E De Maeyer

Delayed-type hypersensitivity to sheep red blood cells: inhibition of sensitization by interferon

Interferon, when given or induced 24 hours before contact of mice with sheep red blood cells, prevented sensitization, and no delayed-type hypersensitivity reaction could be elicited 4 days later, after challenge with the antigen, as shown by the absence of footpad swelling in treated animals.

Two-sided Effect of Steroids on Interferon in Tissue Culture

IN the course of an investigation of interferon production in a line of rat tumour cells (DE7R cells), infected with Sindbis virus Δ′,17α-methyltestosterone (‘Dianabol’, Ciba), an androgenic steroid known to increase protein synthesis in rats1 was added to the virus-cell system, in the hope of obtaining higher interferon yields. The effect of ‘Cortisol’ was evaluated at the same time in order to compare the action of a glucocorticoid known to decrease protein anabolism in vivo2 with that of an androgen. The methods used for preparing the interferon and to test for its activity have been previously described in detail3.

Interferon Synthesis in X-irradiated Animals: II. Restoration by Bone-marrow Transplantation of Circulating-interferon Production in Lethally-irradiated Mice

SummaryC3H/He mice were exposed to 1000 R whole-body x-irradiation. Circulating-interferon levels induced in these animals after intravenous injection of Sindbis or Newcastle disease virus were reduced to less than 10 per cent of their normal values. The circulating-interferon-producing capacity could be restored by treatment with isologous bone-marrow cells, immediately after irradiation. The degree of restoration of interferon formation was closely related to the degree of restoration of haemopoietic function, as indicated by experiments where irradiated animals were treated with either a minimal (2 × 105) or an optimal (107) number of isologous marrow cells. This suggested a direct relationship between bone-marrow function and the circulating-interferon-producing system. Evidence that circulating-interferon-producing cells are largely derived from bone-marrow was obtained by restoring irradiated C3H/He mice with Wistar rat marrow. In these rat to mouse chimaeras, circulating interferon, induced by eith...

INTERFERON SYNTHESIS IN X-IRRADIATED ANIMALS. III. THE HIGH RADIOSENSITIVITY OF MYXOVIRUS-INDUCED CIRCULATING INTERFERON PRODUCTION.

Summary The effect of X-irradiation on circulating interferon induction was examined in C3H/He mice, 4 days after total-body exposure to 125, 250, 500, or 1000 R. Nine viruses were tested as inducer: Newcastle disease, influenza A, Sendai, mumps, Sindbis, Semliki Forest, vesicular stomatitis, encephalomyocarditis, and vaccinia. Interferon induction by the four myxoviruses was very radiosensitive, exposure to 125 R being sufficient to reduce serum interferon levels to values ranging between 4 and 28% of levels in control animals. In contrast, interferon induction by either encephalomyocarditis or vaccinia viruses was very radioresistant, and even after 1000 R significant amounts of circulating interferon were produced. Circulating interferon induction by vesicular stomatitis, Sindbis and Semliki Forest was of intermediate radiosensitivity. The high radiosensitivty of myxovirus-induced circulating interferon production suggests an involvement of lymphocytes in circulating interferon induction by these viruses.

Inhibition of interferon synthesis by triethylenemelamine and 4-nitroquinoline-N-Oxide

Two carcinogenic compounds of different chemical structure have been studied for their effect on interferon synthesis. The first compound examined was the weakly carcinogenic alkylating agent triethylenemelamine (TEM). The second compound examined was the highly carcinogenic bicyclic compound 4-Nitroquinoline-N-Oxide (4-NQO). Pretreatment of rat embryo cell cultures with either TEM or 4-NQO, at doses of 1 to 0.01 μg/ml, and 0.1 to 0.01 μg/ml respectively, inhibited the synthesis of interferon upon subsequent infection of these cultures with Semliki Forest virus. In view of the previously reported inhibition of interferon synthesis by polycyclic aromatic carcinogens and by ultraviolet light, it becomes evident that carcinogenic agents of a widely different nature are capable of inhibiting the synthesis of interferon.

A Four Point Assay for testing Poliovaccine.

Although poliovaccination is now in its 4th year, no test exists which can accurately determine the potency of a vaccine. A four point assay is proposed with a standard deviation of 0.1 to 0.15 log10 units. It is based on a linear relation between log dose and log geometric mean titer. However, in order to compare several vaccines, more research is needed on a reference antigen.

Nos Experiences Avec La Souche Far-East

SummaryAt regular intervals, new strains of type A influenza virus, immunologically distinct from the previous ones, strike unprotected population.This year, a new strain appeared, the Far-East strain, which rapidly invaded the whole world.After a general survey of influenza, we are presenting our experience with the type A/Singapour/1/57 virus.1. The inoculation of material obtained at the beginning of the disease permitted the isolation of the virus in 12 cases out of 14. Between the 5th and 10th days of illness, the isolation was successful in only 1 case out of 4.Several successive fatal cases were observed. In a case of influenzal encephalitis the virus was isolated from autopsy material. This could indicate the acquisition of neurotropic properties by the influenza virus.2. The evolution of the antibody titers was followed by the complement-fixation and hemagglutination inhibition tests. A significant rise in the antibody levels was generally noted in convalescent individuals. I.H. antibodies attain...