A hybrid toxin composed of ricin A chain and a monoclonal antibody directed against the rat nerve growth factor (NGF) receptor (192-IgG) was prepared using the heterobifunctional cross-linking agent N-succinimidyl-3-(2-pyridyldithio)-propionate and purified by affinity chromatography. Characterization studies showed that the hybrid, 192-s-s-A, displaced bound 125I-labeled 192-IgG from rat super...

A selective system was developed that permits the isolation of heterokaryons and cell hybrids between any cell types without the use of selectable genetic markers. Antibodies were introduced into two populations of non-transformed normal diploid human fibroblasts by the osmotic lysis of pinosomes containing hypertonic antibody solutions. Heterokaryons formed by fusing antiricin-injected cells t...

Intranasal (i.n.) vaccination with two suboptimal doses of 8 microg of deglycosylated chain A ricin (DGCA) stimulated low anti-ricin ELISA IgG and neutralizing antibody responses and the vaccine was only marginally protective against a lethal ricin toxin aerosol challenge. However, in the presence of 4, 2, or 1 microg of the mucosal adjuvant LTR72, a mutant of the heat-labile enterotoxin of Esc...

The oral and intraperitoneal (i.p.) toxicities to female BALB/c mice of ricin and abrin in phosphate-buffered saline (PBS), spring water, apple juice, and half-and-half (only oral) were examined after brief (2 h) and prolonged (11 to 13 days) storage. The ricin and abrin samples prepared in PBS had oral toxicities consistent with those previous studies, indicating oral and i.p. 50% lethal doses...

Ricin exhibits well characterized ribotoxic actions that lead to the inhibition of protein synthesis and the phosphorylation of stress activated protein kinases (SAPKs). Proinflammatory effects of ricin are thought to be caused by upregulation of genes encoding proinflammatory transcripts as a result of the activation of c-Jun N-terminal kinase (JNK) and p38 MAPK. We reported previously that ma...

As part of their defense mechanism against herbivores or phytophagous insects, many plant tissues contain lectins. Some of these lectins are potent toxins which kill animal cells by arresting protein synthesis. An attractive strategy for developing specifically cytotoxic chemotherapeutic agents is to link cell type-specific monoclonal antibodies to potent toxins. The plant protein ricin has eme...

This study describes the direct detection of the biological toxin (Ricin) in acidic environment without pH adjustment by hydrophobically modified electrochemical impedance immunosensor (EII). The nano-porous aluminum substrate for EII was hydrophobically modified via self-assembled monolayer (SAM) of APTES. Biosensor for the detection of the Ricin was fabricated by the covalent cross-linking of...

We here demonstrate that mastoparan, fluoride, forskolin, cholera toxin, and 8-bromoadenosine-3'-5'-cyclic monophosphate all selectively stimulate apical endocytosis of the protein toxin ricin without increasing the uptake at the basolateral side of polarized Madin-Darby canine kidney cells. Activation of adenylyl cyclase and an increased level of cAMP seem to increase ricin endocytosis by a cl...