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Bovine venereal vibriosis: activity of inflammatory cells in protective immunity
Abstract:
The capability of bovine polymorphonuclear (PMN) and mononuclear phagocytes to kill Campylobacter (Vibrio) fetus venerealis was tested under various conditions in order to judge their roles in protective immunity. Bovine PMN killed C fetus in the presence of immunoglobulin G (IgG) but not immunoglobulin A (IgA) antibodies. Some phagocytosis occurred in the absence of antibody in glass-adherent cultures, but not in suspension cultures--indicating that surface phagocytosis by the neutrophils normally present during estrus could account for natural protection at this time. Mononuclear phagocytes also killed C fetus in the presence of opsonins, making this a likely factor in protection during the later stages of inflammation when mononuclear cells predominate. The presence of numerous lymphocytes in this mononuclear infiltration and the capability of C fetus antigens to induce delayed hypersensitivity (DH) are consistent with the possibility that cell-mediated immunity (CMI) also may be involved in protective immunity.
Insights
Bovine immune cells, including polymorphonuclear (PMN) and mononuclear phagocytes, demonstrate varying capabilities in eliminating Campylobacter fetus. Antibody presence and cell adherence influence phagocytosis, suggesting roles for both innate and adaptive immunity in bovine protection against C. fetus.
Area of Science:
- Immunology
- Veterinary Microbiology
- Bovine Infectious Diseases
Background:
- Campylobacter fetus venerealis is a significant pathogen in cattle, causing reproductive diseases.
- Understanding the bovine immune response is crucial for developing effective control strategies.
- Polymorphonuclear (PMN) and mononuclear phagocytes are key components of the innate immune system.
Purpose of the Study:
- To evaluate the killing capacity of bovine PMN and mononuclear phagocytes against Campylobacter fetus.
- To determine the influence of antibodies (IgG, IgA) and culture conditions on phagocytosis.
- To assess the potential roles of innate and cell-mediated immunity in protective immunity against C. fetus.
Main Methods:
- In vitro assays were used to test the phagocytic and bactericidal activity of bovine PMN and mononuclear phagocytes.
- Experiments were conducted under various conditions, including the presence or absence of specific antibodies (IgG, IgA) and different culture formats (adherent vs. suspension).
- The induction of delayed hypersensitivity (DH) by C. fetus antigens was also investigated.
Main Results:
- Bovine PMN effectively killed C. fetus in the presence of IgG antibodies but not IgA.
- Phagocytosis by neutrophils occurred in adherent cultures (mimicking estrus conditions) but not in suspension, suggesting a role for surface phagocytosis in natural protection.
- Mononuclear phagocytes killed C. fetus when opsonized, indicating their importance in later inflammatory stages and potentially in cell-mediated immunity (CMI) due to lymphocyte presence and DH induction.
Conclusions:
- Both PMN and mononuclear phagocytes contribute to the elimination of C. fetus in cattle.
- The effectiveness of these cells is modulated by antibody presence and adherence properties.
- Natural protection may involve surface phagocytosis by neutrophils during estrus, while mononuclear phagocytes and CMI are likely important in later immune responses.