Epitope specificity of anti-HA2 antibodies induced in humans during influenza infection.

Background: The conserved, fusion-active HA2 glycopolypeptide (HA2) subunit of influenza A hemagglutinin comprises four distinct antigenic sites. Monoclonal antibodies (MAbs) recognizing three of these sites are broadly cross-reactive and protective.

Objectives: This study aimed to establish whether antibodies specific to these three antigenic sites were elicited during a natural influenza infection or by vaccination of humans.

Evaluation of clinical specimens for Rickettsia, Bartonella, Borrelia, Coxiella, Anaplasma, Franciscella and Diplorickettsia positivity using serological and molecular biology methods.

We monitored clinical samples from patients of different age groups from selected regions in Slovakia. Overall seroprevalence evaluated by immunofluorescence (IFA) using nine Bartonella, two Borrelia, six rickettsial (spotted fever and typhus group), two Coxiella, and one human granulocytic ehrlichiosis Anaplasma, Franciscella tularensis and Diplorickettsia massiliensis antigens, in rural and city populations of Slovak Republic, was found to be 32% positive for spotted fever group rickettsiae. Only five (10%) of the rickettsia-positive cases evaluated by IFA were confirmed by polymerase chain reaction.

Antibodies to PB1-F2 protein are induced in response to influenza A virus infection.

PB1-F2 is a small influenza A virus (IAV) protein encoded by an alternative (+1) reading frame of the PB1 gene. While dispensable for IAV replication in cultured cells, PB1-F2 has been implicated in IAV pathogenicity. To better understand PB1-F2 expression in vivo and its immunogenicity, we analyzed anti-PB1-F2 antibodies (Abs) in sera of mice infected intranasally (i.

Polymerase chain reaction (PCR)--an efficient tool for diagnosis of influenza and acute respiratory illnesses during influenza season.

Many severe diseases of the respiratory tract lead to hospitalisation. These diseases are often caused by viral infections and may cause increased mortality. The most common viral pathogens involved in these cases, which are also associated with significant morbidity and mortality during the influenza seasons are influenza viruses.