Interferon gamma production during bovine respiratory syncytial virus (BRSV) infection is diminished in calves vaccinated with formalin-inactivated BRSV.
Formalin-inactivated respiratory syncytial virus (FI-RSV) vaccination has been associated with severe disease in humans. Research in mice suggests that FI-RSV may prime for decreased interferon gamma (IFN-gamma) production at subsequent infection. Interferon-gamma production by peripheral blood mononuclear cells (PBMC) was measured following challenge of calves vaccinated with FI-BRSV to determine whether a similar mechanism is operative in a host naturally susceptible to RSV. Eight-week old male Holstein calves were administered FI-BRSV and mock challenge (V/M, n = 6); mock vaccination and BRSV challenge (M/C, n = 6) or FI-BRSV and BRSV challenge (V/C, n = 7). Vaccine was administered twice at a 2-week interval; challenge followed one month later. On days 0, 5 and 10 postchallenge (PC), PBMC were stimulated in vitro for 24 h with live BRSV, concanavalin A (positive control) or spent media (negative control). Supernatants were assayed for IFN-gamma using ELISA. Interferon-gamma production by BRSV-stimulated PBMC was increased in M/C and V/C calves as compared to V/M calves on day 5 PC (p < 0.015); and increased in M/C calves compared to V/C and V/M calves on day 10 PC (p < 0.015). Over time postchallenge, a significant increase in IFN-gamma production by BRSV-stimulated PBMC was seen in M/C calves (p < 0.025) but not in V/C calves. FI-BRSV vaccination of calves led to diminished IFN-gamma production postchallenge. Decreased IFN-gamma production may have contributed to impaired viral clearance and enhanced disease in FI-BRSV vaccinated calves.
Woolums
A R
AR
Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis 95616, USA.
Singer
R S
RS
Boyle
G A
GA
Gershwin
L J
LJ
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000378:metabolism* / Q000517:prevention & control; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005557:Formaldehyde; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000097:blood; D007963:Leukocytes, Mononuclear / Q000378:metabolism / Q000821:virology; D008297:Male; D051379:Mice; D018357:Respiratory Syncytial Virus Infections / Q000378:metabolism / Q000517:prevention & control / Q000662:veterinary*; D018112:Respiratory Syncytial Virus, Bovine; D014613:Vaccines, Attenuated; D014765:Viral Vaccines
D014613:Vaccines, Attenuated; D014765:Viral Vaccines; D005557:Formaldehyde; D007371:Interferon-gamma