Reduced humoral immunity and atypical cell-mediated immunity in response to vaccination in cows naturally infected with bovine leukemia virus.
Bovine leukemia virus (BLV) is a retrovirus that is widely distributed across US dairy herds: over 83% of herds are BLV-infected and within-herd infection rates can approach 50%. BLV infection reduces both animal longevity and milk production and can interfere with normal immune health. With such a high prevalence of BLV infection in dairy herds, it is essential to understand the circumstances by which BLV negatively affects the immune system of infected cattle. To address this question, BLV- and BLV+ adult, lactating Holstein dairy cows were vaccinated with Bovi-Shield GOLD® FP® 5 L5 HB and their immune response to vaccination was measured over the course of 28days. On day 0 prior to vaccination and days 7, 14 and 28 post-vaccination, fresh PBMCs were characterized for T and B cell ratios in the periphery. Plasma was collected to measure titers of IgM, IgG1 and IgG2 produced against bovine herpesvirus 1 (BHV1), Leptospira hardjo and L. pomona, as well as to characterize neutralizing antibody titers produced against BHV1 and bovine viral diarrhea virus types 1 and 2. On day 18 post-vaccination, PBMCs were cultured in the presence of BHV1 and flow cytometry was used to determine IFNγ production by CD4+, CD8+ and γδ T cells and to investigate CD25 and MHCII expression on B cells. BLV+ cows produced significantly lower titers of IgM against BHV1, L. hardjo and L. pomona and produced lower titers of IgG2 against BHV1. γδ T cells from BLV+ cows displayed a hyper reactive response to stimulation in vitro, although no differences were observed in CD4+ or CD8+ T cell activation. Finally, B cells from BLV+ cows exhibited higher CD25 expression and reduced MHCII expression in response to stimulation in vitro. All together, data from this study support the hypothesis that BLV+ cows fail to respond to vaccination as strongly as BLV- cows and, consequently, may have reduced protective immunity when compared to healthy BLV- cows.
['Frie|Meredith C|MC|', 'Sporer|Kelly R|KR|', 'Wallace|Joseph C|JC|', 'Maes|Roger K|RK|', 'Sordillo|Lorraine M|LM|', 'Bartlett|Paul C|PC|', 'Coussens|Paul M|PM|']
D000818:Animals D057134:Antibodies, Neutralizing D000914:Antibodies, Viral D001402:B-Lymphocytes D001428:Bacterial Vaccines D002417:Cattle D016583:Enzootic Bovine Leukosis D005260:Female D007111:Immunity, Cellular D056724:Immunity, Humoral D007075:Immunoglobulin M D001909:Leukemia Virus, Bovine D008213:Lymphocyte Activation D016176:T-Lymphocyte Subsets D013997:Time Factors D014611:Vaccination D014765:Viral Vaccines
Vaccine BLV Antibody IFNγ T Cell MHCII