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Published on: July 11, 2015
Analysis of cellular responses to native and recombinant proteins of Cowdria ruminantium
P Totté1, D McKeever, F Jongejan
1CIRAD-EMVT, Point-à-Pitre, Gaudeloupe, French West Indies.
Insights
Cattle immune responses to Cowdria revealed that CD4+ T cells strongly recognized Cowdria lysates. Other T cell types responded to specific recombinant proteins, suggesting novel immunogenic targets beyond MAP1 and MAP2.
Area of Science:
- Veterinary Immunology
- Cellular Immunology
- Microbial Pathogenesis
Background:
- Cowdria ruminantium is an important tick-borne pathogen affecting cattle.
- Understanding the immune response to Cowdria is crucial for vaccine development.
- Previous studies identified MAP1 and MAP2 as serologically immunodominant antigens.
Purpose of the Study:
- To characterize the in vitro immune response of cattle PBMCs to Cowdria antigens.
- To identify which Cowdria components elicit T lymphocyte responses.
- To explore potential antigens for improved vaccine strategies.
Main Methods:
- Peripheral blood mononuclear cells (PBMC) were collected from cattle immunized with killed Cowdria.
- PBMCs were stimulated in vitro with recombinant MAP1, MAP1-B, MAP2, and Cowdria lysates.
- Cell proliferation and T lymphocyte subset responses (CD4+, gamma delta T cells) were analyzed.
- Short-term cell lines were generated and characterized.
Main Results:
- CD4+ T lymphocytes showed a strong proliferative response to Cowdria lysates.
- B cells and gamma delta T cells proliferated in response to recombinant proteins (MAP1, MAP1-B, MAP2).
- Cell lines generated from Cowdria lysate stimulation were predominantly CD4+ T cells.
- Cell lines generated using MAP1 were primarily gamma delta T cells and showed limited proliferation.
Conclusions:
- T lymphocytes, particularly CD4+ T cells, recognize Cowdria antigens beyond the serologically dominant MAP1 and MAP2.
- Recombinant proteins like MAP1, MAP1-B, and MAP2 elicit responses in specific T cell populations.
- These findings suggest that non-serodominant antigens may be important targets for cellular immunity and vaccine development against Cowdria.
Abstract:
The response of PBMC collected from cattle immunized with killed Cowdria to MAP1, MAP1-B, MAP2 and to a lysate of Cowdria was characterized in vitro. CD4+ T lymphocytes responded strongly to Cowdria lysates while B cells and gamma delta T cells proliferated in response to recombinant proteins. Short-term cell lines derived from PBMC using Cowdria lysates were more than 90% CD4+ and did not respond to any of the recombinant proteins. Restimulation of PBMC with MAP1, MAP1-B, and MAP2 proved difficult, and cultures usually stopped proliferating after 2 to 3 weeks. Only one cell line could be generated using MAP1 and it was composed of 85% gamma delta T cells. This study indicates that in animals immunized with killed Cowdria, proteins other than the serologically immunodominant MAP1 and MAP2 are strongly immunogenic for T lymphocytes.
