IgM memory B cells induced in response to adopt a germinal centre B cell phenotype during secondary infection.

Emerging evidence started to delineate multiple layers of memory B cells, with distinct effector functions during recall responses. Whereas most studies examining long-lived memory B cell responses have focussed on the IgG+ memory B cell compartment, IgM+ memory B cells have only recently started to receive attention. It has been proposed that unlike IgG+ memory B cells, which differentiate into antibody-secreting plasma cells upon antigen re-encounter, IgM+ memory B cells might have the additional capacity to establish secondary germinal centre (GC) responses.

Transcription Factor T-bet in B Cells Modulates Germinal Center Polarization and Antibody Affinity Maturation in Response to Malaria.

Despite the key role that antibodies play in protection, the cellular processes mediating the acquisition of humoral immunity against malaria are not fully understood. Using an infection model of severe malaria, we find that germinal center (GC) B cells upregulate the transcription factor T-bet during infection. Molecular and cellular analyses reveal that T-bet in B cells is required not only for IgG switching but also favors commitment of B cells to the dark zone of the GC.

Spatial organization of protein export in malaria parasite blood stages.

Plasmodium falciparum, which causes malaria, extensively remodels its human host cells, particularly erythrocytes. Remodelling is essential for parasite survival by helping to avoid host immunity and assisting in the uptake of plasma nutrients to fuel rapid growth. Host cell renovation is carried out by hundreds of parasite effector proteins that are exported into the erythrocyte across an enveloping parasitophorous vacuole membrane (PVM).

[Toxoplasmosis in families. II. Clinical analysis].

Clinical and serological analysis was conducted on 102 families including index-cases of lymphonodular toxoplasmosis (102 patients-group A) and 286 family members (group B). The studies included a total of 388 persons (167 children and 221 adults), originating mainly from Wielkopolska region (West Poland). The lymphonodular form of toxoplasmosis represented the dominating pattern among adult cases but among children the clinical pathology pattern was variable: in 14 out of 49 children (group A) lymphadenopathy was not dominating sign and clinically signs and symptoms of central nervous system or organ of vision involvement prevailed; in 6 cases clinical pattern pointed to congenital toxoplasmosis and in 8 cases it indicated sequele of acquired toxoplasmosis.

[Toxoplasmosis in families. I. Detection of T. gondii invasion and serological appraisal].

Toxoplasmosis was studied in 102 families, in which index-cases manifested the fully symptomatic course of the acquired lymphnodular toxoplasmosis, confirmed by presence of IgM and IgG class antibodies (ELISA, Vidas, BioMerieux). The index-cases (group A) provided a rational index of the acquired invasion or its late sequele in other families members. The studies were performed in 388 persons, originating from Wielkopolska region, including 102 patients of a group A and 286 of families members of group B (167 children and 221 adults).

Detection of Trichinella SP. invasion and clinical appraisal of patients in the late stage of trichinellosis in a new epidemic focus in Wielkopolska.

A clinical and an epidemiological analysis was presented of a trichinellosis focus from Wielkopolska region. The studies included 20 persons and trichinellosis was diagnosed in 15 cases. The focus was characterized by asynchronous invasion with Trichinella sp.