk Factors at Teaching Hospitals across the United States

Objective To assess the “July effect” and the risk of postpartum hemorrhage (PPH) and its risk factors across the U.S. teaching hospitals. Method This study used the 2018 Nationwide Inpatient Sample (NIS) and included 2,056,359 of 2,879,924 single live-birth hospitalizations with low-risk pregnancies across the U.S. teaching hospitals. The International Classification of Diseases, Tenth Revision (ICD-10) from the American Academy of Professional Coders (AAPC) medical coding was used to identify PPH and other study variables. Multivariable logistic regression models were used to compare the adjusted odds of PPH risk in the first and second quarters of the academic year vs. the second half of the academic year. Results Postpartum hemorrhage occurred in approximately 4.19% of the sample. We observed an increase in the adjusted odds of PPH during July through September (adjusted odds ratios (AOR), 1.05; confidence interval (CI), 1.02–1.10) and October through December (AOR, 1.07; CI, 1.04–1.12) compared to the second half of the academic year (January to June). Conclusions This study showed a significant “July effect” concerning PPH. However, given the mixed results concerning maternal outcomes at the time of childbirth other than PPH, more research is needed to investigate the “July effect” on the outcomes of the third stage of labor. This study’s findings have important implications for patient safety interventions concerning MCH