MORPHOLOGICAL STUDY ON THE PENILE SKIN OF BUFFALO AND DOG WITH SPECIAL EFERENCE TO THE CELLS OF THE IMMUNE SYSTEM AND THEIR RELATION TO KERATINOCYTES

Materials were collected from 8 males of both buffaloes and dogs. There were no, hair follicles, sweat glands, sebaceous glands and pigment granules in the penile skin of buffalo and dog. The most prominent cells of the immune system in the penile skin of buffalo were plasma cells,
Assiut Vet. Med. J. Vol. 41 No. 82, July 1999.
macrophages, lymphocytes and mast cells while in dog these cells were lymphocytes and mast cells. Aggregations of plasma cells appeared in the narrow long dermal papillae of the penile skin of buffalo which extending toward the epidermis and sometimes become near the epidermal surface. Plasma cells could be demonstrated singly or in groups in small lacunae between the keratinocytes. The plasma cells inside the lacunae developed from cell proliferation and maturation of migranting B-lymphocytes. Macrophages associated the aggregations of plasma cells. Macrophages sometimes partially embedded toward the keratinocytes; this may indicate their active movement. By this movement and the action of wear and tear forces on the epithelium, the macrophages are deviated with compensatory keratinocytes to be seen even in lacunae between the keratinocytes. Lymphoid follicles were few in the penile skin of buffalo but were frequent in dog. The lymphoid follicles form dome - shape with the epidermis of the penile skin of dog. The epidermis was so thin at the central free part of the dome and its innermost keratinocytes were interrupted due to the infiltration by many lymphocytes; moreover the keratinocytes of the central free point of the dome sometimes appeared so loose. All these features enable lymphocytes to face down the foreign antigen on the external surface of epidermis. The germinal center of lymphoid follicles in dog was not in the center. The distribution of mast cells was similar in both buffalo and dog. The present study suggested that there is a functional relationship for both plasma cells and macrophages with keratinocytes and this relationship is species dependent.