Immune response of bovines stimulated by synthetic vaccine SBm74621 against Rhipicephalus (Boophilus) microplus.

Ten-month-old calves Bos taurus taurus were immunized with three doses of SBm74621 with saponin as an adjuvant at 30-day intervals and were evaluated for IgG isotypes, phenotype circulating lymphocytes and changes in the lymph nodes (LN). SBm74621 stimulated the production of predominantly IgG1-isotype IgG antibodies. The lymph nodes exhibited activation at the seventh day after the first immunization, with areas of paracortical and interfollicular hyperplasia and the early formation of germinal centers (GC). Fifteen days after the first immunization, the GC exhibited compartmentalization of cellular populations, a light zone (LZ), a dark zone (DZ) and a mantle. At the same time, hyperplasia of the medullary cords was observed with cells associating with DC cells. Seven days after the first immunization, apoptosis in the DZ and in the paracortical region became evident. By day 15, there was an increase in the medullary cords, which became more numerous at days 35 and 42. PAP-positive cells were found in the paracortical region, medullary cords and GC 7 days after the first immunization. At day 35, there were further strongly PAP-positive cells in the medullary cords. By comparison, none of these changes were observed in the lymph nodes of control groups at any of the days analyzed. The number of CD21+ lymphocytes increased in the immunized groups after the first inoculation, with a maximum number observed at 15 and 10 days after the first and third immunizations, respectively. Compared to pre-immunization counts, the percentage of WC1+ gd T-lymphocytes displayed more variation, increasing 5 days after the second immunization but decreasing over the following days. According to the results, the synthetic anti Rhipicephalus microplus vaccine elicits a complete immune response being T-dependant

Concentrações de imunoglobulinas G em colostro de vacas mestiças holandês-zebu Colostral immunoglobulin G concentrations in crossbred holstein-zebu dairy cows

Oitenta e oito vacas leiteiras mestiças holandês-zebu (HZ) foram distribuídas de acordo com a percentagem de grau de sangue holandês em quatro grupos: Grupo 1 = animais com menos de 70% de grau de sangue holandês (19 vacas); Grupo 2 = animais com 75% de grau de sangue holandês, que equivale a ¾ HZ (46 vacas); Grupo 3 = mestiços entre 80 e 90% de grau de sangue holandês, que corresponderam a 13/16 HZ e 7/8 HZ (11 vacas); Grupo 4 = vacas com mais de 90% de grau de sangue holandês (12 vacas). Após o parto, amostras de colostro da primeira ordenha foram colhidas e, posteriormente, submetidas à imunodifusão radial simples para determinações dos níveis de imunoglobulinas G (IgG). Os resultados obtidos permitiram concluir que as concentrações de IgG não são influenciadas pelos graus de sangue estudados e seus valores médios (145,94mg/m<img src="http:/img/fbpe/cr/v31n6/a19img01.gif">) são muito superiores aos relatados para animais de raças taurinas puras. Por esse motivo, não se justifica o emprego de métodos artificiais de fornecimento do colostro em se tratando de mestiços HZ. Ademais, o nível elevado de IgG observado no colostro sugere que a adoção da prática da mamada natural assistida seja adequada para assegurar que, na maioria das vezes, os neonatos não venham a apresentar falhas de transferência de imunidade passiva.<br>Eighty-eight healthy crossbred holstein-zebu (HZ) dairy cows were distributed in four groups as follow: Group 1 = less than 70% HZ (19 cows); Group 2 = 75% HZ animals, corresponding to ¾ HZ (46 cows); Group 3 = crossbred animals between 80 to 90% HZ, corresponding to 13/16 HZ and 7/8 HZ (11 cows); Group 4 = cows more than 90% HZ (12 animals). After birth, colostrum samples were obtained from each cow and than were analyzed for immunoglobulin G (IgG) concentration by single radial immunodifusion assay. IgG colostral concentrations were not influenced by group of crossbred HZ and its mean concentration (145.97mg/m<img src="http:/img/fbpe/cr/v31n6/a19img01.gif">) were higher than that related for purebreds Bos taurus dairy cows. Considering these results, it was concluded that artificial methods of feeding colostrum to crossbred HZ calves are not necessary. Probably, assisted natural sucking as soon after birth as possible is enough to get passive immune transfer