Comparative Transcriptome Analysis of Theileria annulata-challenged PBMCs Reveals Molecular Basis of Resistance in Vechur

Tropical theileriosis, caused by the protozoan parasite Theileriaannulata, poses a significant threat to cattle production. This study investigated the molecular basis of resistance and susceptibility to the disease by comparing the transcriptomic profiles of peripheral blood mononuclear cells from indigenous Vechur and crossbred cattle following in-vitro challenge with T. annulata. RNA sequencing analysis revealed 5910 differentially expressed genes between the two breeds. In Vechur cattle, 1858 transcripts were upregulated and 1884 were downregulated compared to crossbred cattle. Gene ontology and pathway analysis indicated that genes associated with mitosis, cell division, and cell cycle were significantly enriched, suggesting a difference in cell proliferation rates upon infection. Notably, pathways related to cancer and PI3K-Akt signaling were significantly enriched in crossbred cattle PBMCs, indicating a higher susceptibility to parasite-induced transformation. Furthermore, qRT-PCR was used to validate the expression of four key genes (IL23A, CD63, CDC42, and SERPINH1). The results showed significant upregulation of CD63 and CDC42 in infected crossbred cattle, while SERPINH1 was significantly downregulated in both infected and non-infected crossbred groups compared to Vechur cattle. These findings suggest that Vechur cattle possess enhanced immune mechanisms that control the proliferation of infected cells. This study provides valuable insights into the breed-specific molecular responses to T. annulata infection, which could aid in the development of strategies for breeding cattle with greater disease resilience.