A “possible” involvement of TNF-alpha in apoptosis induction in peripheral blood lymphocytes of cats with feline infectious peritonitis

• Published in: Veterinary microbiology Vol. 119; no. 2; pp. 121 - 131
• Main Authors: Takano, Tomomi, Hohdatsu, Tsutomu, Hashida, Yoshikiyo, Kaneko, Yasuhiro, Tanabe, Maki, Koyama, Hiroyuki
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 31.01.2007; Elsevier Science
• Subjects: Animals; Apoptosis; Apoptosis - immunology; Biological and medical sciences; Cats; CD8 + cell; CD8-Positive T-Lymphocytes - cytology; CD8-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - virology; Cells, Cultured; Feline Infectious Peritonitis - immunology; Feline Infectious Peritonitis - virology; FIP; Fundamental and applied biological sciences. Psychology; In Situ Nick-End Labeling - veterinary; Leukocytes, Mononuclear - cytology; Leukocytes, Mononuclear - immunology; Leukocytes, Mononuclear - virology; Lymphocyte Count - veterinary; Lymphopenia; Macrophages; Microbiology; Receptors, Tumor Necrosis Factor - immunology; Receptors, Tumor Necrosis Factor - physiology; Receptors, Tumor Necrosis Factor, Type I - immunology; Receptors, Tumor Necrosis Factor, Type I - physiology; Receptors, Tumor Necrosis Factor, Type II - immunology; Receptors, Tumor Necrosis Factor, Type II - physiology; RNA, Messenger - metabolism; Specific Pathogen-Free Organisms; TNF-alpha; TNF-receptor; Tumor Necrosis Factor-alpha - genetics; Tumor Necrosis Factor-alpha - physiology; CD8 + cell; TNF-receptor; Lymphopenia; FIP; TNF-alpha; Apoptosis; Feline infectious peritonitis; Leukopenia; Microbiology; Cytokine; Peripheral blood circulation; CD8+ cell; Hemopathy; Infection; Tumor necrosis factor; Cell death; Viral disease; Veterinary; Lymphocyte; Lymphocytopenia
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2006.08.033

Feline infectious peritonitis (FIP) cats show a decrease in peripheral blood lymphocyte counts, and a particularly marked decrease in T cells including CD4 + and CD8 + cells. In this study, we showed that lymphopenia observed in FIP cats was due to apoptosis, and that the ascitic fluid, plasma, and culture supernatant of peritoneal exudate cells (adherent cells with macrophage morphology, or PEC) from FIP cats readily induced apoptosis in specific pathogen-free cat peripheral blood mononuclear cells, particularly CD8 + cells. In addition, TNF-alpha released from macrophages and TNF-receptor (TNFR) 1 and TNFR2 mRNA expression in lymphocytes were closely involved in this apoptosis induction. In particular, in CD8 + cells cultured in the presence of the PEC culture supernatant, the expression levels of TNFR1 and TNFR2 mRNA were increased, indicating that CD8 + cells are more susceptible to apoptosis induction by TNF-alpha than other lymphocyte subsets, particularly B cells (CD21 + cells). The results of this study suggest that TNF-alpha, produced by virus-infected macrophages, is responsible for induction of apoptosis in uninfected T cells, primarily CD8 + T cells.