Inhibitory effect of sera from rheumatoid arthritis patients and enhancing effect of levamisole on total E-rosette levels of lymphoid cells from normal and RA subjects.

We determined the E-rosette levels (E-R) in rheumatoid arthritis patients (RA) and repeatedly tested a selected group with depressed E-R. We also evaluated, in vitro, the inhibitory effect of RA sera on normal E-R and the enhancing effect of levamisole (LV) on normal and RA E-R. Selection criteria and E-R protocol were those of Di Perri (1979).

The action of human and rabbit serum phospholipase A2 on Escherichia coli phospholipids.

We have compared the properties of phospholipase A (E.C. 3.

Resistance of gram-negative bacteria to purified bactericidal leukocyte proteins: relation to binding and bacterial lipopolysaccharide structure.

The sensitivity or resistance of gram-negative bacteria to antibacterial systems appears to be related to the length of the saccharide chain of the bacterial envelope lipopolysaccharides (LPS). To explore this relationship further, we made use of two bactericidal, membrane-active cationic proteins, recently purified to near homogeneity, one from human and one from rabbit polymorphonuclear leukocytes (PMN). We have studied the effects of these two closely similar proteins on strains of Salmonella typhimurium and Escherichia coli, each separate strain differing in the saccharide chain length of its outer membrane LPS.

Separation and purification of a potent bactericidal/permeability-increasing protein and a closely associated phospholipase A2 from rabbit polymorphonuclear leukocytes. Observations on their relationship.

Two antibacterial proteins from rabbit polymorphonuclear leukocytes, a potent bactericidal cationic protein that increases the envelope permeability of susceptible gram-negative bacteria and a phospholipase A2, have been purified to near homogeneity by ion exchange, gel filtration, and hydrophobic interaction chromatography. The apparently noncatalytic bactericidal/permeability-increasing protein has an approximate molecular weight of 50,000 and is isoelectric at pH 9.5 to 10.

Effects of human and rabbit serum on viability, permeability, and envelope lipids of Serratia marcescens.

The major action of serum on gram-negative organisms is thought to be on the microbial envelope. We compared the effects of normal human and rabbit serum on the envelope lipids of two strains of Serratia marcescens, one sensitive and one resistant to the bactericidal effects of serum. During killing by either serum, the sensitive strain underwent rapid permeability changes coincident with degradation of microbial phospholipids.