Immunophysiological State of Dogs According to the Immunoregulatory Index of Their Blood and Spleens

In this study, the immunological characteristics of a dog's body were established, allowing for a quick reaction to any changes in the immune status and the development of an immunodeficiency state. The immunoregulatory blood index was determined to indicate the ratio of T-helpers and T-suppressors. The immunoregulatory index of the spleen was determined as the ratio of CD4+ cells to CD8+ cells in the field of view of a microscope (eyepiece 10, objective 40) after obtaining histological preparations according to generally accepted methods. It was found that the number of T-helpers decreased by 0.13 × 10¹²/L, while the number of T-suppressors increased non-significantly by 0.01 × 10¹²/L after intensive exercise during tasks. The immunoregulatory blood index of dogs was 2.1 ± 0.1 and 1.7 ± 0.13 before and after intensive exercise, respectively. Lymphocytes with markers CD4+ and CD8+ were located almost all in the white pulp; in the red pulp, they were found alone, and their share was 3.4% and 1.9%, respectively. Lymphocytes with CD4+ markers in the spleen's white pulp were mainly concentrated in lymphoid nodules (60.7%), of which 20.1% were focused on the marginal zone, and slightly less in the light center (19.4%) and the periarterial zone (18.1%). Lymphocytes with CD8+ markers in the spleen's white pulp were also mainly concentrated in lymphoid nodules, but their number was 8.1% higher (68.8%). The immunoregulatory index of the spleen is 1.9. These findings emphasize the need for the assessment of the immunoregulatory index in service dogs to prevent the development of secondary immunodeficiency and allow them to properly perform their official duties.