International Journal of Molecular Veterinary Research, 2024, Vol.14, No.5, 219-226 http://animalscipublisher.com/index.php/ijmvr 220 2 Immune System in Cats 2.1 Key components of the feline immune system The feline immune system, like that of other mammals, is composed of both innate and adaptive components. The innate immune system provides the first line of defense against pathogens and includes physical barriers, phagocytic cells such as neutrophils and macrophages, and natural killer (NK) cells. These components are crucial for the initial detection and response to infections, as they recognize common structural features of pathogens (Figure 1) (De Vor et al., 2020; Capozza et al., 2021). The adaptive immune system, on the other hand, involves more specific responses mediated by T and B lymphocytes, which are responsible for immunological memory and long-lasting immunity (Medzhitov et al., 2015; Gaudino and Kumar, 2019). Figure 1 Complement and neutrophil evasion by staphylococci (Adopted from De Vor et al., 2020) Image caption: An overview of staphylococcal evasion molecules (red boxes) and their hosttargets (Adopted from De Vor et al., 2020) 2.2 Interaction between innate and adaptive immunity in cats The interaction between innate and adaptive immunity is essential for a coordinated immune response. Antigen-presenting cells (APCs), such as dendritic cells and macrophages, play a pivotal role in this interaction by presenting antigens to T cells, thereby linking the innate and adaptive immune responses (Gaudino and Kumar, 2019). This crosstalk is crucial for the activation and differentiation of T cells, which are necessary for the adaptive immune response. The innate immune system not only provides immediate defense but also influences the nature and magnitude of the adaptive immune response through cytokine production and other signaling mechanisms (Iwasaki et al., 2015; Thomas and Yang, 2016). 2.3 Immune response activation and regulation in cats The activation and regulation of the immune response in cats involve complex interactions between various immune cells and signaling molecules. Upon infection, innate immune cells recognize pathogen-associated molecular patterns (PAMPs) and initiate an inflammatory response (Capozza et al., 2021). This response is regulated by cytokines, which are produced by both innate and adaptive immune cells to coordinate the immune response (Iwasaki et al., 2015). The regulation of immune responses is critical to prevent excessive inflammation and tissue damage, and it involves feedback mechanisms that modulate the activity of immune cells (Maldonado et al., 2016). Understanding these regulatory pathways is essential for developing strategies to manage infections and immune-related diseases in cats. In summary, the feline immune system is a complex network of innate and adaptive components that work together to protect against infections. The interaction between these components is crucial for an effective immune response, and the regulation of this response is vital to maintaining immune homeostasis. 3 Subclinical Bacterial Infections: Definition and Characteristics 3.1 What defines subclinical bacterial infections? Subclinical bacterial infections are characterized by the presence of bacteria in the host without causing overt clinical symptoms. These infections can persist in a latent state, where the host's immune system is able to control
RkJQdWJsaXNoZXIy MjQ4ODYzNA==