Semisynthetic glycoconjugate vaccine candidate against Streptococcus pneumoniae serotype 5

Glycoconjugate vaccines based on isolated capsular polysaccharide (CPS) save millions of lives annually by preventing invasive pneumococcal disease caused by Streptococcus pneumoniae Some components of the S. pneumoniae glycoconjugate vaccine Prevnar13 that contains CPS antigens from 13 serotypes undergo modifications or degradation during isolation and conjugation, resulting in production problems and lower efficacy. We illustrate how stable, synthetic oligosaccharide analogs of labile CPS induce a specific protective immune response against native CPS using S. pneumoniae serotype 5 (ST-5), a problematic CPS component of Prevnar13. The rare aminosugar l-PneuNAc and a branched l-FucNAc present in the natural repeating unit (RU) are essential for antibody recognition and avidity. The epitope responsible for specificity differs from the part of the antigen that is stabilized by chemical modification. Glycoconjugates containing stable, monovalent synthetic oligosaccharide analogs of ST-5 CPS RU induced long-term memory and protective immune responses in rabbits superior to those elicited by the ST-5 CPS component in multivalent Prevnar13.

Dual Infection with Bluetongue Virus Serotypes and First-Time Isolation of Serotype 5 in India

Bluetongue is endemic in India and has been reported from most Indian states. Of late, the clinical disease is most frequently seen in the states of Andhra Pradesh, Telangana (erstwhile Andhra Pradesh state), Tamil Nadu and Karnataka. Our analysis of diagnostic samples from bluetongue outbreaks during 2010-2011 from the state of Karnataka identified bluetongue virus (BTV) serotype 5 (BTV-5) for the first time in India. One of the diagnostic samples (CH1) and subsequent virus isolate (IND2010/02) contained both BTV-2 and BTV-5. Segment 2 (seg-2) sequence data (400 bp: nucleotides 2538-2921) for IND2010/02-BTV5, showed 94.3% nucleotide identity to BTV-5 from South Africa (Accession no. AJ585126), confirming the virus serotype and also indicating that Seg-2 was derived from a Western topotype, which is in contrast to serotype 2, that belongs to an Eastern topotype. BTV-5 has been recently reported from Africa, China, French islands and the Americas. Although the exact source of the Indian BTV-5 isolate is still to be confirmed, recent identification of additional exotic serotypes in India is of real concern and might add to the severity of the disease seen in these outbreaks.

Epidemic of invasive pneumococcal disease, western Canada, 2005-2009

In Canada before 2005, large outbreaks of pneumococcal disease, including invasive pneumococcal disease caused by serotype 5, were rare. Since then, an epidemic of serotype 5 invasive pneumococcal disease was reported: 52 cases during 2005, 393 during 2006, 457 during 2007, 104 during 2008, and 42 during in 2009. Of these 1,048 cases, 1,043 (99.5%) occurred in the western provinces of Canada. Median patient age was 41 years, and most (659 [59.3%]) patients were male. Most frequently representing serotype 5 cases (compared with a subset of persons with non-serotype 5 cases) were persons who were of First Nations heritage or homeless. Restriction fragment-length polymorphism typing indicated that the epidemic was caused by a single clone, which multilocus sequence typing identified as sequence type 289. Large pneumococcal epidemics might go unrecognized without surveillance programs to document fluctuations in serotype prevalence.