Determination of CD Markers Profile of the Cell Line Infected by S15 Vaccine Strain of Theileria annulata Schizont Using RT-PCR Analysis

The aim of this study was to identify the cell surface cluster of differentiation (CD) markers of the cell lines infected by Theileria annulata schizont. The CD molecules are very useful for the characterization of cells and different subpopulations of leukocytes. They are usually recognized by specific antibodies using flow cytometry and immunohistochemistry. In the current study, we applied reverse transcriptase-polymerase chain reaction (RT-PCR) to define the profile of cell surface markers in a cell line infected by an attenuated S15 vaccine strain of T. annulata schizont and a new laboratory-established cell line infected by a non-attenuated form. In order to determine the specific markers that can be used for excluding the non-attenuated cell lines, the characterization of the surface proteins profile of the S15 vaccine cell line is important. The RT-PCR was carried out by specifically designed primers using a panel of seven bovine CD markers, as well as beta-actin as an internal control house-keeping gene. We showed that both of the examined cell lines had a consistent expression of CD4, CD5, CD11a, CD14, CD43, and CD45 markers. However, the specific finding in this study was the expression of B-cell markers CD79a and CD5 by the newly-transformed cell line. On the other hand, CD5 as a marker for B-cell subset was expressed by S15 vaccine strain. In conclusion, we consider CD79a surface protein as a new marker for the cell lines infected by non-attenuated T. annulata schizont, while the cell lines infected by the vaccine strain do not express this marker. In addition, the identification of CD marker expression based on the RT-PCR assay might be a suitable and appropriate alternative technique for flow cytometry.