RESUMO
Dendritic cells (DC) are potent inducers of acquired immunity due to their ability to present antigens in the context of a costimulatory environment and consequently serve an essential role in vaccine efficacy. Strategies to enhance their function, such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4 treatment to induce DC differentiation from peripheral blood monocytes, may therefore be useful as vaccine adjuvants. We now have evaluated the effect of recombinant GM-CSF on the differentiation of DC in swine. GM-CSF mRNA was readily detected in porcine splenocytes, with increased levels following treatment of the cells with ConA and LPS. Porcine GM-CSF was cloned and expressed in the methylotrophic yeast, Pichia pastoris, as a glycosylated protein that induced proliferation of porcine bone marrow cells. P. pastoris-derived GM-CSF induced expression of antigen presenting (MHC class II) and costimulatory (CD80-CD86) molecules and enhanced antigen presenting cell (APC) function consistent with the induction of functional DC. Thus, recombinant GM-CSF produced by P. pastoris may be a potent adjuvant for swine vaccines.
Assuntos
Diferenciação Celular/efeitos dos fármacos , Células Dendríticas/citologia , Células Dendríticas/efeitos dos fármacos , Fator Estimulador de Colônias de Granulócitos/farmacologia , Pichia/genética , Suínos/imunologia , Animais , Apresentação de Antígeno/efeitos dos fármacos , Antígenos de Superfície/análise , Antígenos de Superfície/metabolismo , Células da Medula Óssea/citologia , Células da Medula Óssea/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Células Dendríticas/imunologia , Relação Dose-Resposta Imunológica , Expressão Gênica , Fator Estimulador de Colônias de Granulócitos/genética , Fator Estimulador de Colônias de Granulócitos/metabolismo , Imunofenotipagem , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas RecombinantesRESUMO
Alpha-Fetoprotein (AFP) is a 68 kDa glycoprotein expressed at high levels by the fetal liver and yolk with transcription repressed to very low levels after birth. Transfer of fetal AFP through the placenta into the circulation of the mother is correlated with remission of rheumatoid arthritis, multiple sclerosis, and other autoimmune disorders. AFP is therefore under development as a biopharmaceutical for the treatment of autoimmune diseases. The clinical evaluation of AFP requires the production of hundreds of grams of highly purified and biologically active protein. We have produced goats that express a form of the human AFP transgene under the control of the beta-casein promoter. In this form of rhAFP, the single N-linked glycosylation site was removed by mutagenesis (N233Q). Here, we describe a purification protocol for this recombinant human (rh)AFP from the milk of these transgenic goats. A three-column procedure was developed to produce gram quantities of highly purified rhAFP. Near- and far-UV circular dichroism spectra of human umbilical cord blood AFP and rhAFP were essentially identical, suggesting that the structure is not affected by removal of the glycosylation site. Furthermore, the cell binding and pharmacokinetics of purified rhAFP were similar to human AFP isolated from cord blood. Our results demonstrate that an active form of rhAFP can be produced on industrial scale by expression in transgenic goat milk.