کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8991133 | 1555809 | 2005 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Immune response to Neospora caninum in naturally infected heifers and heifers vaccinated with inactivated antigen during the second trimester of gestation
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موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
علوم دامی و جانورشناسی
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چکیده انگلیسی
The objective of this study was to compare the immune response to Neospora caninum in naturally infected heifers and heifers inoculated with a killed whole N. caninum tachyzoite preparation during the second trimester of gestation. Nine Holstein heifers were used in this study; three naturally infected heifers were born from seropositive dams, and six seronegative heifers were born from seronegative dams. Four seronegative heifers were subcutaneously vaccinated with a killed whole N. caninum tachyzoite preparation at weeks 13, 15 and 17 of gestation. A killed whole N. caninum tachyzoite preparation containing 45 mg of protein/5 ml dose was formulated with 70% of mineral oil adjuvant (13% consisting of Arlacel C, 85% Marcol 52 and 2% Tween-80). Similarly, two seronegative heifers (negative controls) were inoculated with mock-infected bovine monocytes in oil adjuvant. Humoral immune responses were tested by using an indirect fluorescent antibody test (IFAT) and an indirect enzyme-linked immunosorbent assay (ELISA) for detecting isotype specific antibodies. Cellular immune responses were assessed by lymphocyte proliferation test (LPT) and IFN-γ production. N. caninum-specific antibody responses increased in immunized cattle by week 15 of gestation (mean reciprocal antibody titers 450 ± 252), peaked at week 23 (mean 16,000 ± 6400). Maximum antibody response in naturally infected heifers was observed at week 19 of gestation (mean: 3467 ± 2810). Mean serum IFAT titers were significantly higher in immunized heifers compared with those in naturally infected heifers from weeks 17 to 25 (P < 0.05). Analysis of isotype specific antibodies in naturally infected heifers revealed a predominant IgG1 response in one heifer and a predominant IgG2 response in the other two. Similar titers of IgG1 and IgG2 occurred in immunized heifers. Control heifers remained seronegative throughout the study by IFAT and ELISA. Significant antigen-specific proliferation responses were only detected in naturally infected heifers in week 19 of gestation. Peripheral mononuclear blood cells (PMBC) from immunized animals produced IFN-γ in similar concentrations to those of infected animals (P > 0.05). No abortion was seen in any experimental group; however, one calf from a vaccinated heifer died due to dystocia. All calves from vaccinated and control heifers were seronegative by IFAT at 6 months of age; in contrast, calves born from naturally infected heifers remained seropositive with titers â¥200. Killed vaccine induced similar immune responses to those found in chronically, naturally infected cattle which did not abort; however, different immune pathways may be followed in vaccinated and natural infected heifers with differences in degree of protective immunity.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Veterinary Parasitology - Volume 130, Issues 1â2, 10 June 2005, Pages 29-39
Journal: Veterinary Parasitology - Volume 130, Issues 1â2, 10 June 2005, Pages 29-39
نویسندگان
D.P. Moore, M.R. Leunda, P.I. Zamorano, A.C. Odeón, S.A. Romera, A. Cano, G. de Yaniz, M.C. Venturini, C.M. Campero,