Non-Mutated Nucleophosmin 1 Is Recognized by the CD8+ T Lymphocytes of an AML Patient after the Transplantation of Hematopoietic Stem Cells from an HLA-Haploidentical Donor.

Nucleophosmin (NPM1, B23) is a multifunctional phosphoprotein expressed in all tissues. The protein is mainly localized in nucleoli. In hematological malignancies, NPM1 belongs to commonly altered genes. Its mutation, always heterozygous, leads to the re-localization of the NPM1 protein from the nucleolus to the cytoplasm (NPM1c+). NPM1c+ is found in 30% of acute myeloid leukemia (AML). Our study showed that an AML patient, whose leukemia cells carried the NPM1c+ mutation and who was the recipient of allogeneic HSCT from a haploidentical donor, raised a robust allorestricted CD8+ T cell response directed against the NPM1wt protein. Favourably, the response against NPM1wt was not accompanied by side effects such as GvHD. Moreover, the induction of a high NPM1wt-specific response coincided with the decrease in NPM1c+ transcripts detected, implying a beneficial graft versus leukemia effect. On the basis of these results, we suppose that TCRs from allorestricted NPM1wt-specific T cells are worth studying in other recipients of grafts from haploidentical donors as a possible tool for TCR gene therapy.

Chemokine binding protein vCCI attenuates vaccinia virus without affecting the cellular response elicited by immunization with a recombinant vaccinia vector carrying the HPV16 E7 gene.

Viral CC chemokine inhibitor (vCCI) of the clone P13 vaccinia virus (VACV) strain PRAHA lacks eight amino acids in the signal peptide sequence. To study the influence of vCCI on virus biology, a virus with the vCCI gene coding for a prolonged signal sequence was prepared. We found that secreted vCCI attenuated the virus in vivo, and that it correlated with decreased levels of RANTES, eotaxin, TARC, and MDC in the blood in comparison with the parental virus. We determined the influence of vCCI on the CTL response against VACV E3((140-148)) (VGPSNSPTF) and HPV16 E7((49-57)) (RAHYNIVTF) H-2D(b)-restricted epitopes. The examination of the specific CTL response elicited by immunization with the recombinant VACV-expressing tumor-associated HPV16 E7 antigen by IFN-γ ELISPOT showed that the immunogenicity of the recombinant VACV-producing secretory vCCI was similar to that of the parent virus or deletion mutant in the C23L/B29R locus. Immunization with the secretory vCCI-producing recombinant virus has a lower therapeutic anti-tumor effect against TC-1 tumors. Viral CCI downregulated the E7-specific response induced by gene gun immunization with the DNA vaccines pBSC-SigE7 LAMP and pBSC-vCCI. We also observed that the immune response against vCCI elicited by the DNA vaccine did not affect the multiplication of VACV in vivo.

Immunization with WT1-derived peptides by tattooing inhibits the growth of TRAMP-C2 prostate tumor in mice.

The expression of the transcription factor encoded by the Wilms tumor gene 1 (WT1) is associated with a variety of human cancers. WT1 protein has been reported to serve as a target antigen for tumor-specific immune responses. We observed that the immunization of mice with peptide vaccines derived from WT1 in a mixture with the CpG adjuvant (ODN 1826) by tattoo administration was superior to subcutaneous delivery of the peptides in combination with CpG formulated with the mineral oil adjuvant or a DNA vaccine or a recombinant vaccinia virus vaccine expressing the truncated WT1 protein. Tattooing with the WT1122-140 and WT1126-134 peptide elicited the response of WT1-specific interferon-γ-producing T cells. Peptide vaccine administered with a tattoo device had an antitumor effect on the growth of the prostate tumor cell line TRAMP-C2, provided that the transforming growth factor-ß produced by tumor cells was neutralized by anti-TGFß monoclonal antibody. The treatment of the tumor-bearing mice with 5-azadeoxycytidine or poly IC did not work in synergy with the peptide vaccine.

Attenuation of vaccinia virus by the expression of human Flt3 ligand.

BACKGROUND: Vaccinia virus, one of the best known members of poxvirus family, has a wide host range both in vivo and in vitro. The expression of Flt3 ligand (FL) by recombinant vaccinia virus (rVACV) highly influenced properties of the virus in dependence on the level of expression. RESULTS: High production of FL driven by the strong synthetic promoter decreased the growth of rVACV in macrophage cell line J774.G8 in vitro as well as its multiplication in vivo when inoculated in mice. The inhibition of replication in vivo was mirrored in low levels of antibodies against vaccinia virus (anti-VACV) which nearly approached to the negative serum level in non-infected mice. Strong FL expression changed not only the host range of the recombinant but also the basic protein contents of virions. The major proteins - H3L and D8L - which are responsible for the virus binding to the cells, and 28 K protein that serves as a virulence factor, were changed in the membrane portion of P13-E/L-FL viral particles. The core virion fraction contained multiple larger, uncleaved proteins and a higher amount of cellular proteins compared to the control virus. The overexpression of FL also resulted in its incorporation into the viral core of P13-E/L-FL IMV particles. In contrary to the equimolar ratio of glycosylated and nonglycosylated FL forms found in cells transfected with the expression plasmid, the recombinant virus incorporated mainly the smaller, nonglycosylated FL. CONCLUSIONS: It has been shown that the overexpression of the Flt3L gene in VACV results in the attenuation of the virus in vivo.

Clinical manifestation and molecular genetic characterization of MYH9 disorders.

Currently, the May-Hegglin anomaly (MHA), Sebastian (SBS), Fechtner (FTNS) and Epstein (EPS) syndrome are considered to be distinct clinical manifestations of a single disease caused by mutations of the MYH9 gene encoding the heavy chain of non-muscle myosin IIA (NMMHC-IIA). Manifestations of these disorders include giant platelets, thrombocytopenia and combinations of the presence of granulocyte inclusions, deafness, cataracts and renal failure. We examined 15 patients from 10 unrelated families on whom we performed immunostaining of NMMHC-IIA in blood samples. Polymerase chain reaction (PCR) analysis of selected exons of the MYH9 gene revealed mutations in nine samples with one novel mutation. Results of fluorescence and mutational analysis were compared with clinical manifestations of the MYH9 disorder. We also determined the number of glycoprotein sites on the surface of platelets. Most patients had an increased number of glycoproteins, which could be due to platelet size.