Coimmunisation with type I IFN genes enhances protective immunity against cytomegalovirus and myocarditis in gB DNA-vaccinated mice.

Viral DNA vaccines encoding the glycoprotein B (gB) of cytomegalovirus provide partial protective immunity upon challenge with infectious virus. Although it is known that type I IFN can stimulate the adaptive immune response, their direct use in vaccines has been limited. Here we show that coimmunisation of type I IFN and gB CMV DNA constructs enhances protective immunity in mice. In vivo expression of IFN transgenes ranged from 1.2 to 2.0 x 10(4) IU/g tibialis anterior muscle. Viral titre in major target organs and the severity of acute CMV-induced myocarditis was reduced preferentially with either IFN-alpha 9 or IFN-beta, but not with IFN-alpha 6, coimmunisation. However, all IFN subtypes investigated markedly reduced chronic myocarditis in gB-vaccinated mice. The early antiviral IgG1 and IgG2a titres were enhanced with IFN-beta coimmunisation. TNF and IL-10 was increased in response to MCMV infection in mice coimmunised with IFN subtypes and viral gB DNA. Indeed T cells from IFN-inoculated mice reduced myocarditis upon in vivo transfer. These results suggest that select type I IFNs may act as a natural adjuvant for the immune response against CMV infection. Type I IFN DNA coimmunisation may provide increased efficacy for viral vaccines and subsequently modulate post-viral chronic inflammatory disorders.

Maturation of erythroid cells and erythroleukemia development are affected by the kinase activity of Lyn.

This study examined the impact of the tyrosine kinase Lyn on erythropoietin-induced intracellular signaling in erythroid cells. In J2E erythroleukemic cells, Lyn coimmunoprecipitated with numerous proteins, including SHP-1, SHP-2, ras-GTPase-activating protein, signal transducers and activators of transcription (STAT) 5a, STAT5b, and mitogen-activated protein kinase; however, introduction of a dominant-negative Lyn (Y397F Lyn) inhibited the interaction of Lyn with all of these molecules except SHP-1. Cells containing the dominant-negative Lyn displayed altered intracellular phosphorylation patterns, including mitogen-actiated protein kinase, but not erythropoietin receptor, Janus-activated kinase (JAK) 2, or STAT5. As a consequence, erythropoietin-initiated differentiation and basal proliferation were severely impaired. Y397F Lyn reduced the protein levels of erythroid transcription factors erythroid Kruppel-like factor and GATA-1 up to 90%, which accounts for the inability of J2E cells expressing Y397F Lyn to synthesize hemoglobin. Although Lyn was shown to bind several sites on the cytoplasmic domain of the erythropoietin receptor, it was not activated when a receptor mutated at the JAK2 binding site was ectopically expressed in J2E cells indicating that JAK2 is the primary kinase in erythropoietin signaling and that Lyn is a secondary kinase. In normal erythroid progenitors, erythropoietin enhanced phosphorylation of Lyn; moreover, exogenous Lyn increased colony forming unit-erythroid, but not burst forming uniterythroid, colonies from normal progenitors, demonstrating a stage-specific effect of the kinase. Significantly, altering Lyn activity in J2E cells had a profound effect on the development of erythroleukemias in vivo: the mortality rate was markedly reduced and latent period extended when either wild-type Lyn or Y397F Lyn was introduced into these cells. Taken together, these data show that Lyn plays an important role in intracellular signaling in nontransformed and leukemic erythroid cells.

Amiloride suppresses erythropoietin-induced proliferation and MAP kinase, but potentiates differentiation of J2E cells.

The J2E erythroid cell line proliferates and differentiates in response to erythropoietin (epo). Here we demonstrate that the diuretic amiloride can suppress normal and hormone-induced cell division in a dose-dependent manner. In the presence of amiloride, cell numbers did not increase, [3H]thymidine incorporation decreased, and fewer cells were observed in the S, G2, and M phases of the cell cycle. In addition, the levels of proliferating cell nuclear antigen, a subunit of DNA polymerase delta, fell. In marked contrast, epo-initiated differentiation was potentiated when J2E cells were cultured with the drug: the number of benzidine-positive cells increased, hemoglobin content per cell rose, and more morphologically mature cells were produced. Immunoblotting with anti-phosphotyrosine antibodies revealed that amiloride reduced the number of phosphorylated proteins in epo-stimulated cells. Moreover, the protein content of p42 and p44 MAP kinases was noticeably downregulated in amiloride-treated cultures. These data indicate that amiloride may interfere with epo-induced signaling cascades within J2E cells which result in restricted cell division and promotion of maturation.

Restriction fragment length polymorphisms of the human aldose reductase gene: a preliminary report.

Abnormal metabolism through the polyol pathway during episodes of hyperglycaemia is implicated in the development of the chronic complications of diabetes. Since aldose reductase is the first and ratelimiting enzyme of the polyol pathway, it is predicted that restriction fragment length polymorphisms at the aldose reductase gene locus may influence catalytic activity and determine individual susceptibility to the diabetic complications. This paper reports the existence of EcoRI and TaqI restriction fragment length polymorphisms at the human aldose reductase locus.