12th Ljudevit Jurak International Symposium on
Comparative Pathology
Zagreb
June 1-2, 2001
 

ABSTRACT
CHANGES IN POPULATION AND SUBPOPULATION OF T LYMPHOCYTES IN THE INTESTINE OF PIGS INFECTED WITH HOG CHOLERA VIRUS (HCV) 
P.J. Sanchez-Cordón, S. Romanini, E. Ruiz-Villamor*, F.J. Salguero, L. Carrasco, J.C. Gómez-Villamandos
Department of Veterinary Pathology, Veterinary Faculty, University of Córdoba,Cordoba, Spain
*Laboratorio Central de Veterinaria, Santa Fe, Granada, Spain
AIM OF THE STUDY: To study the lesions and their relationship with the presence of viral antigen in the intestine of pigs infected with HCV, as well as the evolution and alteration in the population and subpopulation of T lymphocytes in the intestine during the disease.
MATERIALS & METHODS: 44 pigs were inoculated by the intramuscular route with HCV and killed  2 days post-inoculation (dpi) to 23 dpi. 4 animals were used as uninfected controls. Samples of different intestinal areas were fixed in formalin, Bouin’s solution and glutaraldehyde (2’5%) and routinely processed for a histopathological and ultrastructural study. Immunochemical study with antibodies CD3, CD4 and CD8 (against T lymphocytes) and WH303 (against gp55 HCV) was developed according to ABC technique. Tunel technique and an electron microscope were used to study cellular apoptosis.
RESULTS: The histopathological study showed lymphoid depletion in Peyer’s patch from 5 dpi until the end of the experience. In the lymphoid follicles, apoptosis of lymphocytes were obvious from 5 to 14 dpi, with a significant decrease  at 14 dpi onwards. Dilated crypts were observed between 11 to 15 dpi. Immunopositive cells against gp-55 were mainly monocytes, macrophages, lymphocytes and fibroblasts. The viral infection
was confirmed by ultrastructural study. Moreover, from 2 dpi monocyte-macrophage cells showed subcellular changes indicative of secretory and phagocytic activation. The distribution of T lymphocyte was similar in  different intestinal areas during the disease. The number of immunostained cells to CD3, CD4 and CD8 was progressively increased until the end of the experience. The most significant result was the increased number of lymphocytes inside lymphoid follicles, together with the apoptosis of the T cells.
CONCLUSION: The depletion of intestinal lymphoid follicles was related to apoptosis, which coincided with the presence of viral infection in intrafollicular macrophages and a small number of lymphocytes as well as an increased number of intrafollicular T lymphocytes. The depletion of T lymphocytes in the middle and at the end of the disease was related with apoptosis too.

This paper has been supported by a grant from DGESIC (PB98-1033)

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