Serodiagnosis of recent hepatitis B infection by IgM class anti-HBc.

The time sequence, relative reactivity, and persistence of anti-HBc IgM were assessed in patients with HBsAg-positive viral hepatitis. A solid-phase immunoassay was developed using the IgM capture procedure with anti-mu-coated polystyrene beads. HBcAg was purified from serum Dane particles and used as a probe with 125I-labeled anti-HBc IgG.

Nature of human serum blood group T antibodies.

Antibodies against blood group substance T in normal human sera consist of two types, depending upon whether or not the molecules remain immunochemically active at 37 degrees C. The two agglutinins were isolated by means of T antigen-coupled Sepharose 48 affinity chromatography. Temperature-sensitive agglutinin was eluted from the affinity column at 37 degrees C, while temperature-independent agglutinin remained bound to the antigen.

Biologic properties of nontoxic derivatives of a lipopolysaccharide from Escherichia coli K235.

Lipopolysaccharide (LPS)2 from Escherichia coli K235 was treated with o-phthalic anhydride to obtain a high degree of esterification of available hydroxyl groups, leaving a free carboxyl for each hydroxyl esterified (SPLPS). Although there was no demonstrable loss of fatty acids, this conversion of LPS to a polyanionic molecule altered dramatically the spectrum of biologic properties, most of which are normally attributed to the lipid A (LA) moiety. Mitogenicity for mouse B cells was decreased several hundred-fold; reaction with antibodies to LPS was abolished; pyrogenicity and toxicity were decreased by factors of 10(5) and 10(4); the ability to induce the Shwartzman reaction in rabbits was decreased 500-fold, and the ability to stimulate production of interferon in mice was decreased by more than 2 x 10(3).

Passive hemagglutination procedure for group A streptococcal polysaccharide.

A passive hemagglutination procedure for detection of antibody to group A beta-hemolytic streptococcus polysaccharide is described. The polysaccharide was conjugated to human gamma globulin and the complex adsorbed onto stabilized human erythrocytes. Antigen coated cells were used to measure antibody levels in normal human sera and in rabbit antisera.