title: Apoptotic fraction in lymphoid tissue of FIV-infected SPF cats.
abstract: In the present study the apoptotic fraction has been investigated in peripheral blood mononuclear cells (PBMCs) and in lymphoid tissue of six clinically asymptomatic serologically positive specific pathogen free (SPF) FIV-infected cats with a decline in peripheral blood CD4+ lymphocytes, compared to five FIV- SPF controls. Apoptosis in PBMCs was scored in relation to cell cycle phases judged by the integrating cytometric measure of DNA content with 3H-thymidine and 3H-leucine incorporation. Apoptosis in lymphoid tissue was revealed with the ApopTag-peroxidase kit, quantified by image analysis and expressed as apoptotic index (number of apoptosis per 100 cells). The high percentage of apoptotic death in lymphocytes from FIV+ cats was chronologically related to the entrance of cells in the S phase of the cell cycle (p < 0.0001). No difference in the apoptotic index was revealed comparing the follicular, cortical + paracortical and medullary compartments in lymph nodes of FIV+ and FIV- cats. In each group of cats a similar pattern of apoptosis expression was revealed in lymph nodes: significantly higher in follicular vs. both cortical + paracortical and medullary compartments (p < 0.001). In the thymus a significant increase in apoptotic index was revealed in the cortical compartment of the FIV+ cats compared to FIV- (p < 0.001), while in the spleen both the red and white pulp expressed a higher value in FIV+ cats compared to FIV-(p < 0.05) and the former showed a pattern of expression as follows: in the red pulp significantly higher than in the white pulp (p < 0.001). This investigation suggests that the priming signals for apoptosis in FIV infection parallels the S phase of the cell cycle and peripheral blood changes could follow both thymic and splenic modifications in apoptotic expression.
authors.affiliation: Dipartimento di Sanità Pubblica Veterinaria e Patologia Animale, Facoltà di Medicina Veterinaria, Università degli Studi di Bologna, Italy. sarli@vet.unibo.it
authors.forename: G
authors.initials: G
authors.lastname: Sarli
authors.forename: L
authors.initials: L
authors.lastname: Della Salda
authors.forename: L
authors.initials: L
authors.lastname: Zaccaro
authors.forename: M
authors.initials: M
authors.lastname: Bendinelli
authors.forename: G
authors.initials: G
authors.lastname: Piedimonte
authors.forename: P S
authors.initials: PS
authors.lastname: Marcato
mesh_terms: D000818:Animals; D017209:Apoptosis; D018791:CD4 Lymphocyte Count; D002415:Cats; D002453:Cell Cycle; D004195:Disease Models, Animal; D016181:Feline Acquired Immunodeficiency Syndrome / Q000276:immunology / Q000473:pathology*; D006801:Humans; D016089:Immunodeficiency Virus, Feline; D008198:Lymph Nodes / Q000473:pathology; D008214:Lymphocytes / Q000473:pathology; D008221:Lymphoid Tissue / Q000473:pathology*; D013045:Species Specificity; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000473:pathology; D013950:Thymus Gland / Q000473:pathology