Fraction-I (F-I) protein, the specific antigen of Pasteurella pestis, appears to be a series of molecular aggregates of identical subunits, all of which have serological reactivity with specific F-I antiserum.

The gliding movements of Mycoplasma sp. nov. strain 163K cells were characterized by photomicrographic and microcinematographic studies. The capability of gliding proved to be a very stable property of strain 163K. Cells were continuously moving, without interruption by resting periods, on glass as well as on plastic surfaces covered with liquid medium. Gliding cells always moved in the directi...

Seropositive cotton rats cannot be immunized by intramuscular inoculation of live respiratory syncytial virus. Passively administered antiserum was shown to effect the immunosuppression. By contrast, the presence of serum antibody did not block immunization by the intranasal route.

A convenient and reliable method for serogrouping meningococci, based on immunospecific precipitation haloes in antiserum-agar plates, is described. It gave concordant results with conventional slide-agglutination in 900 strains of groups A, B or C tested. The antiserum-agar can also be used as a primary isolation medium for detecting nasopharyngeal carriers of a certain serogroup if antibiotic...

Specific anti-(human prolactin) immunoglobulin, isolated by immunoadsorption from a resolubilized Na2SO4 precipitate of a sheep antiserum, has been fractionated into antibody populations with a 10-fold range of affinity for antigen by using a new elution procedure. The procedure utilized acetonitrile (20%, v/v) in a gradient of pH, decreasing from pH 7 to pH2. The recovered immunoglobulin (74.3...

Data are given, for seven different antisera, for the composition of the specific precipitate as a function of the relative proportions of antiserum and antigen used. In the region of antigen excess, a linear relation is found between the ratio of antibody to antigen in the precipitate and the amount of antiserum used. The significance of these results, particularly in their bearing on theories...

The host-range proteins of lambda and phi80, while differing sharply in host-receptor specificity and in sensitivity to phage-killing antiserum, can be assembled into functional phage tail structures of mixed composition.

Wild mice immunosuppressed with antithymocytic sera show a high incidence of disseminated virulent cytomegalovirus infection.

The capacity to precipitate quantitatively with homologous antiserum of native protoplasmic polysaccharide from Escherichia coli was not reduced by incubation in human plasma; it was reduced with the immunochemically related lipopolysaccharide.