Spontaneous and mitogen-induced RNA synthesis by blood lymphocytes from bovine leukemia virus-infected and normal cows

Inhibition of protein kinase C results in decreased expression of bovine leukemia virus

“…RNase protection assay autoradiographs were digitized for densitometric analysis. BLV tax/rex signals were calculated relative to the bovine actin signal for each sample and graphed as the average percentage of control obtained in separate experiments with four individual BLV-seropositive cattle with PL. spontaneous blastogenesis is most pronounced in cultured PBMC from cattle with PL (59,61). This spontaneous blastogenesis is thought to be an antigen-specific proliferative response to BLV antigens produced during short-term culture (57, 59).…”

“…Mitogens such as concanavalin A and phytohemagglutinin have been reported to increase BLV expression in cultured PBMC from BLV-infected animals (12,19,20,42,56). Additionally, cultured PBMC from BLV-seropositive cattle affected with PL have been reported to have decreased responses to mitogens because of increased spontaneous [3H]thymidine incorporation (45,61). The spontaneous [3H]thymidine incorporation in cultured PBMC from cows with PL can be markedly reduced by anti-BLV serum (57,59), and the inhibitory activity of anti-BLV serum can be reversed with purified BLV (59), which suggests that the spontaneous blastogenic response is viral antigen specific.…”

Interactions between bovine retroviruses and the host immune system

“…The limited data on cell-mediated responses of clinically healthy, BLVinfected cattle appear to be in conflict. There have been several reports that lymphocytes from BLV-infected cattle with PL have reduced blastogenic responses to mitogens, as measured by stimulation indices (Weiland and Straub, 1976, Villouta et al,1988. These results appear to have been due to the high background levels of proliferation in BLV-infected cattle (see SLP), since lymphocyte proliferative responses to Con A, PHA, and PWM of BLV+, non-PL animals was comparable to that of non-infected animals when DCPM were compared .…”