Quantitation of cytokine gene expression by real time PCR in bovine milk and colostrum cells from cows immunized with a bovine rotavirus VP6 experimental vaccine

In a previous work, VP6 recombinant protein was produced using baculovirus system and it was evaluated in a colostrum-deprived calf model. This vaccine was able to protect calves against viral challenge without inducing neutralizing antibodies (NAb), suggesting that another immunological effectors were involved in the protection observed. In this work, groups of cows (n= 4) were immunized in the last third of gestation with a bovine rotavirus (BRV) experimental vaccine and with a VP6 subunit vaccine. At birth, colostrums from vaccinated and non-vaccinated cows were processed and viable colostral mononuclear cells were obtained. With the purpose of determining the cytokine patterns generated by cells from immune secretions (colostrums and milk), a relative quantification by real time PCR was standardized. Quantitative real time PCR (qPCR) was used to determine transcript levels of IL-4, IL-6, IL-10, IL-12, IFN-γ and IFN-α from these cells. Colostral and milk mononuclear cells expressed a different cytokine transcript expression pattern regarding the vaccine used. These results demonstrated that the colostral cellular population was active and could exert its action influencing the final immune response.