Immune Response in Holstein Calves Vaccinated at Six Months of Age

Autor(es)

Baccili, Camila Costa ^[1] ; Marques, Raquel de Sousa ^[1] ; Fontes Novo, Sylvia Marquart ^[1] ; Silva, Bruno Toledo ^[1] ; Pituco, Edviges Maristela ^[2] ; Gomes, Viviani ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Coll Vet Med & Anim Sci, Dept Internal Med, BR-05508270 Sao Paulo, SP - Brazil

^[2] Inst Biol, Lab Bovine Viruses, Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Acta Scientiae Veterinariae; v. 43, SEP 28 2015.
• Citações Web of Science: 0

Resumo

Background: Calves are agammaglobulinemic and immature at birth and their immunological defense must be improved by colostrum, although, maternal antibodies decrease after two months of age and calves are susceptible to Bovine Respiratory Disease Complex (BRDC). Then, this research evaluated the immune response to BVDV and BoHV-1 in young calves to prevent BRDC. Materials, Methods \& Results: Ten male Holstein calves were distributed in two groups with five animals on each: non-vaccinated VAC (-) and vaccinated VAC (+). Calves were vaccinated twice at 180 and 210 days of age. It was selected a commercial multivalent vaccine containing inactivated isolated of BVDV type-1 (strains 5960) and BVDV type-2 (strains 53637), and modified-live BoHV-1 (strains RLB103), with Quil A, cholesterol and Amphigen as adjuvant. The immune response (IR) was evaluated at 180 (T0), 210 (T1) and 240 (T2) days of life by serum neutralization (SN) and immunophenotyping. Specific antibodies to BVDV were detected in 40% (2/5) and 60% (3/5) of vaccinated calves at T1 and T2, respectively. Specific antibodies (Abs) to BoHV-1 were observed in 40% (2/5) at T1 and 100% (5/5) at T2 in the VAC (+) group. Titers of Abs to BoHV-1 increase from T0 to T2 (P = 0.034) in VAC (+). Moreover, geometric mean titer (GMT) to BoHV-1 in VAC (+) group was higher than VAC (-) after secondary IR in T2 (P = 0.006). The proportion of the markers T lymphocytes subpopulation (CD3(+), CD4(+), CD8(+) and WC1(+)) and B lymphocytes (CD21(+)) were similar in the two experimental groups, while the expression of the CD25(+) marker by gamma-delta (WC1(+)) was higher in VAC (+) at T1. Discussion: Low titers of circulating Abs could be observed just for BoHV-1 in the calves from VAC (-) at T0, probably due to remaining Abs from dams transferred by colostrum intake. This fact indicates the need of appropriate vaccination schedules to prevent the virosis in dairy heifers. The low rate of seroconversion to BVDV and BoHV-1 at T1 is compatible with the pattern of the primary immune response, usually weak and slow. The greatest response at the time T2, after booster, was observed due to the presence of memory cells from first vaccination, responsible for the greater intensity and duration of Abs production. The specific immune response to BoHV-1 higher than BVDV could be attributed to the composition of the commercial vaccine that had live attenuated strain of BoHV-1, wich demonstrates greater intensity and duration than inactivated BVDV strain. We could not verify cellular immune response induced by the commercial selected vaccine. The labeling of the blood leukocytes held in this research, without in vitro antigen-stimulation, limited the assessment of IR caused strictly by the immunogen. Thus, environmental pathogens may have contributed to these results, impairing detection of differences between groups. Thus, calves vaccinated at six months old developed humoral immune response, especially for modified-live BoHV-1. In contrast, the animals presented lower intensity of response to the inactivated BVDV. Moreover, cellular immune response after vaccination was not detected under the conditions which this research was conducted. (AU)

• Processo FAPESP: 12/02129-8 - Desenvolvimento da resposta imune específica em bezerros e sua influência na resposta vacinal ao vírus da diarréia viral bovina
• Beneficiário: Viviani Gomes
• Modalidade de apoio: Auxílio à Pesquisa - Regular