Immunoglobulin G in human serum neutralizes chlamydial infectivity in vitro. Complement-intact, C5-depleted, and C8-depleted human serum all have significantly more neutralizing activity than serum heated to inactivate early components of complement. Cobra venom factor, an analog of human C3b, enhances neutralization of antichlamydial immunoglobulin G in the absence of early complement components.

Background and Aims: Human parvovirus B19, a member of the parvoviridae family, with single-stranded DNA is a very minute non-enveloped virus. B 19 virus is mostly transmitted via the respiratory tract but some studies have been reported which B19 virus can be transmitted through blood and/or blood products. The aim of this study was to evaluate the prevalence of B19 among blood donors in Tehra...

Opsonization with normal human serum, purified immunoglobulin G, or immunoglobulin G-deficient serum promoted phagocytosis of Listeria monocytogenes by human peritoneal macrophages. However, normal human serum was the most effective opsonin in elicting killing and chemiluminescent responses. Macrophages phagocytized and killed almost as much as polymorphonuclear leukocytes but produced consider...

Conservation of the binding site on mammalian Na+,K+-ATPase for cardiac glycosides and the importance of the Na+ pump in mammalian cellular physiology has stimulated the search for a mammalian analog of these plant compounds. One candidate, isolated from brain and blood, appears to be ouabain itself or a closely related isomer, the ouabain-like compound. Little is known about the circulating fo...

Streptococcus pneumoniae is a gram-positive bacterial pathogen that causes invasive life-threatening disease worldwide. This organism also commonly colonizes the upper respiratory epithelium in an asymptomatic fashion. To invade, this pathogen must traverse the respiratory epithelial barrier, allowing it to cause disease locally or disseminate hematogenously throughout the body. Previous work h...

Hybrid antibodies possessing one binding site for the toxic lectin ricin and a companion site directed against human immunoglobulm were constructed in vitro. This bifunctional re agent specifically attached to human lymphocyte surface immunoglobulin determinants and, thus situated, could simulta neously capture ricin molecules or its toxic A chain. Attachment of these components to the cell was...