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Antigen recognition on Anaplasma marginale and bovine erythrocytes: an electron microscopy study
S Giardina1, P M Aso, A Bretaña
1Universidad Simon Bolivar, Depto. Biología Celular, Caracas, Venezuela.
Insights
Anaplasma marginale infection in cattle alters red blood cell membranes, potentially triggering an autoimmune response. Bovine immune sera also recognize parasite components, indicating a dual immune recognition during infection.
Area of Science:
- Veterinary Immunology
- Parasitology
- Cell Biology
Background:
- Anaplasma marginale is a significant cattle pathogen causing economic losses.
- The immune response to A. marginale, particularly concerning host cell interactions, requires further elucidation.
Purpose of the Study:
- To investigate the reactivity of bovine sera from A. marginale-infected cattle against host red blood cells and the parasite itself.
- To explore potential autoimmune mechanisms and host immune recognition of A. marginale.
Main Methods:
- Electron immunomicroscopy was employed to analyze serum reactivity.
- Sera from infected and control cattle were incubated with red blood cells and purified A. marginale bodies.
Main Results:
- Immune sera from infected cattle recognized epitopes on both bovine red blood cell membranes and A. marginale bodies.
- Sera from non-infected cattle showed no such reactivity.
- A. marginale infection appears to induce structural/biochemical changes in red blood cell membranes.
Conclusions:
- A. marginale infection may induce autoimmune responses against bovine red blood cells, potentially leading to erythrophagocytosis.
- The bovine immune system mounts a response against parasite-specific epitopes during infection.
Abstract:
The reactivity of sera from Anaplasma marginale-infected bovine with red blood cells and with purified anaplasma bodies was analyzed by electron immunomicroscopy. Red blood cells from non-infected and from anaplasma-infected cows and A. marginale bodies separated from parasitized erythrocytes, were incubated with control, pre-immune and immune sera followed by anti-bovine IgG-Peroxidase. Immune sera from cows infected with the venezuelan and Florida isolate reacted with red blood cell membranes from normal and infected bovines, while sera from non-infected cows did not. The immune sera also recognized epitopes localized on the cell wall, membrane and on unidentified intracellular structures of the purified anaplasma bodies. Thus, we propose that A. marginale infection may cause structural and biochemical modifications of the plasma membrane of the bovine red blood cells during its intraerythrocytic cycle. This in turn could elicit an autoimmune type of response against its own cells that would stimulate erythrophagocitosis. The strong reactivity of the immune sera with the Anaplasma bodies suggests that the bovine immune system also recognizes epitopes located on the parasite.
