Search Results
You are looking at 1 - 5 of 5 items for
- Author or Editor: Lorraine M. Sordillo x
- Refine by Access: All Content x
Abstract
Objective
To examine whether specific immunity in the mammary gland and blood of dairy cattle was enhanced after primary innoculation with a test antigen keyhole limpet hemocyanin (KLH) and recombinant bovine interferon-γ (rBolFN-γ) as an adjuvant.
Design
Holstein dairy cows received IM injections of KLH in conjunction with saline solution (n = 4), Freund's incomplete adjuvant (FIA; n = 4), or rBolFN-γ (n = 3). Milk and blood samples were collected during a 1-month period and analyzed for KLH antibody content. Isolated blood mononuclear cells were examined for their ability to proliferate and produce interleukin 2 (IL-2) after mitogen and/or KLH stimulation in vitro. The phenotype of isolated blood mononuclear cells also was characterized through flow cytometric analysis.
Results
The adjuvant rBolFN-γ induced serum KLH antibody titers similar to those induced by administration of FIA. However, FIA induced significantly more KLH antibodies in milk. Administration of rBolFN-γ enhanced T-lymphocyte activity, as indicated by the greater expression of high-affinity IL-2 receptors and the increased response to the mitogens concanavalin A, phytohemagglutinin, and IL-2, compared with FIA or saline treatment. Lymphocyte and monocyte movement from the blood also was altered after rBolFN-γ treatment, which can have a profound influence on secondary immune responses, such as antibody production.
Conclusions
rBolFN-γ may safely enhance specific immunity in the bovine mammary gland and may be an effective adjuvant in mastitis immunization protocols. (Am J Vet Res 1996;57:819–824)
Abstract
Objective—To determine effects of infection with bovine leukosis virus (BLV) on lymphocyte proliferation and apoptosis in dairy cattle.
Animals—27 adult Holstein cows.
Procedures—Peripheral blood mononuclear cells (PBMCs) were isolated from whole blood from lactating Holstein cows seronegative for BLV (n = 9 cows), seropositive for BLV and aleukemic (aleukemic; 9), and seropositive for BLV and persistently lymphocytotic (PL; 9). Isolated PBMCs were assayed for mitogen-induced proliferation and were analyzed by means of flow cytometry. The PBMCs from a subset of each group were assayed for apoptosis, caspase-9 activity, and expression of selected genes related to apoptosis.
Results—PL cows had significantly higher total lymphocyte counts and significantly lower proportions of T-lymphocyte populations than did BLV-negative and aleukemic cows. Both groups of BLV-infected cows had significantly higher proportions of B cells and major histocompatibility complex II–expressing cells than did BLV-negative cows. Proliferation with concanavalin A was significantly lower for PL cows, compared with proliferation for BLV-negative cows. Pokeweed mitogen–induced proliferation was significantly higher for aleukemic and PL cows than for BLV-negative cows. Gene expression of apoptosis-inhibitory proteins BCL2 and BCL2L1 was significantly higher for aleukemic cows and expression of BCL2 was significantly higher for PL cows than for BLV-negative cows.
Conclusions and Clinical Relevance—Cattle infected with BLV had marked changes in PBMC populations accompanied by alterations in proliferation and apoptosis mechanisms. Because the relative distribution and function of lymphocyte populations are critical for immune competence, additional studies are needed to investigate the ability of BLV-infected cattle to respond to infectious challenge.
Summary
Cytologic and bacteriologic responses, and changes in cytokine activity were evaluated in secretions of Staphylococcus aureus-infected mammary glands after treatment of heifers with recombinant bovine interferon gamma (rbIFNγ) or interleukin 2 (rbIL-2). Two groups of 4 heifers each, experimentally infected with 107 colony-forming units (cfu) of S aureus, were injected in 2 quarters via the teat canal, with 105 U of rbIFNγ (trial 1) or 7.5 × 105 U of rbIL-2 (trial 2) 2 weeks after experimentally induced infection; control quarters received phosphate-buffered saline solution. Mammary secretion samples were taken on days 0, 1, 2, 3, 4, 7, and 14 after cytokine infusion. Secretions were diluted 1:10 and used to perform somatic cell counts (scc), differential cell counts, and cfu enumerations, and to determine the number of leukocytes expressing major histocompatibility complex class-II (mhc II) antigens. In addition, mammary secretion samples taken on days 0, 1, and 2 were processed to obtain skimmed milk for evaluation of rbIFNγ- and rbIL-2-like activities. Treatment with rbIFNγ did not influence scc, or differential or bacteria counts, or the number of leukocytes expressing mhc II antigens. However, rbIL-2 stimulated leukocytosis, which may have reduced bacteria counts early in the trial; treatment with this cytokine also increased the neutrophil, macrophage, lymphocyte, and eosinophil counts in secretions. Similarly, numbers of mhc II-positive leukocytes were greater in rbIL-2-treated quarters vs controls. Compared with day 0, IFNγ-like activity was increased on only day 1 in both trials. Interleukin-2-like activity was not influenced in the rbIFNγ trial, but was increased on days 1 and 2 in the rbIL-2 trials. Results indicated that neither cytokine may have had a major influence on the course of established S aureus infections. However, the increased scc in rbIL-2-treated quarters may have accounted for the reduction in cfu throughout the trial after treatment with this cytokine. Greatest cytokine-like activity was observed on day 1; however, the consequences of cytokine activity, such as the sustained eosinophilia after rbIL-2 treatment, were detected over the 14-day trial period, indicating possible prolonged action.
Abstract
The subclinical impact of bovine leukemia virus (BLV) on the sustainability of the US dairy industry is only now being fully recognized. Findings of recent longitudinal studies conducted in Michigan dairy herds were consistent with the results of previous studies in showing that within-herd prevalence of BLV–infected cattle was negatively associated with milk production and cow longevity. Risk factors relating to routes of hematogenous transmission such as the use of shared hypodermic needles, shared reproductive examination sleeves, and natural breeding were associated with BLV within-herd prevalence. Few US dairy producers know the prevalence of BLV-infected cattle in their herds or are aware of the insidious economic impact of BLV or the options for BLV control. As an increasing number of countries eradicate BLV from their cattle populations, restrictions on the movement of US cattle and cattle products will likely increase. Veterinarians should be aware of recent developments for screening serum and milk samples for antibodies against BLV and the results of research regarding the economic impact of BLV so they can advise their dairy clients of available alternatives for monitoring and controlling BLV infection.
Abstract
Objective—To determine the effects of 2 weeks of intense exercise on expression of markers of pulmonary venous remodeling in the caudodorsal and cranioventral regions of the lungs of horses.
Animals—6 horses.
Procedures—Tissue samples of the caudodorsal and cranioventral regions of lungs were obtained before and after conditioning and 2 weeks of intense exercise. Pulmonary veins were isolated, and a quantitative real-time PCR assay was used to determine mRNA expression of matrix metalloproteinase-2 and −9, tissue inhibitor of metalloproteinase-1 and −2, collagen type I, tenascin-C, endothelin-1, platelet-derived growth factor, transforming growth factor (TGF)-β, and vascular endothelial growth factor (VEGF). Protein expression of collagen (via morphometric analysis) and tenascin-C, TGF-β, and VEGF (via immunohistochemistry) was determined.
Results—Exercise-induced pulmonary hemorrhage was detected in 2 horses after exercise. The mRNA expression of matrix metalloproteinase-2 and −9, tissue inhibitor of metalloproteinase-2, TGF-β, and VEGF was significantly lower in pulmonary veins obtained after exercise versus those obtained before exercise for both the caudodorsal and cranioventral regions of the lungs. Collagen content was significantly higher in tissue samples obtained from the caudodorsal regions of the lungs versus content in samples obtained from the cranioventral regions of the lungs both before and after exercise. Exercise did not alter protein expression of tenascin-C, TGF-β, or VEGF.
Conclusions and Clinical Relevance—Results of this study indicated 2 weeks of intense exercise did not alter expression of marker genes in a manner expected to favor venous remodeling. Pulmonary venous remodeling is complex, and > 2 weeks of intense exercise may be required to induce such remodeling.
