The role of pattern-recognizing receptors of innate immunity cells in the pathogenesis of cattle diseases (review)

The problem of increasing the natural resistance of highly productive cattle environment in industrial conditions is becoming increasingly relevant. Infections of the mammary glands, reproductive system, and viral diseases of cattle entail economic spends associated with a decrease in milk production, treatment costs and culling of weak animals. The key to maintaining homeostasis in the body and preserving the health of the animal is the timely recognition of pathogens by cells of the innate immune system. Currently, many molecular mechanisms of the immune cell activation have been established by human and mouse models; the role of pattern recognition receptors (PRRs) (J. Xu et al., 2011; I.F. Moretti et al., 2018), adapter proteins and transcription factors in the formation of an immune response has been shown (T. Kawai et al., 2008), which includes not only the recognition and removal of foreign pathogens, but and elimination of damaged cells of one’s own body (O. Takeuchi et al., 2010; N. Kano et al., 2022). This review present modern data on the role of PRRs in recognizing pathogens and activating cells of the innate immune system in cattle: the main immunogenic structures (PAMPs and DAMPs) that affect the cells of the innate immune system in cattle are described, information on the structure and functions of the main groups of PRRs is collected , including Toll-like (TLR), NOD-like (NLR), C-type lectin-like receptors (CLR) and RIG1-like (RLR) receptors, the structural features of these receptors in cattle are shown (Z. Sladek et al., 2009; S.K. Mishra et al., 2019). In cattle, 10 functional TLRs (TLR1 to TLR10) have been identified and mapped, each recognizing specific molecular patterns associated with pathogens (M. Maurić Maljković et al., 2023), 32 types of CLR molecules, most of which can be identified as orthologs of human and mouse proteins (A. Holder et al., 2023). The NOD-like receptor family consists of 4 subfamilies. NOD1 and NOD2 play an autoregulatory role (N. Inohara et al., 1999) and are involved in signal transduction to adaptor proteins (G. Magnuson et al., 2010). RLRs include three receptors: RIG-I, MDA5 and LGP2 (K. Wicherska-Pawłowska et al., 2021), RIG-I-like receptors are cytoplasmic nucleic acid receptors for virion RNA. Their role in the induction of the innate immune response during protection against rotavirus infecti on (P.S. Paul et al., 1993; K. de Verdier Klingenberg et al., 1998) and recognition of bovine diarrhea virus has been established (Y. Ma et al., 2022).To better understand the role of PRRs in cell activation, the pathways of intracellular signal transmission from receptors upon their activation are depicted (J. Napetschnig et al., 2013; T. Kawai et al., 2008). The importance of PRR in the formation of inflammatory diseases in cattle has been shown (M. Maurić Maljković et al., 2023). Special attention is paid to the influence of PRR gene polymorphism on cattle resistance to infectious diseases such as mastitis (A.Q. de Mesquita et al., 2012), tuberculosis (A. Bhaladhare et al., 2016), paratuberculosis (R. Mucha et al., 2009; J.B. Okuni et al., 2021) and other diseases (M. Bjelka et al., 2020). Identification of PRR single nucleotide polymorphisms opens up promising opportunities for marker-based selection strategies, disease risk screening and increasing the genetic resistance of dairy cattle to diseases (M. Maurić Maljković et al., 2023).