MHC-DQB1 Variation and Its Association with Resistance or Susceptibility to Cystic Echinococcosis in Chinese Merino Sheep

Abstract

Cystic echinococcosis (CE), one of the world’s most geographically widespread diseases, still represents a considerable economic and public health significance, although a variety of methods has been used to control the disease. It has been demonstrated that genetic factors, especially variations in MHC loci, can influence the outcome of CE infection in the human population. The study described here was designed to determine whether variation in MHC-DQB1 was associated with susceptibility or resistance to CE in sheep. If so, it would lay a theoretical foundation for breeding disease resistance sheep in future. This study was carried out on 204 Chinese Merino sheep, including 101 CE sheep and 103 healthy controls. The polymorphism of MHC-DQB1 exon 2 was detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, and x2 test was used to compare genotype frequencies between CE sheep and healthy controls. A total of 22 alleles and 42 genotypes were identified in DQB1 exon 2 in Chinese Merino sheep. In addition, x2 test showed that frequencies of DQB1-TaqIaa and DQB1-HaeIIInn genotypes were significantly higher in the healthy group (82.5% and 57.3%, respectively) than that in the CE group (57.4% and 28.9%, respectively) (both p values = 0, OR = 0.286, 0.303, respectively), suggesting that these genotypes appeared to be associated with resistance to CE. Whereas, frequencies of DQB1-TaqIab and DQB1-HaeIIImn genotypes were significantly higher in the CE group (36.9% and 32.0%, respectively), as compared with the healthy group (16.5% and 11.15%, respectively) (p = 0.001, 0.001 and OR = 2.963, 3.629, respectively), indicating that these genotypes might be associated with susceptibility to CE. It is concluded that the genetic polymorphism within MHC-DQB1 might influence immune responses to pathogens, thus leading to the development of CE or protection against CE in Chinese Merino sheep, which would pave the way for breeding disease resistance sheep in future.

Intestinal transcriptomes in Kazakh sheep with different haplotypes after experimentalEchinococcus granulosusinfection

“…Previously, we carried out a series of studies to research the relationship between MHC polymorphisms and resistance or susceptibility to CE in native Chinese sheep, including Chinese Merino [ 21 ], Duolang [ 28 ], and Kazakh sheep [ 29 ]. Our previous studies indicated that in Kazakh sheep, when exposed to the same number of parasites, the rate of E. granulosus infection in the internal organs of sheep with haplotype MHC Mva I bc- Sac II ab- Hin 1I ab haplotype was significantly lower than in sheep without this haplotype.…”

“…It has been found that when sheep were infected with oncospheres (larvae of E. granulosus ), the small intestine tissue was the first mucosal immune barrier that must be passed through, where various antibodies, cytokines, and other immune molecules are expressed in response to exogenous stimuli [ 12 ]. These molecules could be involved in stopping larval growth of E. granulosus at the very first stages [ 11 , 21 , 28 , 29 ]. Hence, we were interested to see the molecular mechanisms of CE resistance in Kazakh sheep with the resistant haplotype, at the very first stage of infection.…”