COMPARATIVE ANATOMICALLY-IMMUNOHISTOCHEMICAL CHARACTERISTICS OF SPLEEN IN REPRESENTATIVES OF BIRDS AND MAMMALS CLASSES

Abstract

Introduction. The anatomical and immunohistochemical investigates are necessary for studying the immune morphology of the spleen. They allow discovering the distribution of lymphocytes, depending on its microscopic structure. Immunohistochemical studies are used in medicine and begin to be introduced into veterinary practice for productive animals.

The aim of the study – to investigate the distribution of T- and B-lymphocytes of different clusters in the spleen, depending on the anatomical structure of the organ in the representatives of the classes Birds and Mammals.

Research Methods. The spleen was taken in clinically healthy pigeon, chicken, rabbit, and pigs in the phase of morphofunctional maturity. Then the biological materials were fixed in 10–12 % solution of neutral formalin, washed 24–48 hours, dehydrated in alcohol, poured into paraffin, and prepared histological sections on a microtome MS-2 (the thickness of 4–6 microns), stained with Hematoxylin Ehrlich and eosin. Subpopulations of lymphocytes (CD4, 8, 19, 20) were detected using murine monoclonal antibodies (DACO, Denmark). Visualization was performed using the DAKO EnVision FLEX + Detection System (DAKO, Denmark) with additional Mayer hematoxylin (DAKO, Denmark) and transfer to Eukitt (Germany).

Results and Discussion. Lymphoid nodules of mammals, in contrast to birds, have had in their structure a mantle and marginal zone and a bright centre. Lymphoid tissue of the spleen of vertebrate animals of the class Birds and Mammary was formulated with a significant number of lymphocytes with markers CD4 +, CD8 +. Such subpopulations of lymphocytes in the red pulp of the spleen of the pigeon, chicken, rabbit, and pig were placed singly and diffusely. They were often formed chains or clusters in the white pulp. Among the populations of B-lymphocytes in rabbits and pigs, lymphocytes CD19 + (83.69±8.74) and (75.14±7.13) were dominated units per unit area respectively), in birds – СD20 + (73.91±6.21) and (38.45±2.47) units per unit area respectively, in the pigeon and chicken). The immunoregulatory index was equalled 2.0 at the chicken; 1.85 in the pigeon; 1.82 in rabbit; pigs – 1.71. This indicates the development of cellular and humoral mechanisms of immunity.

Conclusions. In the process of evolutionary development, the complication and improvement of the structure of the spleen have occurred. CD4 +, CD8 + lymphocytes were dominated in the zone near the vessels and lymphoid sheaths near the vessels; and CD19 +, and CD20 + were dominated in lymphoid nodule structures.