Homologous and heterologous protection of mice with group A streptococcal M protein vaccines.

Purified streptococcal M proteins precipitated with alum (APM) were used to immunize mice. A trivalent vaccine of serotypes 1, 3, and 12 protected mice against challenges by homologous live streptococci and also conferred protection against serotypes 6 and 14 but not against a strain of group B streptococci. Monovalent APM vaccines afforded homologous protection and restricted heterologous protection.

Culture characteristics of cells derived from type II pneumocyte enriched fractions from rabbit and rat.

Type II cell enriched fractions were isolated from rabbit and rat lungs using density gradient centrifugation. Cultures established from these fractions contained predominantly cells similar in most morphological respects to type II pneumocytes. These were in continuous replicating culture for 1 year and still exhibited contact inhibition.

Antigenicity of the M proteins of group A hemolytic streptococci: further evidence for shared determinants among serotypes.

Shared antigenic determinants between M proteins of group A streptococci appear to be widespread among serotypes. This is demonstrated by the ability of purified M proteins to absorb opsonic antibody from a variety of heterologous antisera prepared against whole cells or purified M proteins. This absorption procedure has the capacity to separate passive mouse protecting and passive hemagglutinating antibodies from opsonic antibodies measured in vitro.

Protective studies with a group A streptococcal M protein vaccine. II. Challange of volenteers after local immunization in the upper respiratory tract.

Twenty-one adult volunteers were immunized at monthly intervals with three doses of purified type 1 M protein of group A Streptococcus. The soluble vaccine in buffer was administered by aerosol spray into the nares and oropharynx; 23 control subjects received a buffer placebo in the same manner. Antibody responses were observed in sera and nasal washings of some but not all vaccines.

Studies of in vitro infection by Trypanosoma cruzi. I. Ultrastructural studies on the invasion of macrophages and L-cells.

The interactions of Trypanosoma cruzi with L-cells, and with normal and activated macrophages in vitro were studied by ultrastructural techniques. T. cruzi actively invades cultured L-cells and uniformly destroys them.

Protective study with a group A streptococcal M protein vaccine. Infectivity challenge of human volunteers.

Healthy adult male volunteers were immunized with purified M protein from Group A streptococci. Type 1. The vaccine was administered subcutaneously as an aluminum hydroxide-precipitated antigen in three montly doses.

Micro complement fixation assay for type-specific group A streptococcal antibody.

A micro complement fixation assay was devised to measure the type-specificity of anti-M antibody. Unabsorbed sera were from rabbits hyperimmunized with heat-killed streptococci and from humans with naturally occurring antibody or immunized with purified M protein vaccines. These sera fixed complement only in the presence of homologous M proteins (serotypes 1, 3, 6, 12, and 14).

Sites of cytoplasmic ribonucleoprotein-filament assembly in relation to helical body formation in axenic trophozoites of Entamoeba histolytica.

Axenic trophozoites of Entamoeba histolytica showed increased logarithmic growth but absence of "chromatoid" material (stacked helical arrays of ribonucleoprotein [RNP]) when grown in an all-liquid monophasic culture. Organisms grown in a liquid overlay on a semisolid slant (biphasic medium) showed slow logarithmic growth and the presence of chromatoid material. Chromatoid material accumulated in the rapidly growing trophozoites from monophasic culture during treatment with the Vinca alkaloid, vinblastine.

Ultrastructure of bacterized and axenic trophozoites of Entamoeba histolytica with particular reference to helical bodies.

Electron microscopy of bacterized and axenic trophozoites of Entamoeba histolytica showed only slight differences in ultrastructure between the two. As with other species of Entamoeba so far studied, this species lacks typical mitochondrial structures and formed endoplasmic reticulum. Dense clusters of glycogen particles are especially characteristic in axenic amebas.