Elimination of Is Dependent on Intraerythrocytic Killing and CD4 T Cells.

Babesiosis is a tick-borne zoonosis caused by protozoans of the genus , apicomplexan parasites that replicate within erythrocytes. However, unlike related species, the pathogenesis of infection remains poorly understood. The primary etiological agent of babesiosis in the United States is In healthy individuals, tick-transmitted infection with causes no specific clinical manifestations, with many having no symptoms at all.

Differences in SpeB protease activity among group A streptococci associated with superficial, invasive, and autoimmune disease.

The secreted cysteine proteinase SpeB is an important virulence factor of group A streptococci (GAS), whereby SpeB activity varies widely among strains. To establish the degree to which SpeB activity correlates with disease, GAS organisms were recovered from patients with pharyngitis, impetigo, invasive disease or acute rheumatic fever (ARF), and selected for analysis using rigorous sampling criteria; >300 GAS isolates were tested for SpeB activity by casein digestion assays, and each GAS isolate was scored as a SpeB-producer or non-producer. Highly significant statistical differences (p < 0.

Forward genetics screens using macrophages to identify Toxoplasma gondii genes important for resistance to IFN-γ-dependent cell autonomous immunity.

Toxoplasma gondii, the causative agent of toxoplasmosis, is an obligate intracellular protozoan pathogen. The parasite invades and replicates within virtually any warm blooded vertebrate cell type. During parasite invasion of a host cell, the parasite creates a parasitophorous vacuole (PV) that originates from the host cell membrane independent of phagocytosis within which the parasite replicates.