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Crossbred cattle are more prone to mastitis in comparison to indigenous cattle. Toll-like receptor 4 (TLR4) recognizes pathogen ligands, for example, lipopolysaccharide (LPS) endotoxin fromEscherichia coliand mediates signaling to initiate innate and adaptive immune responses. Mutations in TLR4 can compromise the host immune response to certain pathogens, so it may be a potential candidate for marker assisted selection to enhance mastitis resistance in dairy cattle. Hence, in this study role of bovine TLR4 gene in mastitis resistance was investigated by association as well as expression profiling analysis in crossbred cattle. The animals were divided into mastitis affected and unaffected groups on the basis of history of animals and California Mastitis Test (CMT). PCR-SSCP and Sequence analysis revealed three genotypes of coreceptor binding region 1 (CRBR1) fragment of TLR4 gene namely AA, AB, and BB in both groups of cattle. The logistic regression model did not show any significant effect of these genotypes on the occurrence of clinical mastitis. Moreover, in vitro challenge of peripheral blood mononuclear cells (PBMCs) with LPS failed to show any association of the genotypes with TLR4 gene expression. In a nutshell, in the present study enough evidence was not found for association of the SNP variants of CRBR1 fragment of TLR4 gene with mastitis susceptibility in crossbred cattle. [ABSTRACT FROM PUBLISHER]

Bovine tropical theileriosis is an important haemoprotozoan disease associated with high rates of morbidity and mortality particularly in exotic and crossbred cattle. It is one of the major constraints of the livestock development programmes in India and Southeast Asia. Indigenous cattle ( Bos indicus ) are reported to be comparatively less affected than exotic and crossbred cattle. However, genetic basis of resistance to tropical theileriosis in indigenous cattle is not well documented. Recent studies incited an idea that differentially expressed genes in exotic and indigenous cattle play significant role in breed specific resistance to tropical theileriosis. The present study was designed to determine the global gene expression profile in peripheral blood mononuclear cells derived from indigenous (Tharparkar) and cross-bred cattle following in vitro infection of T . annulata (Parbhani strain). Two separate microarray experiments were carried out each for cross-bred and Tharparkar cattle. The cross-bred cattle showed 1082 differentially expressed genes (DEGs). Out of total DEGs, 597 genes were down-regulated and 485 were up-regulated. Their fold change varied from 2283.93 to − 4816.02. Tharparkar cattle showed 875 differentially expressed genes including 451 down-regulated and 424 up-regulated. The fold change varied from 94.93 to − 19.20. A subset of genes was validated by qRT-PCR and results were correlated well with microarray data indicating that microarray results provided an accurate report of transcript level. Functional annotation study of DEGs confirmed their involvement in various pathways including response to oxidative stress, immune system regulation, cell proliferation, cytoskeletal changes, kinases activity and apoptosis. Gene network analysis of these DEGs plays an important role to understand the interaction among genes. It is therefore, hypothesized that the different susceptibility to tropical theileriosis exhibited by indigenous and crossbred cattle is due to breed-specific differences in the dealing of infected cells with other immune cells, which ultimately influence the immune response responded against T . annulata infection. [ABSTRACT FROM AUTHOR]