Conclusions

1. Department of Virology Unique sequence features of the Adenovirus 31 prototype complete genomic sequence are conserved in clinical isolates from cases of disseminated infection Sören Hofmayer, Ijad Madisch, Fabienne Rehren, Albert Heim 1 Department of Virology, Medizinische Hochschule Hannover, Hannover, Germany Introduction One of the most severe forms of adenovirus infection is the life threatening disseminated disease, frequently caused by serotypes of species C. Recently, type 31 from species A (HAdV-A31) also caused disseminated infections in stem cell transplanted children in several countries of the EU. HAdV-A31 is now clearly associated with infections of stem cell transplant recipients. This is in contrast to the self limiting enteric infections usually caused by other species HAdV-A viruses, and the closely related enteric viruses HAdV-F. • Study Design • complete genomic sequencing of the prototype strain of HAdV-A31 • primer walking strategy • Search for conserved DNA and amino acid motifs • sequencing of five gene regions relevant for XXXXof seven clinical isolates • comparative sequence analysis of the isolates and the prototype strain For the CR-1 beta 29.4K ORF a V-set domain (immunoglobulin like domain) was predicted by the PFAM software. This domain is not present in the closely related HAdV-A12 but in the newly discovered HAdV-G52. It may interact with cell-cell recognition, cell-surface receptors, and the immune system . The 28.6K ORF (CR1 alpha) of HAdV-A31 contains a further Immunoglobulin-like domain, which may be involved in protein-protein and protein-ligand interactions. E1B region While the first 145 aa of 18.3K (homolog to small T antigen) share a homology of 93,1% to HAdV-A12, the C-terminus is highly divergent (27.7% identity). E1B 19K is essential for immune escape and has antiapoptotic features. Amino acid comparison of the 53K ORF (homolog to large T antigen) with HAdV-A12 revealed a high sequence divergence between res 38 – 100 (55,5%) in contrast to a homology of 78,6% in the p53 repressing C-terminal domain. Clinical Isolates Overall, clinical isolates were closely related to the prototype (99,2 (E3 CR1-beta) to 100% (fiber knob) homology) 5 isolates had three identical amino substitutions in the E3 proteins. Results The genome of HAdV-A31 is 33763 bp in length. The plus strand has a base composition of 22.89% G, 23.48% C, 27.49% A and 26.14% T, with a GC content of 46.36%. The phylogenetic tree of the complete genomic HAdV-A31 DNA sequence and complete genomic sequences of representative members of each HAdV species. Predicted ORF of HAdV-A31 34 coding regions which are homolog to already described gene products of HAdV-A12 were found in HAdV-A31. Graphical alignments (LAGAN) show the close relationship between HAdV-A31 and -A12 with exception of the coding regions for immunogenic determinants (Hexon, Fiber) and surprisingly the immunomodulating E3 gene region. Unique motifs in the immunomodulating E3 region The 12.5K ORF (RID-beta) lacks a C-terminal phosphorylation site but has additional phosphorylation sites in the initial and central protein region. This may affect its function in internalization and degradation of the apoptosis receptor CD95 (Fas/APO-1). Conclusions HAdV-A31 is closely related to HAdV-A12, but shows several interesting sequence features in the E1 and E3 region which code for proteins interacting with innate immunity, immune recognition and apoptosis. Isolates from these patients were closely related to the prototype sequence but show a cluster of point mutations in the E3 region. This may lead to a persistent HAdV-A31 infection and to more frequent reactivations and disease manifestations in bone marrow transplant recipient. MHH Institut für Virologie Carl-Neuberg-Straße 1, 30625 Hannover Heim.Albert@mh-hannover.de www.mh-hannover.de