Serotype

About: Serotype is a research topic. Over the lifetime, 9010 publications have been published within this topic receiving 272287 citations. The topic is also known as: serovar & Serotype.

Pathogenesis of dengue: challenges to molecular biology

Abstract: Dengue viruses occur as four antigenically related but distinct serotypes transmitted to humans by Aedes aegypti mosquitoes. These viruses generally cause a benign syndrome, dengue fever, in the American and African tropics, and a severe syndrome, dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), in Southeast Asian children. This severe syndrome, which recently has also been identified in children infected with the virus in Puerto Rico, is characterized by increased vascular permeability and abnormal hemostasis. It occurs in infants less than 1 year of age born to dengue-immune mothers and in children 1 year and older who are immune to one serotype of dengue virus and are experiencing infection with a second serotype. Dengue viruses replicate in cells of mononuclear phagocyte lineage, and subneutralizing concentrations of dengue antibody enhance dengue virus infection in these cells. This antibody-dependent enhancement of infection regulates dengue disease in human beings, although disease severity may also be controlled genetically, possibly by permitting and restricting the growth of virus in monocytes. Monoclonal antibodies show heterogeneous distribution of antigenic epitopes on dengue viruses. These epitopes serve to regulate disease: when antibodies to shared antigens partially neutralize heterotypic virus, infection and disease are dampened; enhancing antibodies alone result in heightened disease response. Further knowledge of the structure of dengue genomes should permit rapid advances in understanding the pathogenetic mechanisms of dengue.

Identification of vaccine candidates against serogroup B meningococcus by whole-genome sequencing.

Abstract: Neisseria meningitidis is a major cause of bacterial septicemia and meningitis. Sequence variation of surface-exposed proteins and cross-reactivity of the serogroup B capsular polysaccharide with human tissues have hampered efforts to develop a successful vaccine. To overcome these obstacles, the entire genome sequence of a virulent serogroup B strain (MC58) was used to identify vaccine candidates. A total of 350 candidate antigens were expressed in Escherichia coli, purified, and used to immunize mice. The sera allowed the identification of proteins that are surface exposed, that are conserved in sequence across a range of strains, and that induce a bactericidal antibody response, a property known to correlate with vaccine efficacy in humans.

Rapid Pneumococcal Evolution in Response to Clinical Interventions

Abstract: Epidemiological studies of the naturally transformable bacterial pathogen Streptococcus pneumoniae have previously been confounded by high rates of recombination. Sequencing 240 isolates of the PMEN1 (Spain23F-1) multidrug-resistant lineage enabled base substitutions to be distinguished from polymorphisms arising through horizontal sequence transfer. More than 700 recombinations were detected, with genes encoding major antigens frequently affected. Among these were 10 capsule-switching events, one of which accompanied a population shift as vaccine-escape serotype 19A isolates emerged in the USA after the introduction of the conjugate polysaccharide vaccine. The evolution of resistance to fluoroquinolones, rifampicin, and macrolides was observed to occur on multiple occasions. This study details how genomic plasticity within lineages of recombinogenic bacteria can permit adaptation to clinical interventions over remarkably short time scales.

Molecular Evolution of the Human Enteroviruses: Correlation of Serotype with VP1 Sequence and Application to Picornavirus Classification

Abstract: Sixty-six human enterovirus serotypes have been identified by serum neutralization, but the molecular determinants of the serotypes are unknown. Since the picornavirus VP1 protein contains a number of neutralization domains, we hypothesized that the VP1 sequence should correspond with neutralization (serotype) and, hence, with phylogenetic lineage. To test this hypothesis and to analyze the phylogenetic relationships among the human enteroviruses, we determined the complete VP1 sequences of the prototype strains of 47 human enterovirus serotypes and 10 antigenic variants. Our sequences, together with those available from GenBank, comprise a database of complete VP1 sequences for all 66 human enterovirus serotypes plus additional strains of seven serotypes. Phylogenetic trees constructed from complete VP1 sequences produced the same four major clusters as published trees based on partial VP2 sequences; in contrast to the VP2 trees, however, in the VP1 trees strains of the same serotype were always monophyletic. In pairwise comparisons of complete VP1 sequences, enteroviruses of the same serotype were clearly distinguished from those of heterologous serotypes, and the limits of intraserotypic divergence appeared to be about 25% nucleotide sequence difference or 12% amino acid sequence difference. Pairwise comparisons suggested that coxsackie A11 and A15 viruses should be classified as strains of the same serotype, as should coxsackie A13 and A18 viruses. Pairwise identity scores also distinguished between enteroviruses of different clusters and enteroviruses from picornaviruses of different genera. The data suggest that VP1 sequence comparisons may be valuable in enterovirus typing and in picornavirus taxonomy by assisting in the genus assignment of unclassified picornaviruses.