Special-Fed Veal: Separable components, proximate composition, and nutrient analysis of selected raw and cooked, wholesale and retail cuts.

Nutrition research continues to be important for consumers to make informed food purchasing decisions and is used in nutrition policy decisions. The objective of this study was to analyze the nutrient concentration of raw and cooked cuts from special-fed veal calves to update nutrient data in the USDA National Nutrient Database for Standard Reference (SR) Release 27. Packages of wholesale (whole loin roasts, center-cut hindshanks and ground veal) and retail veal cuts (osso buco foreshanks, loin chops, leg cutlets and shoulder blade chops) were randomly collected in original vacuum packaging from six U.S. suppliers. Packages were shipped to the Colorado State University Meat Laboratory for cut dissection, cooking, and nutrient analysis. Composites of lean, external fat and seam fat were formed for analysis of proximate, fatty acid, vitamin and mineral composition. Results from this study identified additional fatty acids, established choline concentration, and provided updated veal nutrient composition information for inclusion in USDA SR 27.

The effects of molybdenum water concentration on feedlot performance, tissue mineral concentrations, and carcass quality of feedlot steers,.

Thirty cross-bred steers (initial BW 452.0 ± 12.1 kg) were used to investigate the effects of Mo water concentration on performance, carcass characteristics, and mineral status of feedlot steers. The experimental design was a randomized complete block design. Steers were blocked by weight and then divided into 2 weight blocks each consisting of 15 steers. Steers were randomly assigned within block to one of 5 treatments (3 steers/treatment per block). Water treatments consisted of: 1) 0.0 µg/L, 2) 160 µg/L, 3) 320 µg/L, 4) 480 µg/L, and 5) 960 µg/L of supplemental Mo added as Na2MoO4 to the drinking water. Steers were housed in individual pens (steer = experimental unit) that contained individual 265 L water tanks for monitoring water intake. Steers were fed a growing diet for 28 d and then transitioned to a finishing diet. Block 1 steers were fed for a total of 151 d and block 2 steers were fed for a total of 112 d. Daily water intake was recorded for each steer. Steers were individually weighed on 2 consecutive days at the beginning and end of the experiment and interim weights and jugular blood samples were obtained every 28 d. Liver biopsies were obtained on d 0 and 84 from each steer within each block. Steers were transported to a commercial abattoir, slaughtered, and individual carcass data and liver samples were collected. Initial BW was used as a covariate for statistical analysis of data and significance was determined at P ≤ 0.05. No differences were observed for final BW (P > 0.98). Overall ADG (P > 0.91), DMI (P > 0.92), feed efficiency (P > 0.94), water intake (P > 0.40), hot carcass weight (P > 0.98), dressing percentage (P > 0.98), yield grade (P > 0.91), and marbling score (P > 0.29) did not differ across treatments. Lastly, no treatment differences were observed for liver concentrations of Cu (P > 0.93), Mo (P > 0.90) and Zn (P > 0.86) or plasma concentrations of Cu (P > 0.42), Mo (P > 0.43) and Zn (P > 0.62). These data indicate that water Mo concentration, within the range studied, had no impact on performance, mineral status, water intake, and carcass characteristics in feedlot steers.

Recombinant canine IL-13 receptor alpha2-Fc fusion protein inhibits canine allergen-specific-IgE production in vitro by peripheral blood mononuclear cells from allergic dogs.

Human IL-13, like IL-4, is involved in the regulation of B-cell development, IgE synthesis and allergic responses. However, because IL-13 does not affect either murine Ig class switching or IgE production in vitro, the use of murine models to study the role of IL-13 in IgE-mediated diseases has been limited. In this communication, we report that recombinant protein of canine IL-13 (rcaIL-13) stimulates production of allergen-specific-IgE in vitro by peripheral blood mononuclear cells (PBMC) from flea allergen-sensitized dogs, and that this stimulation activity is specifically inhibited by recombinant protein of canine IL-13Ralpha2 and Fc fragment of canine IgG heavy chain (rcaIL-13Ralpha2-Fc). The data suggest that the regulatory effects of IL-13 on IgE production in canine PBMC are similar to those reported in humans. Thus, canine IL-13 may be a central mediator of allergic diseases in dogs, and allergic dogs may be excellent models for research on IgE-mediated diseases in humans.

Novel transcripts encoding secreted forms of feline CD80 and CD86 costimulatory molecules.

Engagement of costimulatory molecules such as CD28 or CD152 (CTLA4) on T cells by CD80 (B7-1) or CD86 (B7-2) dictates the nature of T cell-mediated immune responses. We previously reported the discovery of naturally occurring forms of canine CD80 and CD86 mRNAs which encode secreted CD80 and CD86 molecules. We report here that mRNAs for secreted forms of CD80 and CD86 are also expressed in cats. The mRNA for secreted feline CD86 is generated by deleting a transmembrane domain exon, which is the same mechanism we described for secreted canine CD86. We also identified a feline CD80 transcript that only retains the immunoglobulin variable-like domain. The detection of naturally occurring mRNAs encoding secreted CD80 and CD86 adds further complexity to the regulation of the B7-CD28/CD152 costimulatory pathway.

Canine interleukin-5: molecular characterization of the gene and expression of biologically active recombinant protein.

Interleukin-5 (IL-5), which is produced primarily by type 2 T helper lymphocytes (Th2), is an eosinophil differentiation and activation factor. Increased numbers of eosinophils in peripherial blood or tissues (eosinophilia) are observed in asthmatic human patients, in animals with helminth infections, and in dogs with allergic diseases. Antagonism of IL-5 activity is being explored as a potential treatment of a number of disease conditions associated with eosinophils in animal models. In order to study the expression and function of this cytokine in the dog, we have isolated and characterized the canine IL-5 gene. The canine IL-5 polypeptide deduced from the cDNA is composed of 134 amino acids that share varying degrees of homology with IL-5 isolated from several mammals. The genomic structure of the canine IL-5 gene consists of four exons and three introns in the coding region, similar to that of the previously characterized human and mouse IL-5 genes. Recombinant canine IL-5 protein, expressed in Pichia pastoris, is biologically active in a cell proliferation assay. Canine IL-5 gene sequences and the biologically active protein described in this study will be useful reagents for future studies of this cytokine in physiologic processes and in pathologic conditions of the dog.

Transcutaneous immunization of domestic animals: opportunities and challenges.

Transcutaneous immunization (TCI), the topical application of antigen and adjuvant directly onto intact skin, can safely and effectively elicit systemic immune responses in mice and humans against a variety of antigens. This novel method of vaccine delivery has the potential to provide a safe and convenient method by which vaccines may be delivered to elicit protective immunity in domestic animals. To date, however, immune responses induced by TCI in companion and production animals has not been reported. In this report, we demonstrate that TCI may be widely applicable to many animals. Immune responses elicited by TCI require further optimization for each antigen and species, and success may depend upon the structure and composition of the skin of the target species. The prospect of TCI as a practical and broadly applicable approach to vaccination in veterinary medicine is discussed in the context of these challenges.

Calpain and calpastatin regulate neutrophil apoptosis.

The average polymorphonuclear neutrophil (PMN) lives only a day and then dies by apoptosis. We previously found that the calcium-dependent protease calpain is required for apoptosis in several mouse models of cell death. Here we identify calpain, and its endogenous inhibitor calpastatin, as regulators of human neutrophil apoptosis. Cell death triggered by the translation inhibitor cycloheximide is calpain-dependent, as evidenced using either a calpain active site inhibitor (N-acetyl-leucyl-leucyl-norleucinal) or agents that target calpain's calcium binding sites (PD150606, PD151746). No significant effect on cycloheximide-triggered apoptosis was found by using inhibitors of the proteasome or of other papain-like cysteine proteases, providing further evidence that the active site calpain inhibitor prevents apoptosis via its action on calpain. In addition, we find that potentiation of calpain activity by depleting its endogenous inhibitor, calpastatin, is sufficient to cause apoptosis of neutrophils. Nevertheless, apoptosis signalled via the Fas antigen proceeds regardless of the presence of calpain inhibitor. These experiments support a growing body of work, indicating an upstream regulatory role for calpain in many, but not all, forms of apoptotic cell death. They also identify calpastatin as a participant in apoptotic cell death and suggest that for at least one cell type, a decrease in calpastatin is a sufficient stimulus to initiate calpain-dependent apoptosis.

In vivo treatment with granulocyte colony-stimulating factor results in divergent effects on neutrophil functions measured in vitro.

We have studied the effects of granulocyte colony-stimulating factor (G-CSF) administration to normal individuals on a variety of functional and biochemical neutrophil characteristics that relate to host defense. G-CSF adversely affected neutrophil (polymorphonuclear leukocyte [PMN]) chemotaxis. While this could be partially explained by reduced assembly of neutrophil F-actin, we also recognized an elevated cytosolic calcium mobilization and a normal upregulation of neutrophil CD11b. G-CSF resulted in reduced PMN killing of Staphylococcus aureus with a 10:1 (bacteria:neutrophil) ratio and normal killing with a 1:1 ratio. In association with this, we demonstrated divergent effects on the respiratory burst of intact cells and divergent effects on the content of marker proteins for neutrophil granules. While G-CSF may have resulted in increased content of cytochrome b558 in the cell membrane, it did not alter the amounts of cytosolic oxidase components. After therapy, there was normal content of the azurophilic granule marker, myeloperoxidase, decreased content of the specific granule marker, lactoferrin, and normal content of lysozyme (found in both granules classes). Finally, G-CSF therapy markedly reduced the apoptotic rate of the isolated neutrophil. Therefore, considering disparate functional and biochemical activities, the real benefit of G-CSF therapy may lie in enhanced number and survival of neutrophils.

Resistance to tolerance induction in the diabetes-prone biobreeding rat as one manifestation of abnormal responses to superantigens.

T cells taken from normal rats treated with an exogenous source of bacterial superantigen in vivo specifically failed to proliferate following re-stimulation with the same superantigen in vitro. Responsiveness was restored following the addition of an exogenous source of interleukin-2 indicating that the T cells had been made functionally tolerant and not deleted. While staphylococcal enterotoxin treatment of normal rats virtually abolished T-cell proliferation to the same enterotoxin in vitro, T cells from similarly treated diabetes-prone Biobreeding (BB-DP) rats were markedly resistant to this in vivo effect. Responses in BB-DP rats were never reduced by more than 50% even when a 4 times more effective dose of enterotoxin was employed. The resistance of BB-DP peripheral T cells to staphylococcal enterotoxin-induced tolerance could not be attributed to differences in T-cell receptor V beta chain family usage of BB-DP vs normal T cells but was associated with qualitative differences in the way in which BB-DP T cells responded to staphylococcal enterotoxins in vitro. While under optimal stimulatory conditions BB-DP T-cell proliferative responses to staphylococcal enterotoxins appeared comparable to those from non-diabetes-prone animals, under superoptimal conditions BB-DP, but not diabetes-resistant, donor T-cell proliferative responses to staphylococcal enterotoxins could be blocked in vitro with antibodies to CD4 antigens. In addition, BB-DP T-cell proliferative responses were more sensitive to suboptimal staphylococcal enterotoxin doses in vitro. We discuss ways in which abnormal BB-DP T-cell responses to superantigens in general and resistance to staphylococcal enterotoxin-mediated tolerance induction in particular may play a role in the generation of a peripheral T-cell repertoire prone to autoimmunity.

T cells from BB-DP rats show a unique cytokine mRNA profile associated with the IDDM1 susceptibility gene, Lyp.

Diabetes prone biobreeding rats display several abnormalities in T cell numbers, T cell function and T cell surface phenotype which are associated with the onset of spontaneous disease. One of the most pronounced abnormalities in these animals is a marked T cell lymphopenia which is evident in both CD4+ and CD8+ peripheral T cell subsets. To gain a better understanding as to the nature of T cell responses in these animals, we have utilized RT-PCR to analyze the cytokine mRNA profiles of mitogen activated peripheral T cells derived from lymphopenic and non-lymphopenic animals. Our results suggest that inheritance of the lymphopenia gene, Lyp, is associated with a unique cytokine profile most similar to that previously described for mouse medullary thymocytes. In addition, cell surface staining of peripheral T cells from diabetes prone animals revealed a high frequency of Thyl+ cells, which is characteristic of both thymocytes and recent thymic emigrants. Following thymectomy, T cell responsiveness to a number of different stimuli is greatly reduced on a cell for cell basis as is the absolute number of surviving T cells. Taken collectively, our results suggest that the majority of the peripheral T cell pool in these diabetic prone rats consists of short lived, recent thymic emigrants which most likely also contain the effector cells required for initiation of diabetes.

Peculiar T-cell signaling does not preclude positive selection in the diabetes-prone BB rat.

Various studies have provided evidence that peripheral T-cells from the diabetes-prone BB-DP rat are abnormal in function and cell surface phenotype. These characteristics have often been interpreted as indicators of immaturity and/or short life span. In this study, we describe a CD4-dependent signaling abnormality in BB-DP peripheral T-cells. In spite of the fact that CD4 plays a critical role in thymocyte development, the abnormal signaling does not appear to influence thymocyte development at the stage when the T-cell receptor is rearranged and the recombinase enzymes RAG-1 and RAG-2 transcripts are downregulated. Therefore, if a maturation defect leading to the seeding of the periphery with immature T-cells occurs in the BB-DP rat, it does not preclude the initial selection of the self major histocompatibility complex-restricted T-cell repertoire.

Rat T cell responses to superantigens. II. Allelic differences in V beta 8.2 and V beta 8.5 beta chains determine responsiveness to staphylococcal enterotoxin B and mouse mammary tumor virus-encoded products.

The previous paper in this series demonstrates that rat T cells developing de novo in the presence of mouse mammary tumor virus (Mtv) antigens in rat-->severe combined immunodeficiency (SCID) mouse xenochimeras display a distinct pattern of V beta-restricted deletion; this deletion pattern is remarkably similar to that occurring during thymic development of mouse T cells in Mtv+ strains. In addition, T cells developing in the absence of Mtv antigens in these rat-->mouse xenochimeras are tolerant of host antigens, but show strong primary proliferative responses in cultures stimulated with Mtv-7+ (Mlsa) mouse cells; like the mouse, these rat T cell responses are dominated by V beta 6 and V beta 8 T cells. Here, we continue analysis of rat T cell responses to superantigens; we show that T cells from Lewis and Fischer 344 rats expressing V beta 8.2 display an important all-or-nothing difference in their responses to Mtv-7 superantigens. This all-or-none strain difference in the response to Mtv-7 applies also to the response by V beta 8.2 and V beta 8.5 T cells to the soluble superantigen staphylococcal enterotoxin B. Because these two rat strains express different alleles of these two V beta 8 family members, this finding identifies additional, hitherto unreported residues of the T cell receptor beta chain important in T cell responses to superantigens.

Limited T cell receptor beta-chain usage in the sperm whale myoglobin 110-121/E alpha dA beta d response by H-2d congenic mouse strains.

The specificity and TCR gene usage of a panel of sperm whale myoglobin (SpWMb)-reactive T cell clones from DBA/2 mice have previously been characterized, to study structure-function relationships between components of the ternary complex consisting of Ag, TCR, and MHC class II molecules, whose interaction leads to Th cell activation. These DBA/2 clones were specific for epitopes within the residue 110 to 121 region of SpWMb, in the context of the mixed isotype molecule E alpha dA beta d, and expressed the TCR V beta 8.2 gene element. SpWMb-specific T cell hybridomas from the H-2d-congenic B10.D2 mouse strain, which differs from the DBA/2 strain only in the non-MHC background, were generated and compared with the T cell hybridomas from DBA/2 mice, in order to investigate the influence of non-MHC genes on the specificity of the T cell response to the 110-121 epitope. V beta usage by these hybridomas was very homogeneous; three of three DBA/2 and eight of nine B10.D2 hybridomas specific for the 110-121 epitope, in the context of the mixed isotype molecule E alpha dA beta d, expressed the V beta 8.2 gene product. Nucleotide and amino acid sequences of D beta, J beta, and N regions were also similar. One 110-121/E alpha dA beta d-specific B10.D2 hybridoma used V beta 7, a V beta that is clonally deleted in DBA/2 mice. These experiments suggest that a similar set of TCR beta genes are used to respond to a given epitope, regardless of non-MHC background, and they support the hypothesis that, despite great variability between individuals in their non-MHC background genes, human HLA-associated diseases might result from the formation of a particular ternary complex consisting of a shared MHC molecule, a common "disease-associated" epitope, and a shared TCR.

Specificity of rat T cell receptor V beta chain usage in proliferative responses to staphylococcal enterotoxin B.

The staphylococcal enterotoxins (SE) are potent stimulators of T cell proliferative responses in humans and in mice. In these systems, the toxins function as superantigens and stimulate T cells bearing particular V beta. Although homology between the V beta of mice and humans is limited, related V beta families may respond to certain SE in a similar fashion. In this report, we have characterized the rat T cell response to staphylococcal enterotoxin B (SEB). Rat T cells from several lymphoid organs proliferated strongly in response to both commercially available and recombinant SEB. Using a polymerase chain reaction assay, we identified the predominant V beta families stimulated by this enterotoxin. The T cell receptor V beta elements used by rat T cells were similar to but not completely identical with those used by mice. The V beta profile stimulated depended on the purity of the SEB preparation used.

Presentation of antigen by mixed isotype class II molecules in normal H-2d mice.

A panel of DBA/2 T cell hybridomas specific for the sperm whale myoglobin epitope 110-121 was found to recognize antigen presented by the mixed isotype class II molecule E alpha dA beta d. The response was blocked by monoclonal antibodies specific for E alpha and A beta d chains; in addition, the hybridomas responded to antigen presented by L cells expressing E alpha A beta d molecules, and made no response with L cells expressing I-Ad or I-Ed molecules. Two more groups of hybridomas isolated from DBA/2 and B10.D2 mice immunized with myoglobin also recognized peptide 110-121 presented by E alpha d A beta d. Thus, although it is expressed at biochemically undetectable levels on spleen cells, the E alpha d A beta d molecule is an important presenting element in normal H-2d mice making a conventional immune response to a protein antigen. These results suggest that high levels of class II expression are not a prerequisite for T cell activation.

Apoptosis and programmed cell death in immunity.

Death of some cells in the mammalian body is clearly programmed. In the immune system there are many examples of programmed cell death, during development of lymphocytes as well as at later stages, after interaction with antigen. Many of these examples display the morphology of apoptosis: They undergo shrinkage and zeiosis, the nucleus collapses, and chromatin is cleaved into nucleosomal fragments. The cell is rapidly recognized by phagocytes and disposed of without releasing its contents. In some but not all cases of apoptosis, new macromolecular synthesis is required. Cytotoxic T cells induce changes in their targets that are morphologically apoptotic. The mechanism of apoptosis is currently under active investigation.

Cytotoxic T lymphocytes induce different types of DNA damage in target cells of different origins.

Nuclear changes may be important in the mechanism of CTL-mediated lysis. Rapid cleavage of target cell DNA into oligonucleosomes has been demonstrated as a very early event in CTL-mediated killing of murine hematopoietic targets. However, the results presented herein and by other investigators have shown that this extensive dsDNA fragmentation does not occur in all CTL targets. In terms of actual DNA damage, there is a wide range in the extent and type of DNA cleavage in various targets. Differences exist at both the species and the cell lineage level. The extent of DNA damage generally corresponds to the efficiency of lysis; thus, murine hematopoietic cells, which undergo dsDNA fragmentation, are killed more rapidly and at lower E/T cell ratios than are murine nonhematopoietic cells, which sustain single-stranded nicks. Experiments using cloned CTL demonstrate that the same effector cell kills both hematopoietic and nonhematopoietic targets, producing different types of DNA damage. These observations indicate that the fate of the target cell DNA is determined by the nature of the target cell and not by the CTL. We propose that DNA damage results from an enzyme pathway inherent to the target, which is activated by, not transferred from, the CTL.