T Lymphocyte Population Dynamics and Function Following a Primary Bovine Herpesvirus Type-1 Infection

Abstract

Following a primary bovine herpesvirus-1 (BHV-1) infection the concanavalin A (Con A) induced proliferative responses of peripheral blood T lymphocytes were suppressed. This suppression occurred in the absence of detectible serum suppressor factors, suppressor cell activity or decreased accessory cell function. However, regression analysis demonstrated a significant correlation between the percentage of T lymphocytes present within the peripheral blood mononuclear cell (PBMC) population and the amplitude of Con-A-induced lymphocyte proliferative responses (LPR). Direct evidence that a numerical deficit of responder T lymphocytes was limiting LPR was obtained by using an immunomagnetic microsphere (IMM) negative enrichment protocol to produce a PBMC population with a constant percentage (75 +/- 6%) of T lymphocytes. The Con-A-induced LPR of these enriched T lymphocytes remained constant following BHV-1 infection. Flow cytometric (FC) analysis of PBMC indicated that the decreased percentage of circulating T lymphocytes, associated with BHV-1 infection, was caused primarily by a selective depletion of the BoT8 subset. These FC data were consistent with the indirect evidence of increased TH activity, as indicated by elevated Con A-induced IL-2 production. Thus, 2 to 5 days following viral infection, the circulating T lymphocytes were activated as shown by elevated IL-2 production, increased recombinant bovine IL-2 (rBo

Proinflammatory cytokines and viral respiratory disease in pigs

“…Transplacental infection occurs in late gestating sows, but is beyond the scope of this review. In experimentally infected pigs, PRRSV replicates in nasal turbinates, tonsils, lungs, several lymph nodes, spleen, liver, kidney, thymus, brain, heart, bone marrow and choroid plexus [32,46,101,107]. Nasal secretions are inconsistently virus positive and plasma or serum samples are more appropriate for virus isolation than nasal swabs [32].…”

“…Macrophages are the principal virus target cells in all organs. In the lungs, PRRSV antigens have been detected in macrophages of the alveolar spaces and alveolar septa and, more rarely, in type 2 pneumocytes [32,39,46]. On the contrary, only a small fraction of the total alveolar macrophage (AM) population (no more than about 2% of lavaged alveolar cells) are found to be PRRSV antigen positive [32,39,81].…”

“…Still, limited experimental data suggest that IFN-α may be involved in tissue lymphocyte or neutrophil infiltration. For example, local production of IFN-α/β in the lungs of virus-infected calves is temporally correlated with an influx of CD8+ T lymphocytes into the lung parenchyma [46]. Also, virus-induced IFN-α/β production in the lymph nodes of mice is associated with a striking neutrophil infiltration [104].…”

Bovine herpesvirus-1 infects activated CD4+ lymphocytes.

“…responses of peripheral blood mononuclear cells by BHV-1 may be due to a selective depletion of certain lymphocyte populations or by changes in lymphocyte trafficking (Filion et al, 1981 ;Griebel et al, 1987Griebel et al, , 1988. Recent studies have shown that proteins produced by herpesviruses interfere with class I mediated antigen presentation.…”

A Mutation in the Latency-Related Gene of Bovine Herpesvirus 1 Disrupts the Latency Reactivation Cycle in Calves

“…BHV-1 is not the sole infectious agent associated with shipping fever, but it initiates the disorder by immunosuppressing infected cattle, which results in secondary bacterial infections and pneumonia. Increased susceptibility to secondary infection correlates with depressed cell-mediated immunity after BHV-1 infection (4,(10)(11)(12). CD8…”