Fanny Lacour

Examen au microscope electronique du RNA du virus de la myeloblastose aviaire

Single-stranded RNA, with a molecular weight of 107, has been obtained by phenol extraction of avian myeloblastosis virus treated with pronase. The RNA was prepared for electron microscopy according to Kleinschmidt. The usual tangling of single-stranded RNA was avoided by diluting the purified RNA in 8 M -urea before spreading. Very long molecules, with a modal length of 8·7 μ and a mean length of 8·3 μ can be seen. Shorter pieces of variable lengths, which may be broken molecules, are also present. From the base composition, the molecular weight and the length of the intact molecules, it can be calculated that two successive bases are separated by 2·96 A

Adjuvant treatment with polyadenylic-polyuridylic acid in operable breast cancer: updated results of a randomised trial.

The results of a randomised trial of polyadenylic-polyuridylic acid given as adjuvant treatment for operable breast cancer were reviewed after a mean follow up period of 87 months. Of the 300 patients included in the original trial, 145 had been allocated to conventional treatment alone and served as controls. At the time of review the overall survival of the group given polyadenylic-polyuridylic acid was significantly improved (p less than 0.05) as compared with that of the controls given conventional treatment alone. Significant benefit (p less than 0.02) was also observed among patients with evidence of disease in lymph nodes, the best results occurring in those with up to three invaded nodes, who showed a significant increase in both overall and relapse free survival. No evidence of toxicity was recorded. These findings confirm the value of polyadenylic-polyuridylic acid as adjuvant treatment for operable breast cancer. Results in an experimental model and in patients receiving the adjuvant suggested a possible role of interferon and natural killer (NK) cells in the mechanism of action.

Enhancement of natural killer cell activity and 2‐5A synthetase in operable breast cancer patients treated with polyadenylic; polyuridylic acid

Treatment of operable breast cancer patients with a single injection of 60 mg poly(A); poly(U) (polyadenylic, polyuridylic acid) resulted in an enhancement of natural killer (NK) cell cytotoxicity against human myeloid K562 target cells. Furthermore, the level of 2–5A synthetase in peripheral blood lymphocytes of such patients was increased after the treatment. Both of these effects, measured 24 and 48 hours after the injection of poly(A); poly(U), were statistically significant compared to their respective levels before the treatment. These events, therefore, may be used as markers to monitor the immediate response of patients toward treatment with this synthetic double‐stranded RNA.

FRACTIONS WITH DIFFERING BASE COMPOSITION IN RNA FROM MALIGNANT CELLS OF MOUSE.

RNA labeled with 32 P was extracted from mouse ascites tumor cells, and centri-fuged in a linear sucrose gradient. After a pulse of 30 minutes most of the label was in a “heavy” (>30 s) and a “light” (4 to 10 s) fractions. The base composition of the fractions differed depending on whether or not sodium dodecyl-sulfate was included in the phenol extraction procedure. Without sodium dodecylsulfate the radioactivity of the “light” fraction predominated. This fraction contained a high proportion of cytosine which disappeared after treatment with phosphodiesterase. After the enzymic treatment, the base-ratios resembled those of transfer RNA. The “heavy” fraction differed from ribosomal RNA by a low proportion of adenine and a high proportion of uracil. More radioactivity was recovered after a short pulse when sodium dodecylsulfate and phenol were used. The “heavy” fraction differed from ribosomal RNA (28 8) only by slightly higher adenine and uracil contents. A DNA-like RNA was separated from transfer RNA contained in the light fraction (4 to 10 s). DNA-like RNA was also directly separated from DNA fibers. After labeling for 4·5 to 7 hr RNA was uniformly labeled, but there were still differences in the base ratios of the fractions. Ribosomal 26 to 28 s RNA had lower adenine and uracil contents than ribosomal 16 to 18 s RNA.

Antigénicité des complexes de polynucléotides

Abstract Antigenicity of polynucleotide complexes 1. Immunization of rabbits with the double-stranded helical complexes poly (A) · poly (U) and poly (I) · poly (C) adsorbed to methylated bovine serum albumin produced antibodies capable of reacting with the homologous antigens and with at least one of the constituent homopolymers. Anti-poly (A) and anti-poly (I) sera, on the other hand, do not precipitate the complexes poly (A) · poly (U) or poly (I) · poly C. 2. Cross reactions with heterologous complexes were obtained: anti-poly (A) · poly (U) sera precipitate poly (I) · poly (C), whereas they do not react (with one exception out of ten) with poly (I) or with poly (C). Anti-poly (I) · poly (C) antibodies, likewise, do not precipitate poly (A) or poly (U) but are nevertheless able to react with the double-stranded complex poly (A) · poly (U). Both groups of sera (anti-poly (A) · poly (U) and anti-poly(I) · poly (C)) cross-reacted with the triple-stranded complex poly (A) · 2 poly (U), but none reacted with the double- or triple-stranded complexes poly (G) · poly (C) or 2 poly (G) · poly (C). 3. RNA reacts with both anti-poly (A) · poly (U) and anti-poly (I) · poly (C) sera. 4. Only the anti-poly (A) · poly (U) group of sera precipitates DNA. If the deoxyribonucleic acid secondary structure is preserved, some antisera react with DNA from Micrococcus lysodeikticus and phage 2C, and also with crab poly d(A-T); but none react with DNA from Clostridium perfringens or calf thymus. However, after thermal denaturation, these DNAs are able to react.

Immunochemical study of anti poly I·poly C antibodies and of their reaction with RNA

Abstract The reaction of anti poly rI·poly rC sera with polynucleotides, polynucleotide complexes and RNA was studied by quantitative precipitin analysis. Differences in the reactivity of two polyribonucleotide complexes poly rA·poly rU and poly rG·poly rC on the one hand, and on the other hand between two complexes containing the same bases, poly rG·poly rC and poly dG·poly dC, were observed. The fact that poly dG·poly dC reacts better with anti poly rI·poly rC antibodies than does poly rG·poly rC is evidence in favor of the hypothesis that the specificity of the antibodies depends especially on the conformation of the double helix, rather that on the presence of a given base or of the nature of the sugar. The specificity of the antibodies for double stranded structures is further emphasized by the low reactivity of polynucleotides not involved in complementary hydrogen bonds. However, preliminary inhibition studies with oligoinosinicacids have given results in accord with the hypothesis of a minor population of antibodies with a different specificity. Anti poly I·poly C antibodies cross-react with RNA and particularly with reovirus RNA. They also react, although to a different extent, with ribosomal and transfer RNA. from mammalian cells. Absorption studies with polynucleotides, polynucleotide complexes and reovirus RNA have given results allowing the conclusion that it is above all the regions of associated base pairs which are recognized by the anti poly I·poly C antibodies in the RNA.

Specific Antibodies to Polynucleotide Complexes and their Reaction with Nucleic Acids: Importance of the Secondary Structure of the Antigen

It has been shown by various authors that immunization with purines, pyrimidines, nucleosides, mono-, di-, and oligo-nucleotides, or single-stranded polynucleotides (conjugated or complexed to proteins or polypeptides) gives antibodies which are specific for the bases (Butler et al., 1962; Tanenbaum and Beiser, 1963; Karol and Tanenbaum, 1967; Erlanger and Beiser, 1964; Sela et al., 1964; Plescia et al., 1964; Lacour and Harel, 1965; Halloran and Parker, 1966; Seaman et al., 1965). These antibodies react principally with denatured DNA, but not with native DNA, an indication that the immune reaction involves nucleotides that are freely accessible and not involved in a hydrogen-bonded helical secondary structure. Some of these antibodies could also react with RNA.

Polyadenylic · Polyuridylic Acid in the Cotreatment of Cancer

Abstract The biological properties of polyadenylic · polyuridylic acid (Poly(A) · Poly(U)) are discussed and the application to the treatment of cancer in various animal models is described. Pharmacokinetic properties are presented and the results of clinical application to humans with specific reference to adjuvant treatment of breast cancer are examined in some detail. Given these results and the total lack of toxicity or of secondary effects of Poly(A) · Poly(U) it appears that further development and application of this polynucleotide complex are certainly justified in terms of clinical use in cancer and perhaps in viral pathologies.

Poly(A). poly(U) as adjuvant in cancer treatment distribution and pharmacokinetics in rabbits

Abstract Rabbits were injected with poly(A) . poly(U) and the metabolic fate and stability studied using scintigraphic techniques, radioactive counting, and subcellular fractionation. The complex has a very long lifetime (measured in days) in both liver and spleen, the major locations of concentration in the animal, with about nine times more per gram of tissue in the spleen compared with the liver. In spleen cells the material is about equally divided between nuclei and cytoplasm. The polymer is slowly degraded to shorter molecules in these cells but, even 1 week after injection, significant amounts of apparently intact polynucleotide complex can be detected in both cellular fractions.

A monoclonal antibody to the double-stranded polyribonucleotide complex poly(A) · poly(U)

A monoclonal antibody to the double-stranded polyribonucleotide complex poly(A) . poly(U) was derived from the fusion of spleen cells from immunized DBA/2 mice and the P3 X X63-Ag8 plasma cytoma. Specificity studies using radioimmunoassays showed that the anti-poly(A) . poly(U) does not cross-react with single-stranded polyribonucleotides. RNA X DNA hybrids or DNAs. In addition to RNA duplexes associating adenine and uracil, it recognizes synthetic poly(I) . poly(C) and naturally occurring reovirus RNA. It is thus directed against a conformational epitope with an absolute requirement for two polyribose phosphate chains. However, the antibody does not cross-react with poly(G) . poly(C) and is therefore able to distinguish between RNA double helices.