McNallan, Kelly T.

Abstract Immunostimulatory CpG motifs in synthetic oligonucleotides can be effective adjuvants for the priming of CTLs. We first observed that a single male-specific peptide (KCSRNRQYL) (HY2) was more efficient than another male-specific peptide (WMHHNMDLI) (HY1) at priming IFN-γ-secreting CTLs in vivo when combined with lipid A and CpG and that it also visibly precipitated CpG. The addition of the six N-terminal residues (KCSRNR) from HY2 to HY1 yielded a peptide, KCSRNR-HY1, that both precipitated CpG and primed increased numbers of HY1-specific CTLs. We refer to this type of peptide as a primotope that includes a class I binding peptide tailed with amino acids that increase priming. Ala residues were substituted for the Arg/Lys residues (ACSANA-HY1), and these substitutions did not reduce in vivo priming potential. However, the substitution of Ala for Cys (KASRNR-HY1) resulted in the complete loss of priming, demonstrating the importance of Cys for in vivo priming when mixed with CpG. This result suggested that increased priming was based in disulfide bonding between Cys residues and internal phosphorothioate groups of synthetic CpG. The addition of Cys-bearing primotopes to radiolabeled CpG with a single thioate group resulted in the appearance of a new band that was inhibited by 1) Cys > Ala substitution and 2) reduction and alkylation of CpG. These results reveal a novel mechanism for complexing class I binding peptides and CpG adjuvant for development of new peptide-adjuvant combinations for vaccines for cancer and infectious diseases.

Abstract Juvenile dermatomyositis (JDM) is a multisystem autoimmune disease that at times resembles chronic graft-vs-host disease. This led us to suggest that nonself cells may play a role in the disease process. In this study we examined the relationship between HLA genotype and the presence of maternally derived chimeric cells in JDM patients and healthy controls, and assessed immunologic activity in the chimeric cells. We identified chimeric cells more often in children with JDM (60 of 72) than in their unaffected siblings (11 of 48) or in healthy controls (5 of 29). The presence of chimerism in the JDM patients, their healthy siblings, and unaffected control children was associated with a HLA-DQA1*0501 allele in the mother (p = 0.011). Further, we show that maternally transferred chimeric T cells are responsive to the host’s (JDM childs’) lymphocytes (33.75 ± 8.4 IFN-γ-producing cells from JDM cells vs 5.0 ± 1.25 from maternal cells), and that this is a memory response. These combined data indicate that chimeric cells play a direct role in the JDM disease process and that the mother’s HLA genotype facilitates the transfer and/or persistence of maternal cells in the fetal circulation.