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Effect of CD4+ T lymphocyte depletion on resistance of Gulf Coast Native lambs to Haemonchus contortus infection.
- Source :
-
Veterinary parasitology [Vet Parasitol] 2006 Jun 15; Vol. 138 (3-4), pp. 240-6. Date of Electronic Publication: 2006 Mar 03. - Publication Year :
- 2006
-
Abstract
- It has been reported that CD4(+) T lymphocytes are important in acquired immunity to gastrointestinal nematode infection. Whether these lymphocytes are also involved in the immune response of naturally resistant Gulf Coast Native (GCN) sheep to Haemonchus contortus infection remains to be defined. The objective of this study was to determine the role of CD4(+) T lymphocytes in this resistance. Ten GCN lambs were randomly assigned to a control (n=5) or a treatment (n=5) group. The treatment consisted of a series of IV injections with mouse anti-ovine CD4(+) T lymphocyte monoclonal antibodies for a period of 3 weeks. After the second treatment, all lambs were experimentally infected with 10,000 H. contortus infective larvae by oral inoculation. All lambs were monitored for fecal egg counts, blood packed cell volumes, white blood cell differential counts and serum antibody responses on a weekly basis. Fluorescence-activated cell sorter (FACS) analysis was done biweekly to enumerate CD4(+) T lymphocytes in peripheral blood. Necropsies were performed at the end of the study and 10% of the contents of the gastrointestinal tract were preserved for nematode enumeration and identification. Also at necropsy, mesenteric lymph nodes were extracted and FACS analysis was run on lymphoid cells. Mean fecal egg counts on day 21 and 28 post-infection and nematode counts at necropsy of the treated group were significantly (p<0.05) higher than that of the control group. Percent CD4(+) T lymphocytes in peripheral blood was significantly (p<0.05) lower in the treatment group than in the control group from day 9 to the end of the study. No differences were found in blood packed cell volumes, white blood cell differential counts, antibody titer or lymph node CD4(+) lymphocytes between groups. Lambs depleted of their CD4(+) T lymphocytes were more susceptible to H. contortus infection than undepleted lambs. The results of this study suggest that CD4(+) T lymphocytes are associated with the natural resistance of GCN sheep to H. contortus infection.
- Subjects :
- Abomasum parasitology
Animals
Antibodies, Helminth administration & dosage
Antibodies, Helminth immunology
CD4-Positive T-Lymphocytes drug effects
Feces parasitology
Flow Cytometry veterinary
Haemonchiasis immunology
Haemonchiasis parasitology
Hematocrit veterinary
Immunity, Innate immunology
Leukocyte Count veterinary
Lymph Nodes immunology
Lymphocyte Activation
Mice
Mitogens pharmacology
Parasite Egg Count veterinary
Random Allocation
Sheep
Sheep Diseases parasitology
CD4-Positive T-Lymphocytes immunology
Haemonchiasis veterinary
Haemonchus immunology
Lymphocyte Depletion veterinary
Sheep Diseases immunology
Subjects
Details
- Language :
- English
- ISSN :
- 0304-4017
- Volume :
- 138
- Issue :
- 3-4
- Database :
- MEDLINE
- Journal :
- Veterinary parasitology
- Publication Type :
- Academic Journal
- Accession number :
- 16516389
- Full Text :
- https://doi.org/10.1016/j.vetpar.2005.12.026