IMPACT OF CXC SIGNALING NETWORK GENE POLYMORPHISMS ON RESISTANCE/SUSCEPTIBILITY TO BOVINE LEUKEMIA VIRUS (BLV)

Numerous findings confirm the association between gene polymorphism and the development of many virus-induced disease investigate genotype and haplotype distributions of some genes of chemokine network (CXCL (GROX and GRO3) /CXCR2 (IL8)) in populations of Black- and White x Holstein cross-breed cattle and to estimate their impact on resistance/susceptibility to BLV infection. collected from Black and White cross breed cattle at two farms, Tulinskoye (with low prevalence BLV infection) and Kremlevskoe (with high prevalence BLV infection) in Novosibirsk region. The DNA blood extraction was performed using the standard technique. The DNA amplification was carried out under standard conditions in the of 15–50 µl using DNA-polymerase. Locus-specific PCR for genotyping performed

Resistance/susceptibility to tumor-associated infectious diseases depends on immune gene polymorphism, in particular on the genes of chemokine network, since chemokines are key messengers of intercellular The aim of the present study was to investigate genotype and haplotype distributions of some genes of chemokine network (CXCL (GROX and GRO3) /CXCR2 (IL8)) in populations of Black-and White x Holstein cross-breed cattle and to estimate their impact on resistance/susceptibility to BLV infection.
The blood was collected from Black and White Holstein (n=340) cross breed cattle at two farms, Tulinskoye (with low prevalence BLV infection) and Kremlevskoe (with high prevalence BLV infection) in Novosibirsk region. The DNA blood extraction was performed using the standard technique. The DNA amplification was carried out under standard conditions in the volume of 15-50 µl using DNA-polymerase. Locus-specific PCR for genotyping was performed as it described previously (Heaton M. P. et al. 1999) with some modifications. For RFLP-analysis of signaling network genes CXCL (GROX, GRO3 and CXCR2 (IL8RB)), we used the following restriction endonucleases: Commercial diagnostic test based on agar gel immunodiffusion (AGID) was used to detect BLV. Additional PCR analysis of BLV infection was described previously (Licursi M. et al.2002). The following groups of animals have been formed depending on their BLV-status: 1) AGID-PCR-: healthy animals (control group); 2) BLV-infected (AGID+ PCR-) 3) animals with leucosis (AGID+, PCR+). Statistical processing was performed using SPSS software.
The genotype study of cattle with different BLV status Some of previously identified SNP-markers of cytokine network genes (Heaton M. P. et al. 1999) were chosen for analysis: chemokine GRO family (GROX and GRO3), their common receptor IL8RB. These molecules are believed to be involved in immune protection and tumor angiogenesis. The PCR-RFLP genotyping results for animal groups with different BLV status are presented in Table 1.  Table 1 clearly shows that genotype distribution patterns have locus-and SNP-specificity. Simultaneous genotype frequency comparison revealed the significance of the most of analyzed SNPs (gray line), with the exception of AH5-1, 2, and AH6-1, To better understand the role of SNP in leukemia development we have performed a pairwise comparison of animal groups to look at polymorphism patterns in different BLV statuses (Table 2). Table shows that differences in AH3 GRO2 (X) SNP marker distribution patterns (gray line) were most significant between animals with leucosis (AGID+PCR+) and animals BLV infected animals (virus carries (AGID+ PCR-). Significant differences were also identified for distribution of AH5-3 GRO3 and AH6-2 IL8R SNP markers for BLV infected animals (AGID+PCR-) vs healthy animals (AGID+PCR-). Comparison of healthy animals and animals with leucosis («disease-susceptible") showed significant differences in AH6-3 IL8RB marker distribution. So, these are the markers of infection predisposition and disease progression.
Thus, there are clear evidence that suggest various chemokine network genes and their allelotypes are involved in different stages of virus leukemia.
The mechanisms of the effect of allelic variability of chemokine and their receptors genes on susceptibility to bovine lymphocytosis require further study.