Protection from Streptococcus pneumoniae keratitis by passive immunization with pneumolysin antiserum.

PURPOSE: To determine whether passive immunization with pneumolysin antiserum can reduce corneal damage associated with pneumococcal keratitis. METHODS: New Zealand White rabbits were intrastromally injected with Streptococcus pneumoniae and then passively immunized with control serum, antiserum against heat-inactivated pneumolysin (HI-PLY), or antiserum against cytotoxin-negative pneumolysin (psiPLY). Slit lamp examinations (SLEs) were performed at 24, 36, and 48 hours after infection. An additional four corneas from rabbits passively immunized with antiserum against psiPLY were examined up to 14 days after infection. Colony forming units (CFUs) were quantitated from corneas extracted at 20 and 48 hours after infection. Histopathology of rabbit eyes was performed at 48 hours after infection. RESULTS: SLE scores at 36 and 48 hours after infection were significantly lower in rabbits passively immunized with HI-PLY antiserum than in control rabbits (P < or = 0.043). SLE scores at 24, 36, and 48 hours after infection were significantly lower in rabbits passively immunized with psiPLY antiserum than in control rabbits (P < or = 0.010). The corneas of passively immunized rabbits that were examined up to 14 days after infection exhibited a sequential decrease in keratitis, with an SLE score average of 2.000 +/- 1.586 at 14 days. CFUs recovered from infected corneas were not significantly different between each experimental group and the respective control group at 20 or 48 hours after infection (P > or = 0.335). Histologic sections showed more corneal edema and polymorphonuclear leukocyte (PMN) infiltration in control rabbits compared with passively immunized rabbits. CONCLUSIONS: HI-PLY and psiPLY both elicit antibodies that provide passive protection against S. pneumoniae keratitis.

Isolation and characterization of human nuclear and cytosolic multisynthetase complexes and the intracellular distribution of p43/EMAPII.

In this study, the human multienzyme aminoacyl-tRNA synthetase "core" complex has been isolated from the nuclear and cytosolic compartments of human cells and purified to near homogeneity. It is clear from the polypeptide compositions, stoichiometries, and three-dimensional structures that the cytosolic and nuclear particles are very similar to each other and to the particle obtained from rabbit reticulocytes. The most significant difference observed via aminoacylation activity assays and densitometric analysis of electrophoretic band patterns is a lower amount of glutaminyl-tRNA synthetase in the human particles. However, this is not enough to cause major changes in the three-dimensional structures calculated from samples negatively stained with either uranyl acetate or methylamine vanadate. Indeed, the latter samples produce volumes that are highly similar to an initial structure previously calculated from a frozen hydrated sample of the rabbit multisynthetase complex. New structures in this study reveal that the three major structural domains have discrete subsections. This information is an important step toward determination of specific protein interactions and arrangements within the multisynthetase core complex and understanding of the particle's cellular function(s). Finally, gel filtration and immunoblot analysis demonstrate that a major biological role for the cytokine precursor p43 is as an integral part of the multisynthetase complex.