Sequence analyses of feline B7 costimulatory molecules.

Using RT-PCR amplifications with mRNA from mitogen-stimulated feline peripheral blood mononuclear cells, cDNA of feline B7-1 (CD80) and B7-2 (CD86) were cloned. The cDNA were sequenced and putative translated protein sequences compared with known counterpart sequences. Hydrophilicity patterns of the feline CD80 and CD86 which were only 26.8% identical at the amino acid sequence were very distinct from each other, but similar to the putative human CD80 and CD86 proteins, respectively. The feline CD80 gene encoded a protein of 292 amino acids and the CD86 gene encoded a protein of 329 amino acids. Amino-terminal signal sequences, extracellular Ig V- and Ig C-like domains, transmembrane domains, and carboxyl cytoplasmic domains were identified in both molecules. Although the most conserved domain among the CD80 sequences was the Ig C-like domain, the most conserved domain among the CD86 sequences was the Ig V-like domain. Among the known sequences, the bovine CD80 and the porcine CD86 sequences available for comparisons were identified as most closely related to the feline CD80 (63.3%) and CD86 (67.5%), respectively. The mouse molecules were the least identical (43.6 and 43.6%, respectively) with the feline CD80 and CD86 proteins. The human CD80 and CD86 molecules were 56.3 and 57.0% identical with the feline molecules.

Embryo vaccination of turkeys against Newcastle disease infection with recombinant fowlpox virus constructs containing interferons as adjuvants.

Recombinant fowlpox viruses (rFPV) expressing the fusion and hemagglutinin-neuraminidase glycoproteins of Newcastle disease virus (NDV) as well as chicken type I interferon (IFN) or type II IFN were used to vaccinate specific pathogen-free (SPF) turkeys in ovo. No significant changes in the hatchability, survival rate, performance and weight gain were observed after vaccination with the rFPV vaccines in comparison to diluent-inoculated embryos. The rFPV-NDV-IFN-II construct induced the onset of anti-NDV antibody production in SPF birds at one week post hatch, one week earlier than other vaccine constructs. Three to five weeks post hatch, the turkeys were challenged with the neurotropic velogenic NDV strain Texas GB (NDV-GB-Tx). The rFPV-NDV-IFN-II construct was the most protective vaccine against NDV. rFPV vaccines significantly (p<0.05) suppressed the mitogenic response of peripheral blood leukocytes in vaccinated turkeys in comparison to placebo inoculated controls at 25 days post vaccination. Birds vaccinated with rFPV-NDV-IFN-I construct did not have an inhibition in the mitogenic response.

In vitro effects of recombinant chicken interferon-gamma on immune cells.

We used the recombinant chicken interferon-gamma (ChIFN-gamma) to determine its in vitro effects on chicken immune cells. We found that ChIFN-gamma induced nitric oxide (NO) production, upregulated Ia expression on the cell surface, and inhibited the replication of Newcastle disease virus in NCSU and HD11 cells (chicken macrophage cell lines). In addition, ChIFN-gamma had an antiproliferative effect on RP9 cells, a chicken B cell line. Finally, ChIFN-gamma inhibited mitogenic proliferation of normal chicken spleen cells and induced the cells to generate NO. Inhibition of viral replication and mitogenic proliferation of normal cells were correlated with NO production. We conclude that recombinant chicken ChIFN-gamma modulates chicken immune cells.

Recombinant fowlpox viruses coexpressing chicken type I IFN and Newcastle disease virus HN and F genes: influence of IFN on protective efficacy and humoral responses of chickens following in ovo or post-hatch administration of recombinant viruses.

We have constructed recombinant (r) fowl pox viruses (FPVs) coexpressing chicken type I interferon (IFN) and/or hemagglutinin-neuraminidase (HN) and fusion (F) proteins of Newcastle disease virus (NDV). We administered rFPVs and FPV into embryonated chicken eggs at 17 days of embryonation or in chickens after hatch. Administration of FPV or rFPVs did not influence hatchability and survival of hatched chicks. In ovo or after hatch vaccination of chickens with the recombinant viruses resulted in protection against challenge with virulent FPV and NDV. Chickens vaccinated with FPV or FPV-NDV recombinant had significantly lower body weight 2 weeks following vaccination. This loss in body weight was not detected in chickens receiving FPV-IFN and FPV-NDV-IFN recombinants. Chickens vaccinated with FPV coexpressing IFN and NDV genes produced less antibodies against NDV in comparison with chickens vaccinated with FPV expressing NDV genes.

Conceptualizing vulnerable populations health-related research.

BACKGROUND: A conceptual model for vulnerable populations research relates resource availability and relative risk to health status. The model has a population-based focus that places responsibility for the collective health status of its citizens with the community. Vulnerable populations are social groups who experience limited resources and consequent high relative risk for morbidity and premature mortality. There is considerable research evidence to support the major relationships in the model. Conceptual links that need additional research are identified. CONCLUSIONS: The implications for research include a variety of methodological problems related to recruiting and retaining participants, instrumentation, and data collection. Research designs are needed that move beyond descriptive and epidemiological approaches to interventional and outcome studies. Ethical considerations take on special significance with vulnerable populations.

HIV-1 latency due to the site of proviral integration.

Cell lines that are nonproductively infected with human immunodeficiency virus type 1 (HIV-1), such as the T-lymphocyte ACH2 clone, have been proposed to represent in vitro models of proviral latency. We have previously shown that such cells exhibit an aberrant pattern of viral RNA expression, with a large excess of fully spliced viral RNAs. Here, by superinfecting the ACH2 cells with a second HIV-1 virus, we demonstrate the primary mechanism of HIV-1 proviral latency in this cell line. In the dually infected cells, the exogenous virus was transcribed at high levels. However, expression from the provirus originally present in the ACH2 cells was not quantitatively increased. Still, its RNA production was shifted from a blocked early-stage to a fully productive pattern. This was interpreted to be a consequence of the high levels of Rev produced by the exogenous virus, acting in trans to promote the cytoplasmic export of all incompletely spliced viral mRNAs made in the cells. Comparable numbers of copies of each provirus were present in the dually infected cells, and both viruses grew equally well, once passed onto fresh cells. These results indicate that the low levels of transcriptional activity of the HIV-1 virus present in ACH2 cells are secondary to specific characteristics of the region of the cellular genome in which the proviral DNA is integrated.

The blocks to human immunodeficiency virus type 1 Tat and Rev functions in mouse cell lines are independent.

Rodent cells present two blocks precluding the expression of the human immunodeficiency virus type 1 (HIV-1) genome. First, the viral protein Tat is only poorly active in these cells. Second, when the HIV-1 provirus is integrated in the genome of mouse cells, it electively fails to express the viral structural proteins, indicating a block to Rev action. Both defects can be complemented by fusion of the infected mouse cells with uninfected human cells. Because the production of high levels of Rev is dependent on Tat-mediated transactivation and because both Tat and Rev bind the viral transcript, it has been hypothesized that the two blocks found in rodent cells might be linked. In the present work, we demonstrate that overexpression of Rev in mouse cell lines does not relieve their block in HIV-1 structural-gene expression. In addition, we show that this defect is also present in human-mouse cell hybrids which contain human chromosome 12 and support Tat function. On that basis, we conclude that the blocks to HIV-1 Tat and Rev action in mouse cell lines are independent and result from the absence of distinct cellular elements that are critical for HIV-1 gene expression.

Integrity and compromise in nursing ethics.

Nurses are often caught in the middle of what appear to be intractable moral conflicts. For such times, the function and limits of moral compromise need to be explored. Compromise is compatible with moral integrity if a number of conditions are met. Among these are the sharing of a moral language, mutual respect on the part of those who differ, acknowledgement of factual and moral complexities, and recognition of limits to compromise. Nurses are in a position uniquely suited to leadership in fostering an environment that makes compromise with integrity possible.