Immunization with ribosomal preparations from Haemophilus influenzae type b elicited protective immunity in mice. Ribosomes from disrupted cells where isolated by differential centrifugation using sodium dodecyl sulfate. The washed ribosomes contained 25% protein and 75% ribonucleic acid and sedimented as a single peak on sucrose density gradient analysis with a sedimentation coefficient of 67S, using Escherichia coli ribosomes as a 70S marker. Immunodiffusion tests with antipolyribose phosphate serum showed that the ribosomes were free from capsular material. Mice immunized subcutaneously with ribosomes, with or without adjuvant, were challenged intraperitoneally with 100 to 1,000 mean lethal doses of H. influenzae type b suspended in gastric mucin. Significant protection was induced by ribosomes and was compared to that obtained after sublethal infection with live cells. The protection was greatly enhanced after incorporation of ribosomes into adjuvants. Maximum protection (90 to 95%) was observed at 1 to 2 weeks after immunization. Ribosomes from a nonencapsulated strain of H. influenzae were as immunogenic as those from the encapsulated strain, demonstrating that the capsular material is not responsible for immunogenicity of Haemophilus ribosomes.

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This investigation was designed to characterize the immunoprotective antigen of ribosomal preparations from Haemophilus influenzae. The ribosomes that elicited 80 to 90% protection contained 25% protein and 75% ribonucleic acid but did not contain any detectable hexoses. The immunodiffusion and hemagglutination inhibition tests also failed to demonstrate that the capsular material (polyribose phosphate) was in ribosomal preparations. Treatment of ribosomes with ribonuclease degraded 78% ribonucleic acid but did not affect the immunogenicity of such preparations. The proteolytic enzymes reduced the immunogenicity of ribosomes corresponding to the amount of protein degraded. The protection elicited by ribosomal protein extracted with 2-chloroethanol was comparable to that induced by intact ribosomes. In contrast, the low levels of protection observed by immunization with phenol-extracted ribonucleic acid were dependent on the amounts of contaminating protein. Finally, immunogenicity of ribosomal ribonucleic acid and protein was abrogated by treatment with proteolytic enzymes. These results clearly indicate that the protein associated with Haemophilus ribosomes is the major immunoprotective antigen.

SUMMARYThree filamentous micro-organisms are described. They are typical Actinomycetales forming branching hyphae, 1.5 p or less in diameter, which are differentiated into a substrate (primary) mycelium and an aerial (secondary) mycelium. They have an unusual mode of sporulation since they form chains of conidia both on the substrate and on the aerial mycelium. A new genus, Micropolyspora, is proposed. The type species is M . brevicatena. The new genus is part of the family Actinomycetaceae. The abolition of the family Streptomycetaceae is proposed.

The comparative efficacy of amphotericin B and amphotericin B methyl ester (AME) against experimental histoplasmosis, blastomycosis, cryptococcosis, and candidosis in mice was assessed by determining the effect of daily intraperitoneal therapy on 21-day survival and persistence of organisms in internal organs. AME, like amphotericin B, was effective against each of the experimental infections, but the efficacy was lower than the parent compound. For Histoplasma and Blastomyces infections the mean effective dose (ED50) of amphotericin B was 0.3 mg/kg, whereas the corresponding values for AME, respectively, were 2.4 and 2.8 mg/kg. For Cryptococcus infection the ED50 for amphotericin B was 0.2 mg/kg compared with 2.0 mg/kg for AME. The ED.0 of amphotericin B for Candida infection was lower than 0.05 mg/kg and the value of AME was between 0.5 to 0.05 mg/kg. The colony counts from internal organs of the surviving animals after the therapeutic regimens were compatible with the data on survival.

The in vitro antifungal activity of amphotericin B methyl ester (AME), a water-soluble derivative of amphotericin B, was compared to that of the parent compound against a variety of pathogenic and potentially pathogenic fungi. AME has a significant antifungal activity, but the activity of AME was slightly lower than that of amphotericin B. Among the yeast-like organisms, only the yeast cells of Sporothrix schenckii were more resistant than others to both antibiotics, with a minimal fungicidal concentration of 5 to 10,ug/ml. The yeast cells of other fungi were killed at concentrations of 1 yg or less of either antibiotic per ml. The filamentous forms of S. schenckii and Oidiodendron kalrai were more resistant than the filamentous forms of other dimorphic fungi to both drugs. The minimal fungicidal concentration for S. schenckii was 10 ;g/ml and for 0. kalrai, 50 ug/ml. The dermatophytes, phycomycetes, and dematacious and other potentially pathogenic fungi were inhibited fairly well by both drugs, but up to 50 ,ug/ml was required for fungicidal action. The water solubility and wide spectrum of antifungal activity of AME warrant evaluation of its chemotherapeutic activity against experimental fungal infections.

This investigation was designed to compare the role of lymphoid cells and immune serum in protective immunity induced by immunization with ribosomes or live yeast cells of Histoplasma capsulatum. Spleen cells, peritoneal cells, and serum from CH mice immunized with Histoplasma ribosomes or live cells were transferred intravenously to separate groups of syngeneic recipients. All recipients along with a set of immunized and control mice were challenged intravenously with 4 x 106 yeast cells of H. capsulatum, and protection was assessed. Immunization with ribosomes or live cells provided 90 to 100% protection. Mice receiving filtered spleen cells or peritoneal cells from donors immunized with live cells showed 90 to 100% protection; 80 to 90% protection was observed for mice receiving cells from ribosome-immunized donors. In contrast, no evidence of protection was seen in mice receiving serum from either live-cellor ribosome-immunized mice. Peritoneal cells were far more efficient than spleen cells in adoptive transfer of immunity. The adoptive immunity in recipients persisted for at least 3 weeks after transfer, the longest period tested in the present study. These results indicate that the immunity elicited by immunization with Histoplasma ribosomes or live cells is mediated by a cellular mechanism.