Constitutive expression of types 1 and 2 cytokines by alveolar macrophagesfrom feline immunodeficiency virus-infected cats

Evidence suggests that feline immunodeficiency virus (FIV), causes pulmonar y immunodeficiency. The overall objective of this study was to explore FIV- induced alterations in cell counts and cytokine gene expression in the pulm onary compartment during the acute stage infection. Bronchoalveolar lavage (BAL) cells were collected from FIV-infected and control cats at 0, 4, 10, and 16 weeks post-FIV infection for phenotype and cytokine analysis. The ma jor change in BAL cellular populations following FIV-infection was the deve lopment of a neutrophilia. Total BAL cell counts and relative numbers of al veolar macrophages: (AM), eosinophils, and lymphocytes remained similar in both groups. The RT-qcPCR analyses of AM purified from BAL showed constitut ive expression of TNF alpha IL6 and IL10 mRNAs; that peaked during the acut e stage of infection then declined. The TNF alpha and IL6 bioactive protein secretion showed a similar response. In contrast, IFN gamma expression inc reased progressively with time after infection and paralleled a progressive increase in FIV-gag mRNA in AM. The IL12 p40 expression also differed from the other cytokines in that there was a progressive decrease in the number of cats with AM IL12 expression following FIV infection. Infection of AM i n vitro with FIV also caused an increase in TNF alpha and IL6 mRNA and bioa ctive protein suggesting that the increased cytokine response by AM followi ng infection of cats with FIV is an intrinsic characteristic of FIV-infecte d AM. In summary, pulmonary immune changes seen in FIV-infected cats are si milar to those seen in HIV-infected human patients. (C) 2001 Elsevier Scien ce B.V. All rights reserved.